Simulation of Microstructured Rolling-Sliding Contacts - Weschta, Martin; Tremmel, Stephan; Wartzack, Sandro (Proceedings of the 2014 COMSOL Conference in Boston, 2014)
To reduce friction in lubricated tribological contacts, the surfaces of the contacting bodies can be microstructured to improve lubricating conditions. For lower loaded contacts this approach has already reached industrial applications, e.g. the piston-liner contact. For higher loaded contacts the effects are currently in basic research. Elastic deformation in the contact area plays an important role in those cases. This paper presents an approach to compute microstructured elastohydrodynamic contacts using COMSOL Multiphysics® software and compares results with those attained on a test bench.
UnivIS-Import:2015-10-26:Pub.2014.tech.FT.FT-KLMEFK.simula

Simulation of Microtextured Surfaces in Starved EHL Contacts Using Commercial FE Software - Marian, Max; Weschta, Martin; Tremmel, Stephan; Wartzack, Sandro (Materials Performance and Characterization, 2017)
In order to improve the lubricating conditions and thus realize a reduction of friction and wear, the surfaces of contacting bodies in lubricated tribological contacts can be microtextured. Although this approach has already reached industrial applications for lower loaded contacts, it is still in basic research for higher loaded contacts, where elastic deformation plays a significant role. In the past, it was common in theoretical studies to assume a fully flooded condition for the inlet to the contact. However, in reality a lubricant contact may suffer from starvation due to high speeds, highly viscous lubricants, or limited lubricant supply. This article presents an efficient straightforward approach to compute starved microtextured elastohydrodynamic contacts based on a full-system approach and using commercial FE software. The numerical study on starvation is realized by shifting the position of the inlet meniscus toward the contact zone combined with the use of an appropriate cavitation model. Therefore, negative pressures are penalized by reducing the lubricant’s density, respectively its volume or mass fraction, with a penalty term. First, the implementation for the steady-state smooth-surface problem as well as the impact of decreasing lubricant supply on the film thickness are discussed as a reference case. Special is paid to proving suitability and validity of the used cavitation model for starvation problems. Subsequently, the influence of different degrees of starvation on film thickness and pressure distribution for a microtextured time-dependent demonstrator case is illustrate
Keywords: tribology; lubrication; microtextured surfaces; elastohydrodynamics; finite-element-method; penalty-variable-density; cavitation model; mass conservation; starvation

Simulationsbasierte Generierung von Präparationsrichtlinien für Zahn-Inlays im kaubelasteten Seitenzahnbereich - Klein, Daniel; Grimme, Tobias; Tremmel, Stephan; Petschelt, Anselm; Lohbauer, Ulrich; Wartzack, Sandro (ANSYS Conference & CADFEM User's Meeting 2012, 2012)
Caries is the major dental disease and the main reason for tooth extractions as clinical investigations show. Fortunately in many cases the carious lesion can be removed without extracting the whole tooth and replaced by a restoration, e.g. inlays. However, the lifetime of inlays is limited. Besides the inlay material the geomtery of the inlay can have a significant impact on the durability of an inlay. The aim of this paper is to show how the impact of the inlay geometry on the durability can be observed with the help of simulation and some common guidelines for dental restaurations are monitored.
Keywords: Simulation; Medizintechnik

Simulations-DNA: Datengetriebener Ansatz zur automatischen Plausibilitätsprüfung strukturmechanischer FE-Simulationen mittels Deep Learning - Sprügel, Tobias; Schleich, Benjamin; Wartzack, Sandro (VDI Bereichte 2333: SIMVEC - Simulation und Erprobung in der Fahrzeugentwicklung 2018, 2018)
In der modernen virtuellen Produktentwicklung ist der Einsatz von Simulationswerkzeuge zur Beurteilung der Auswirkungen von Konstruktionsänderungen auf das beabsichtigte Produktverhalten unerlässlich. Die Erstellung valider Simulationen erfordert jedoch Expertenwissen. Konstrukteure, die selten Finite-Elemente-Analysen (FEA) durchführen, müssen unterstützt und ihre FEA-Ergebnisse auf Plausibilität überprüft werden. Eine automatische Plausibilitätsprüfung für Finite Elemente (FE) Simulationen in der linearen Strukturmechanik kann nicht plausible Simulationen identifizieren und den Anwender warnen, die Ergebnisse vorsichtig zu interpretieren oder Rücksprache mit Simulationsexperten zu halten. Eine nicht plausible Simulation enthält Fehler, die von einem erfahrenen Simulationsingenieur schnell erkannt werden, während eine plausible Simulation solche Fehler nicht enthält. Die Menge der verfügbaren Simulationsdaten in der Industrie nimmt zu, daher ist eine datengetriebene Simulationsprüfung ein naheliegender nächster Schritt. Dennoch stellt sich die Frage, wie Simulationsdaten sehr unterschiedlicher Bauteile und Simulationen in ein einziges Softwaretool übertragen werden können, wie dieses Tool die relevanten Regeln hinter plausiblen Simulationen erlernen kann und wie es auf neue Simulationen angewendet werden kann. In diesem Beitrag wird ein Ansatz zur Umwandlung verschiedener FE-Netze, entsprechender FE-Ergebnisse und Randbedingungen in eine numerische Matrix fester Größe für sehr unterschiedliche strukturmechanische FE-Simulationen vorgestellt. Der neuartige Ansatz nutzt sphärische Detektorflächen, um dreidimensionale Informationen auf die Oberfläche zu projizieren. Es ermöglicht die Erzeugung der sogenannten Simulations-DNA; Klassifikationsalgorithmen wie z. B. Convolutional Neural Networks können diese Informationen klassifizieren. Die gesamte Methodik reduziert die Dimension einer 3D-Finite-Elemente-Simulation auf eine 2D-Matrix fixer Größe, bestehend aus numerischen Werten. Im Beitrag wird jeder einzelne Schritt der neuartigen Methodik zur Plausibilitätsprüfung von strukturmechanischen Simulationen für vereinfachte Bauteile und entsprechende Simulationen detailliert dargestellt und erläuter
Keywords: Deep Learning; Plausibilitätsprüfung; FE-Simulation; Sphärische Detektorfläche

Simulationsstrategie als Basis für Industrie 4.0 - Wartzack, Sandro (CADFEM Journal, 2015)
UnivIS-Import:2015-10-26:Pub.2015.tech.FT.FT-KLMEFK.simula

Simulationsstrategie zur Abbildung des abweichungsbehafteten Herstellungsprozesses von Faser-Kunststoff-Verbund-Baugruppen - Freitag, Stephan; Götz, Stefan; Wartzack, Sandro (Tagungsband der 5. Summer School Toleranzmanagement 2023, 2023)

Simulative Parameterstudien an Wellblech-Sandwichstrukturen - Gruber, Georg; Wartzack, Sandro (ANSYS Conference & 29th CADFEM Users' Meeting, 2011)
UnivIS-Import:2015-04-16:Pub.2011.tech.FT.FT-KLMEFK.simula_6

SIMULTANEOUS DEFINITION OF KEY CHARACTERISTICS IN ORDER TO FACILITATE ROBUST DESIGN IN EARLY PRODUCT DEVELOPMENT STAGES - Götz, Stefan; Horber, Dennis; Schleich, Benjamin; Wartzack, Sandro (Proceedings of the Design Society, 2021)
The success of complex product development projects strongly depends on the clear definition of target factors that allow a reliable statement about the fulfilment of the product requirements. In the context of tolerancing and robust design, Key Characteristics (KCs) have been established for this purpose and form the basis for all downstream activities. In order to integrate the activities related to the KC definition into product development as early as possible, the often vaguely formulated requirements must be translated into quantifiable KCs. However, this is primarily a manual process, so the results strongly depend on the experience of the design engineer. In order to overcome this problem, a novel computer-aided approach is presented, which automatically derives associated functions and KCs already during the definition of product requirements. The approach uses natural language processing and formalized design knowledge to extract and provide implicit information from the requirements. This leads to a clear definition of the requirements and KCs and thus creates a founded basis for robustness evaluation at the beginning of the concept design stage. The approach is exemplarily applied to a window lifter.
Keywords: Robust design; Conceptual design; Requirements; Early design phases

Simultaneous Development of a Self-learning Engineering Assistance System - Sauer, Christopher; Schleich, Benjamin; Wartzack, Sandro (Sheet Bulk Metal Forming. Research Results of the TCRC73, 2020)
In order to support the design of sheet-bulk metal formed parts, a self-learning engineering assistance system (SLASSY) was developed during the course of the project. SLASSY can help in product development of sheet-bulk metal forming (SBMF) mainly in two ways. On the one hand, it facilitates the knowledge transfer from manufacturing experts back to product developers and on the other hand, it enables product developers to optimize their part designs based on the metamodels created from simulation and experimental parameter studies. The key scientific findings are the generalized workflow for creating these metamodels, which allows the creation of knowledge very soon during the development of a new manufacturing technology like SBMF. Based on this, metamodels allow the automatic generation of design alternatives, which are also valuable and manufacturable. Potential applications for this self-learning engineering assistance system can be found in every manufacturing-related industry, since it enables product developers to keep up with the development of a new or newly introduced manufacturing technology in their respective field. The methods developed can be applied to all fields, where simulations and experimental studies are applied to find new knowledge in a given manufacturing domai
Keywords: data driven design; engineering workbench; machine learning

Skin Model Based Simulation of Contact and Mobility for Mechanical Assemblies - Schleich, Benjamin; Anwer, Nabil; Zhang, Wei; Mathieu, Luc; Wartzack, Sandro (Proceedings of the 13th CIRP Conference on Computer Aided Tolerancing, 2014)
UnivIS-Import:2015-04-16:Pub.2014.tech.FT.FT-KLMEFK.skinmo_8

Skin Model Shapes: A new Paradigm for the Tolerance Analysis and the Geometrical Variations Modelling in Mechanical Engineering - Schleich, Benjamin (VDI Verlag, 2017)
Die vorliegende Arbeit wendet sich an Ingenieure und Wissenschaftler aus dem Bereich der virtuellen Produktentwicklung und angrenzender Disziplinen mit Schwerpunkt auf dem Toleranzmanagement. Sie stellt ein umfassendes Rahmenwerk für die Toleranzsimulation unter Berücksichtigung von Formabweichungen in Übereinstimmung mit internationalen Normen zur Geometrischen Produktspezifikation vor. Hierzu werden Algorithmen für die Erzeugung abweichungsbehafteter Punktwolken und Oberflächennetze (Skin Model Shapes), für deren Skalierung sowie deren Montagesimulation erarbeitet. Darüber hinaus behandelt die Arbeit die Toleranzanalyse bewegter Mechanismen und stellt einen Software-Prototypen für die Toleranzsimulation mittels Oberflächennetzen vor. Auf Basis der kritischen Gegenüberstellung von Ergebnissen des erarbeiteten Verfahrens mit bestehenden Toleranzanalysemethoden für typische Problemfälle wird gezeigt, dass durch die Berücksichtigung von Formabweichungen bei der Toleranzanalyse die Einflüsse von Bauteilabweichungen auf die Funktion und Qualität mechanischer Baugruppen und bewegter Systeme deutlich realitätsnäher bestimmt und dadurch Toleranzentscheidungen optimiert werden können.
Keywords: Simulation; Toleranzanalyse; Toleranzmanagement; Produktentwicklung; Konstruktion; Robust Design; Unsicherheit; Dimensional Management; Geometrische Produktspezifikation; Skin Model Shapes

Skin Model Shapes: A new paradigm shift for geometric variations modelling in mechanical engineering - Schleich, Benjamin; Anwer, Nabil; Mathieu, Luc; Wartzack, Sandro (Computer-Aided Design, 2014)
Geometric deviations are inevitably observable on manufactured workpieces and have huge influences on the quality and function of mechanical products. Therefore, many activities in geometric variations management have to be performed to ensure the product function despite the presence of these deviations. Dimensional and Geometrical Product Specification and Verification (GPS) are standards for the description of workpieces. Their lately revision grounds on GeoSpelling, which is a univocal language for geometric product specification and verification and aims at providing a common understanding of geometric specifications in design, manufacturing, and inspection. The Skin Model concept is a basic concept within GeoSpelling and is an abstract model of the physical interface between a workpiece and its environment. In contrast to this understanding, established models for computer-aided modelling and engineering simulations make severe assumptions about the workpiece surface. Therefore, this paper deals with operationalizing the Skin Model concept in discrete geometry for the use in geometric variations management. For this purpose, Skin Model Shapes, which are particular Skin Model representatives from a simulation perspective, are generated. In this regard, a Skin Model Shape is a specific outcome of the conceptual Skin Model and comprises deviations from manufacturing and assembly. The process for generating Skin Model Shapes is split into a prediction and an observation stage with respect to the available information and knowledge about expected geometric deviations. Moreover, applications for these Skin Model Shapes in the context of mechanical engineering are given.
UnivIS-Import:2015-03-09:Pub.2014.tech.FT.FT-KLMEFK.skinmo
Keywords: Geometric variations management; Computer aided tolerancing; Geometric product specification; Skin Model; Shape modelling; Shape representation

Skin Model Shapes: ein neuer Ansatz zur Toleranzsimulation auf Basis von Punktwolken und Oberflächennetzen - Schleich, Benjamin; Wartzack, Sandro (Konstruktion, 2017)
Die Toleranzsimulation ist ein essentielles Werkzeug zur frühzeitigen Analyse der Auswirkungen von Bauteil- abweichungen auf funktions- und qualitätskritische Baugruppenmaße. Dieser Beitrag stellt einen neuen Ansatz zur Toleranzsimulation auf Basis von Punktwolken und Ober-flächennetzen unter Berücksichtigung von Formabweichungen und in Übereinstimmung mit Toleranznormen vor und erläutert das, diesem Ansatz zugrundeliegende, Konzept der Skin Model Shapes.

Skin Model Shapes: Offering New Potentials for Modelling Product Shape Variability - Schleich, Benjamin; Wartzack, Sandro; Anwer, Nabil; Mathieu, Luc (ASME 2015 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, Volume 1A: 35th Computers and Information in Engineering Conference, 2015)
The modelling of nominal product geometry by computer-aided design tools has gained immense attention in industry during the last decades and is nowadays an integral part of the virtual product development process. However, the established geometry representation schemes for CAD imply severe drawbacks regarding the modelling of geometric part deviations, which are inevitably observed on every manufactured artefact. As a response, the concept of Skin Model Shapes, which stems from international standards for geometric product specification and verification, has been developed as a novel approach for the consideration of product shape variability. It employs discrete geometry methods and computational techniques, such as point clouds, surface meshes and geometric processing, to model shape variability and to facilitate the communication of geometric product information throughout the product design, manufacturing, and inspection processes. This paper highlights the foundations of this concept, demonstrates its potentials for the representation of product geometry considering geometric variations along the product lifecycle, and illustrates main applications in the context of computer aided product and process development. In this regard, a focus is laid upon recent results and contributions, such as contact modelling, tolerance analysis, and motion tolerancing based on Skin Model Shapes. Furthermore, challenges for future research, such as the application to complex shapes and compliant parts, as well as the consideration of novel manufacturing processes, are discussed.
Keywords: Computer-Aided Tolerancing; Tolerance Modelling; Skin Model Shapes

SLASSY—An Assistance System for Performing Design for Manufacturing in Sheet-Bulk Metal Forming: Architecture and Self-Learning Aspects - Sauer, Christopher; Breitsprecher, Thilo; Küstner, Christof; Schleich, Benjamin; Wartzack, Sandro (AI, 2021)
Substantial efforts have been made to integrate manufacturing- and design-relevant knowledge into product development processes. A common approach is to provide the relevant knowledge to the design engineers using a knowledge-based system (KBS) that, in turn, becomes the engineering assistance system. Keeping the knowledge up to date is a critical issue, making knowledge acquisition a bottleneck of developing and maintaining KBS. This article presents a robust metamodel optimization and performance estimation architecture for developing and maintaining a KBS useful for design-for-manufacturing from the context of sheet-bulk metal forming. It is shown that the presented KBS or engineering assistance system helps achieve performing design-for-manufacturing, integrating both design and manufacturing knowledge. Using the presented approach helps overcome the bottleneck of knowledge acquisition and knowledge update through its self-learning component based on data mining and knowledge discovery.<br
Keywords: engineering assistance system; knowledge discovery in database; sheet-bulk metal forming

So eng wie nötig, so breit wie möglich - Wartzack, Sandro; Walter, Michael; Schleich, Benjamin (Konstruktionspraxis, 2013)
UnivIS-Import:2015-03-09:Pub.2013.tech.FT.FT-KLMEFK.soengw

Soft EHL Modeling of Total Knee Arthroplasties - Marian, Max; Rothammer, Benedict; Tremmel, Stephan (International Tribology Conference Sendai 2019, 2019)
Total knee arthroplasty (TKA) is an effective surgical treatment against gonarthrosis and rheumatoid arthritis to retrieve the function of the knee. However, wear as well as associated osteolysis and aseptic loosening are the most common reasons for premature implant failure. In general, TKA consists of a metallic femoral component rubbing against the bearing surface of the (tibial) ultrahigh molecular weight polyethylene (PE‑UHMW) inlay. Several studies aim on the reduction of polymeric wear debris and thus abrasive wear by geometrical optimization or surface modification, such as micro-texturing and applying tribological coatings. For an adequate TKA design, fundamental knowledge about present lubrication conditions and stresses is vital. Therefore, a fully coupled transient 3D model of the soft elastohydrodynamically lubricated (soft EHL) contact in total knee arthroplasties was developed. For the hydrodynamics, a modified generalized Reynolds equation was applied. Based upon the finite element method (FEM), the elastic deformation was computed for an equivalent body by applying the linear elasticity equation. Moreover, for example time-dependent squeeze effects, mixed lubrication, microhydrodynamics, mass-conserving cavitation as well as thermal and non-Newtonian effects were to be considered. Numerical modeling along with exemplary results are presented and discussed within the scope of this contribution. Special emphasis is put on rheological properties of synovia from different individuals as well as synthetic synovial testing fluid. It is shown that variations in those properties, in particular viscosity, have a decisive influence on lubrication conditions and thus also on potential wear. Based on this knowledge, patient-specific geometric optimizations or surface modifications can be designe
Keywords: Human Tribology Simulation; Total Knee Arthroplasties; Finite Element Method; Soft Elastohydrodynamic Lubrication

Sonderforschungsbereich/Transregio "Blechmassivumformung" angelaufen - Wartzack, Sandro; Hetzner, Harald; Röhner, Sebastian (Konstruktion, 2010)
UnivIS-Import:2015-03-09:Pub.2010.tech.FT.FT-KLMEFK.sonder

Spider web inspired composite structures - a new concept for load introduction in fiber-reinforced-plastics sandwich structures - Franz, Michael; Völkl, Harald; Wartzack, Sandro (DS 119: Proceedings of the 33rd Symposium Design for X (DFX2022), 2022)
Sandwich structures represent a lightweight design method which leads to very light and at the same time stiff components through the combination of stiff outer skins and light core material. A major challenge in the design of sandwich structures is load introduction. In order to realize improved load introduction in sandwich structures and to leverage further possible lightweight design potential, the following paper presents a new concept using spider web inspired structures made of fiber reinforced plastic materials. In order to investigate the potential of the spider web concept, simulative comparative studies between the spider web structures and conventional load introductions are carried out<br

Standardized Characterisation of Device Power Supplies for Automated Test Generation and Simulation - Glaser, Daniel; Müller, Andreas; Lu, Ping; Uygur, Gürkan; Helmreich, Klaus (Tagungsband, 2010)
UnivIS-Import:2015-04-16:Pub.2010.tech.IE.c3scha.standa_5

Statistical Characterization of Stress Concentrations along Butt Joint Weld Seams Using Deep Neural Networks - Braun, Moritz; Neuhäusler, Josef; Denk, Martin; Renken, Finn; Kellner, Leon; Schubnell, Jan; Jung, Matthias; Rother, Klemens; Ehlers, Sören (Applied Sciences, 2022)
In order to ensure high weld qualities and structural integrity of engineering structures, it is crucial to detect areas of high stress concentrations along weld seams. Traditional inspection methods rely on visual inspection and manual weld geometry measurements. Recent advances in the field of automated measurement techniques allow virtually unrestricted numbers of inspections by laser measurements of weld profiles; however, in order to compare weld qualities of different welding processes and manufacturers, a deeper understanding of statistical distributions of stress concentrations along weld seams is required. Hence, this study presents an approach to statistically characterize different types of butt joint weld seams. For this purpose, an artificial neural network is created from 945 finite element simulations to determine stress concentration factors at butt joints. Besides higher quality of predictions compared to empirical estimation functions, the new approach can directly be applied to all types welded structures, including arc- and laser-welded butt joints, and coupled with all types of 3D-measurement devices. Furthermore, sheet thickness ranging from 1 mm to 100 mm can be assessed.<br
Keywords: local weld toe geometry; weld classification; 3-D scans; non-destructive testing; statistical assessment; machine learning; fatigue strength; stress concentration factor; weld quality; artificial neural network

Statistical tolerance analysis—a survey on awareness, use and need in german industry - Walter, Michael S.J.; Klein, Christina; Heling, Björn; Wartzack, Sandro (Applied Sciences, 2021)
The importance of geometric deviations of components for the aesthetic and functional quality of products has been undisputed for decades. So, it is not surprising that not only have numerous researchers devoted themselves to this field, but also commercial software tools for the analysis and optimization of tolerance specifications (currently already fully integrated in 3D-CAD systems) have been available for around 30 years. However, it is even more surprising that the well-founded specification of tolerances and their analysis using a so-called statistical tolerance analysis are only established in a few companies. There is thus a contradiction between the proclaimed relevance of tolerances and their actual consideration in everyday business life. Thus, the question of the significance of geometric deviations and tolerances as well as the use of statistical tolerance analysis arises. Therefore, a survey among 102 German companies was carried out. The results are presented and discussed in this paper.
CRIS-Team Scopus Importer:2021-04-09
Keywords: GD&T; German industry; Survey; Tolerance analysis; Tolerance engineering

Statistical Tolerance Analysis of 3D-Printed Non-Assembly Mechanisms in Motion Using Empirical Predictive Models - Schächtl, Paul; Schleich, Benjamin; Wartzack, Sandro (Applied Sciences, 2021)
Fused Deposition Modelling (FDM) enables the fabrication of entire non-assembly mechanisms within a single process step, making previously required assembly steps dispensable. Besides the advantages of FDM, the manufacturing of these mechanisms implies some shortcomings such as comparatively large joint clearances and geometric deviations depending on machine-specific process parameters. The current state-of-the-art concerning statistical tolerance analysis lacks in providing suitable methods for the consideration of these shortcomings, especially for 3D-printed mechanisms. Therefore, this contribution presents a novel methodology for ensuring the functionality of fully functional non-assembly mechanisms in motion by means of a statistical tolerance analysis considering geometric deviations and joint clearance. The process parameters and hence the geometric deviations are considered in terms of empirical predictive models using machine learning (ML) algorithms, which are implemented in the tolerance analysis for an early estimation of tolerances and resulting joint clearances. Missing information concerning the motion behaviour of the clearance affected joints are derived by a multi-body-simulation (MBS). The exemplarily application of the methodology to a planar 8-bar mechanism shows its applicability and benefits. The presented methodology allows evaluation of the design and the chosen process parameters of 3D-printed non-assembly mechanisms through a process-oriented tolerance analysis to fully exploit the potential of Additive Manufacturing (AM) in this field along with its ambition: ‘Print first time right’<br
Keywords: additive manufacturing; fused deposition modelling; statistical tolerance analysis; non-assembly mechanisms; empirical predictive models; geometric deviations

Statistical Tolerance Analysis of Mechanisms with Interactions between Deviations - A Methodology with 10 easy Steps - Walter, Michael; Wartzack, Sandro (Proceedings of the 19th International Conference on Engineering Design, 2013)
The time-dependent motion behavior of a mechanism is essentially affected by different kinds of deviations. Consequently, the product developer has to analyze the mechanism and its kinematic behavior as early as possible to ensure the product's functional capabilities. However, possible interactions between the deviations and their effects on the system's motion, and thus the functionality are not considered yet. This paper presents a methodology, consisting of 10 easy steps, which enables the product developer to perform a statistical tolerance analysis of a system in motion, which underlies different kinds of deviations as well as several interactions among them. Therefore, the identification as well as the determination (statistically) of the interactions is required, which can be done using numerical simulations like multi-body-dynamics or manufacturing process simulations. An appropriate mathematical representation of the interactions is done using meta-models (like Artificial Neural Networks). These can be easily integrated into the tolerance analysis' functional relation. A case study of a non-ideal cross-arm window regulator illustrates the methodology's practical use. statistical tolerance analysis, artificial neural networks, robust design, simulation, design methods.
UnivIS-Import:2015-04-16:Pub.2013.tech.FT.FT-KLMEFK.statis_2

Statistical Tolerance-Cost-Optimization of Systems in Motion Taking into Account Different Kinds of Deviations - Walter, Michael; Wartzack, Sandro (Smart Product Engineering - Proceedings of the 23rd CIRP Design Conference, 2013)
UnivIS-Import:2015-04-16:Pub.2013.tech.FT.FT-KLMEFK.statis

Statistische Analyse der Auswirkungen von Fertigungsabweichungen auf den Druckwinkel von Axial-Schrägkugellagern - Aschenbrenner, Alexander (1. Summer School Toleranzmanagement, 2013)
Keywords: Statistische Toleranzanalyse; Toleranz; Schrägkugelager; Druckwinkel

Statistische Toleranzanalyse additiv gefertigter montagefreier Mechanismen unter Berücksichtigung von Gelenkspiel - Schächtl, Paul; Schleich, Benjamin; Wartzack, Sandro (Summer School Toleranzmanagement - Beiträge zur 4. Summer School - September 2020, 2020)

Statistische Toleranzanalyse mithilfe von Familientabellen-basierten Skelettmodellen - Winkler, Andreas (Beiträge zur 3. Summer School - September 2017, 2017)
Keywords: Summer School; Toleranzmanagement; Toleranzanalyse; Statistische Toleranzanalyse; Geometrische Produktspezifikation; Skelettmodelle

Statistische Toleranzanalyse verknüpfter Schließmaße - Heling, Björn; Aschenbrenner, Alexander; Wartzack, Sandro (Summer School Toleranzmanagement - Beiträge zur 2. Summer School - September 2015, 2015)

Statistische Toleranz-Kosten-Optimierung mit diskreten Toleranzwerten und mehrstufigem Kostenmodell - Hallmann, Martin (Summer School Toleranzmanagement - Beiträge zur 3. Summer School - September 2017, 2017)
Keywords: Toleranz-Kosten-Optimierung; Latin-Hypercube-Sampling

Status and Prospects of Skin Model Shapes for Geometric Variations Management - Schleich, Benjamin; Anwer, Nabil; Mathieu, Luc; Wartzack, Sandro (Procedia CIRP, Volume 43, 2016)
Geometric part deviations, which are inevitably observed on every manufactured workpiece, have distinct effects on the assemblability as well as on the function and quality of physical artefacts. As a consequence, geometric variations management is an important issue for manufacturing companies. However, assessing the effects of form deviations already in virtual product realization remains an important challenge. This paper illustrates and summarizes the current status and development trends of the Skin Model Shape paradigm, which provides an operationalization and a digital representation of the Skin Model concept for modelling product shape variability and hence may serve as a comprehensive model for computer-aided variations management.
Keywords: Computer-Aided Tolerancing; Skin Model Shapes; Geometric Variations Management; Virtual Product Realization

Steigerung der Bauteilqualität durch Erhöhung der Anlagensteifigkeit eines FDM-Druckers - Hallmann, Martin; Sprügel, Tobias; Kelber, Vincent; Schleich, Benjamin; Wartzack, Sandro (Konstruktion, 2018)
Die Qualität 3D-gedruckter Bauteile ist von einer Vielzahl an Einflussparametern abhängig. Nach Identifikation der Haupteinflussparameter auf die relevante Zielgröße, wie z. B. Maß- und Formhaltigkeit, mechanischen Eigenschaften oder Optik, können geeignete Maßnahmen dabei helfen, die Anforderungen an das 3D-gedruckte Bauteil zu erfüllen. Der nachfolgende Beitrag zeigt am Beispiel des Bausatz-Druckers Anet A8, dass neben den Prozessparametern der mechanische Aufbau des Druckers einen erheblichen Einfluss auf die Bauteilqualität hat.

Strain measurement on rolling bearings using sensors applied by aerosol-based deposition - Bartz, Marcel; Häußler, Felix; Halmos, Fabian; Ankenbrand, Markus; Jüttner, Michael; Franke, Jörg; Wartzack, Sandro (Bearing World, 2024)

Strength Analysis of Structurally Optimized Aluminium-Composite Tubular Lap Joints - Jäger, Michael; Wartzack, Sandro (Proceedings of the Design Society, 2022)
Truss structures are a stiff, economical, and efficient lightweight design, the limiting factor of these structures are usually the load transfer elements. This paper presents an analytical design method for optimized adhesive tubular lap joints between CFRP tubes and aluminium inserts. The analytically optimized design agrees very well with the numerical simulations and experimental results. Although the experiments show a highly non-linear behaviour, where a linear elastic correlation is expected, the total load capacity is only reached when the adhesive is fully plasticised.<br
Keywords: lightweight design; design optimisation; tubular lap joint; experimentation; composites

Strength Mapping Algorithm (SMA) for Biomechanical Human Modelling using Empirical Population Data - Miehling, Jörg; Wartzack, Sandro (Proceedings of the 20th International Conference on Engineering Design (ICED15), Vol. 10: Design Information and Knowledge Management, 2015)
Despite the increasing level of detail in biomechanical simulation, human models are not yet valid to represent specific individuals or populations. Therefore, the generic models need adaptation to depict the varying competencies of the respective person or user group aimed to investigate. There have been achievements in scaling single modelling domains (e.g. anthropometry). However, a comprehensive approach is still lacking. This paper extends available methods by introducing a Strength Mapping Algorithm (SMA) for the adaption of individual maximum isometric forces to match empirical strength data. This procedure involves static optimization simulation of predefined body postures to reveal the dependencies between muscle forces and joint torques of a generic model specifying the skeletal and muscular geometry. Based on this information, we determine a set of muscle scaling factors for a given age, gender and strength percentile. As a result, the SMA enables the quick generation of a large number of individuals in order to implement a design for populations paradigm. This leads one step closer to gain deeper insight on how health relevant products and processes are to be developed.
UnivIS-Import:2015-10-26:Pub.2015.tech.FT.FT-KLMEFK.streng
Keywords: User centred design; Human factors engineering; Simulation; Virtual engineering (VE); Strength percentiles

Structural Mechanics Analysis Using an FE-Mesh Adaption to Real, 3D Surface Detected Geometry Data - Katona, Sebastian; Sprügel, Tobias; Koch, Michael; Wartzack, Sandro (Journal of Mechanics Engineering and Automation, 2015)
Within today’s product development process, various FE-simulations (finite element) for the functional validation of the desired characteristics are made to avoid expensive testing with real components. Those simulations are performed with great effort for discretization, use of simulations conditions, like taking different non-linearities (i.e., material behavior, etc.) into account, to create meaningful results. Despite knowing the effects of deformations occurring during the production processes, always the non-deformed design model of a CAD-system (computer aided design) is used for the FE-simulations. It seems rather doubtful that further refinement of simulation methods makes sense, if the real manufactured geometry of the component is not considered for in the simulation. For an efficient exploit of the potential of simulation methods, an approach has been developed which offers a geometry model for simulation based on the existing CAD-model but with integrated production deviations as soon as a first prototype is at hand by adapting the FE-mesh to the real, 3D surface detected geometry.
Keywords: FEA (finite element analysis); preprocessing; simulation; 3D surface detection; RE (reverse engineering)

Structured ergonomic guidance in early design phases by analysing the user-product interaction - Schröppel, Tina; Endreß, Felix; Köpken, Ina; Miehling, Jörg; Wartzack, Sandro (Ergonomics, 2021)
Gathering information for an early, proactive integration of ergonomic user requirements is challenging due to the unstructured character of available knowledge. Knowledge acquisition and processing is therefore costly and time-consuming. This contribution presents and evaluates InProCo, an approach for structured ergonomic guidance that aims to improve accessibility and clarity of ergonomic requirements in early design phases by providing interaction-based ergonomic properties. InProCo reduces the complexity of gathering knowledge and provide a novel way to describe interactions. Within a three-stage evaluation process, a survey assessed standard interactions for completeness, the output given by the graphical user interface of the approach (GUI) was evaluated for correctness and the knowledge base was validated by comparing the approaches output with properties identified by participants within a one-day workshop. The results showed that there are enough predefined standard interactions, the output of the GUI is valid and the knowledge base contains high quality data
Keywords: User-product interaction; early design stages; ergonomic requirements; knowledge base; ergonomics methods in design

Strukturmechanische Simulation additiv im FFF-Verfahren gefertigter Bauteile - Völkl, Harald; Mayer, Johannes; Wartzack, Sandro (Konstruktion für die Additive Fertigung 2019, 2020)
Additive Fertigung ist zum etablierten Prozess geworden. Durch schichtweisen Aufbau werden nicht mehr nur Prototypen gefertigt, sondern auch Bauteile mit hohen Steifigkeits- und Festigkeitsanforderungen. Im Fused Filament Fabrication (FFF)-Verfahren gefertigte Bauteile werden schichtweise durch Extrusionspfade aufgebaut und besitzen in Pfadrichtung üblicherweise bessere mechanische Eigenschaften als quer dazu. Unterschiedliche Extrusionspfade, insbesondere im Bauteilinneren („Infills”) besitzen daher einen hohen Einfluss auf die mechanischen Bauteileigenschaften. Um diese bereits vor der eigentlichen Fertigung abschätzen zu können, wurde ein Simulationsansatz entwickelt, der ausgehend von Fertigungsinformation (G-code) ein Simulationsmodell aufbaut, welches die lokal unterschiedlichen Materialorientierungen berücksichtigt. Dieser Ansatz soll detailliert vorgestellt und anhand eines Demonstratorbauteils mit unterschiedlichen Infill-Mustern angewandt werde
Keywords: Leichtbau; Additive Fertigung; Simulation; Fused Filament Fabrication

Subject-specific tribo-contact conditions in total knee replacements: a simulation framework across scales - Rothammer, Benedict; Wolf, Alexander; Winkler, Andreas; Schulte-Hubbert, Felix; Bartz, Marcel; Wartzack, Sandro; Miehling, Jörg; Marian, Max (Biomechanics and Modeling in Mechanobiology, 2023)
Fundamental knowledge about in vivo kinematics and contact conditions at the articulating interfaces of total knee replacements are essential for predicting and optimizing their behavior and durability. However, the prevailing motions and contact stresses in total knee replacements cannot be precisely determined using conventional in vivo measurement methods. In silico modeling, in turn, allows for a prediction of the loads, velocities, deformations, stress, and lubrication conditions across the scales during gait. Within the scope of this paper, we therefore combine musculoskeletal modeling with tribo-contact modeling. In the first step, we compute contact forces and sliding velocities by means of inverse dynamics approach and force-dependent kinematic solver based upon experimental gait data, revealing contact forces during healthy/physiological gait of young subjects. In a second step, the derived data are employed as input data for an elastohydrodynamic model based upon the finite element method full-system approach taking into account elastic deformation, the synovial fluid’s hydrodynamics as well as mixed lubrication to predict and discuss the subject-specific pressure and lubrication condition
Keywords: Total knee replacement; Biomechanics; Biotribology; Multiscale simulation; In silico modeling

Subjektive Adaptionsfähigkeit im Kontext der alternssensiblen Produktentwicklung - Kamin, Stefan; Luft, Thomas; Miehling, Jörg; Williger, Bettina; Lang, Frieder; Wartzack, Sandro (Proceedings of the 25th Symposium Design for X, 2014)
Successful user involvement in user-centered product development should consider the motivational differences of older adults. We explored the influence of motivation when evaluating new technological products. We report findings based on the Subjective Technology Adaptivity Inventory – a measure of inter-individual differences in the motivation to use technology. Older adults participated in focus groups over a period of one year. Sessions involved the subjective evaluation of different technological products. Findings suggest that subjective technology adaptivity was associated with higher perceived usefulness of products. This association was stronger with increasing age. We discuss the findings with regard to the development of technological products for older adult
Keywords: User-centered product development; user involvement; aging; subjective technology adaptivity inventory

Supporting early robust design for different levels of specific design knowledge – An adaptive method for modeling with the Embodiment Function Relation and Tolerancing model - Li, Jiahang; Horber, Dennis; Grauberger, Patric; Götz, Stefan; Wartzack, Sandro; Matthiesen, Sven (Design Science, 2024)
Early robust design can lead to significant cost savings in the later stages of product development. In order to design systems that are insensitive to various sources of deviation in the early stages, specific design knowledge (SDK) plays a crucial role. Different design situations result in higher or lower levels of derivable SDK, which leads to different activities to achieve the development goal. Until now, no method has been developed to consider the different levels of derivable SDK from various design situations for early robustness evaluation. To address the problem, this paper outlines an adaptive modeling method using the Embodiment Function Relation and Tolerance (EFRT) model. The method is developed in two contrasting design situations, each with a high and low level of derivable SDK, and evaluated in another two corresponding case studies. It has a consistent structure with five stages and gates. At each stage, the derivable SDK is taken into account and the individual modeling steps are adapted. This method provides design engineers with concrete support for early robustness evaluation of a product concept in different development scenario
Keywords: design methods; product development; robustness evaluation; design situation; design knowledge

Surface modifications for adaption of tribological conditions in sheet-bulk metal forming processes - Löffler, Maria; Andreas, Kolja; Engel, Ulf; Weikert, Tim; Tremmel, Stephan; Wartzack, Sandro; Stangier, Dominic; Tillmann, Wolfgang; Merklein, Marion (Proceedings THE "A" Coatings, 2016)
Keywords: Sheet-bulk metal forming; Coatings; Friction

Symbol Detection in Mechanical Engineering Sketches: Experimental Study on Principle Sketches with Synthetic Data Generation and Deep Learning - Bickel, Sebastian; Götz, Stefan; Wartzack, Sandro (Applied Sciences, 2024)
Digital transformation is omnipresent in our daily lives and its impact is noticeable through new technologies, like smart devices, AI-Chatbots or the changing work environment. This digitalization also takes place in product development, with the integration of many technologies, such as Industry 4.0, digital twins or data-driven methods, to improve the quality of new products and to save time and costs during the development process. Therefore, the use of data-driven methods reusing existing data has great potential. However, data from product design are very diverse and strongly depend on the respective development phase. One of the first few product representations are sketches and drawings, which represent the product in a simplified and condensed way. But, to reuse the data, the existing sketches must be found with an automated approach, allowing the contained information to be utilized. One approach to solve this problem is presented in this paper, with the detection of principle sketches in the early phase of the development process. The aim is to recognize the symbols in these sketches automatically with object detection models. Therefore, existing approaches were analyzed and a new procedure developed, which uses synthetic training data generation. In the next step, a total of six different data generation types were analyzed and tested using six different one- and two-stage detection models. The entire procedure was then evaluated on two unknown test datasets, one focusing on different gearbox variants and a second dataset derived from CAD assemblies. In the last sections the findings are discussed and a procedure with high detection accuracy is determined.
CRIS-Team Scopus Importer:2024-08-02
Keywords: deep learning; object detection; principle sketch; symbol detection

Symbolic Parametric Representation of the Area and the Second Moments of Area of Periodic B-Spline Cross-Sections - Denk, Martin; Jäger, Michael; Wartzack, Sandro (Applied Mechanics, 2023)
The calculation of moments of area is one of the most fundamental aspects of engineering mechanics for calculating the properties of beams or for the determination of invariants in different kind of geometries. While a variety of shapes, such as circles, rectangles, ellipses, or their combinations, can be described symbolically, such symbolic expressions are missing for freeform cross-sections. In particular, periodic B-spline cross-sections are suitable for an alternative beam cross-section, e.g., for the representation of topology optimization results. In this work, therefore, a symbolic description of the moments of area of various parametric representations of such B-splines is computed. The expressions found are then compared with alternative computational methods and checked for validity. The resulting equations show a simple method that can be used for the fast conceptual computation of such moments of area of periodic B-splines.
Keywords: B-spline; cross-section; beam; moments of area; parametric; symbolic; moments; area

Symposium „Design for X“ und Summer School Toleranzmanagement - Wartzack, Sandro; Schleich, Benjamin (WiGeP News, 2020)

Synthesis of Compliant Mechanisms for Shape Adaptation by means of a Modal Procedure - Hasse, Alexander; Campanile, Lucio Flavio (Proceedings of 19th International Conference on Adaptive Structures and Technologies 2008, 2008)
Conventional mechanisms provide a defined mobility, which express the number of degrees of freedom of the mechanism. This allows the system to be driven by a low number of control outputs. This property is kept in case of compliant mechanisms with lumped compliance, which are obtained by replacing the conventional hinges by solid state ones. Compliant mechanisms with distributed compliance have, in general, an infinite number of degrees of freedom and therefore cannot guarantee defined kinematics. In this paper, compliant mechanisms with selective compliance are introduced. This special class of compliant mechanisms joins the advantages of distributed compliance with the easy controllability of systems with defined kinematics. This task is accomplished by introducing a new design criterion based on a modal formulation. After having implemented this design criterion in an optimization formulation for a formal optimization procedure, mechanisms are obtained in which a freely chosen deformation pattern is associated with a low deformation energy while other deformation patterns are considerably stiffer. Besides the description of the modal design criterion and the associated objective function, an application example is shown.
Keywords: Compliant mechanisms; Morphing; Shape adaptation; Shape control

Synthesis of Compliant Mechanisms with defined kinematics - Hasse, Alexander; Franz, Michael; Mauser, Kristian (Proceedings of Microactuators and Micromechanisms (MAMM-2016), Ilmenau, Germany, October 5-7, 2016, 2017)
A mechanism is designed to transform forces and/or displacements from an input to one or multiple outputs. This transformation is essentially ruled by the kinematics, i.e. the defined ratio between input and output displacements. Although the kinematics forms the basis for the design of conventional mechanisms, some common approaches for the topology and shape optimization of compliant mechanisms do not explicitly include the kinematics in their optimization formulation. The kinematics is more or less an outcome of the optimization process. A defined kinematics can only be realized by iteratively adjusting process-specific optimization parameters within the optimization formulation. This paper presents an optimization formulation that solves the aforementioned problem. It bases on one of the authors former publications on the design of compliant mechanisms with selective compliance. The formulation is derived by means of an intensive workup of the design problem of compliant mechanisms. The method is validated for a common design example: a force inverter.
Keywords: Compliant Mechanism; Selective Compliance; Topology Optimization; Defined Kinematics

Synthesis of passive lightweight orthoses considering humanmachine interaction - Steck, Patrick; Scherb, David; Miehling, Jörg; Völkl, Harald; Wartzack, Sandro (DS 119: Proceedings of the 33rd Symposium Design for X (DFX2022), 2022)
With increasing age, the probability of neurological diseases such as strokes, cancers, meningitis and Parkinson’s also increase. A stroke, for instance, often leads to damage to the central nervous system and therefore subsequent problems within the musculoskeletal system occur. Such movement restrictions are currently treated with the help of orthoses. However, commercial passive orthoses have the disadvantage that not all functions are covered, e. g. supporting all phases of the gait cycle. Full functionality can only be ensured with heavier active orthoses. The aim of this contribution is to develop a new hybrid user-centered/lightweight-design approach with which fully functional, passive lightweight orthoses can be designed and developed effectively in the future. Therefore, the methodology according to PAHL/BEITZ is expanded by including user-specific functions and attributes. The developed approach is applied on an ankle-foot-orthosi

Synthesis of planar compliant mechanisms with selective compliance for shape adaptation - Hasse, Alexander (Friedrich-Alexander-Universität Erlangen-Nürnberg, 2011)
In many technical problems, e.g. the shape adaptation of wings or rotor blades, it is desired that the changing of the structure's shape is smooth in order to operate as eciently as possible. Even where loads are not exactly predictable, a defined shape is required. Nevertheless, the complexity of the actuator system and of the mechanics should be as low as possible. It is within this context that this thesis presents the concept and the synthesis of compliant mechanisms with selective compliance. In contrast to classical mechanisms, which realize their motion through classical joints (e.g. bearings), compliant mechanisms use the deformability of the material to produce a particular movement. They therefore present several advantages, ranging from the absence of wear and backlash, to lower noise levels, clean operation, easier maintenance and reduced manufacturing eort. In addition, the deformation is not constrained to the joint areas, as in the case of a classical mechanism, rather it can be distributed continuously over the structure - this is advantageous in terms of a smooth shape adaptation. However, the kinematic behavior of compliant mechanisms is mostly load-dependent, i.e. a large number of possible deformation patterns can be obtained by altering the load acting on the system. This is not the case with classical mechanisms, as they usually have a defined number of kinematic degrees of freedom. The compliant mechanisms with selective compliance presented in this thesis combine both of these advantages: their kinematics may include a distributed deformation and they are virtually constrained to a defined number of kinematic degrees of freedom. The aim of this study is to develop an automated design method for compliant mechanisms with selective compliance. In this context, the design requirements are identified and classified. A design criterion based on eigenvalues and eigenvectors is presented after a modal analysis of various compliant structures. In order to be able to determine the compliant mechanism by means of numerical structural optimization, a modal objective function is introduced, the minimization of which leads to a structure that meets the design criterion. The modal objective function is validated by dierent design tasks. A force-inverter problem is taken from literature and is subjected to the developed methods. In addition, structures are presented which have complex kinematics, including smooth surface deformations. Since the dawn of aviation, engineers have tried to design shape adaptive wings in order to improve the eciency of aircrafts at different flight conditions. Concepts using conventional mechanics turned out to be too heavy and too complex. The belt-rib concept is a new approach: the classical ribs, which define the shape of the wing, are replaced by so-called "belt ribs". These are compliant mechanisms with selective compliance, consisting of an outer belt and an inner stiening structure, which are virtually limited to one kinematic degree of freedom. The kinematics depicted by a belt rib show a defined profile change. So far, the realizable profile changes have been limited, due to the chosen inner stiening structure and the synthesis methods available. With the findings of this thesis, it is now possible to design belt ribs describing an arbitrary profile change. In this thesis, an example of this is given in the form of a rib belt whose profile can be adapted from a NACA 0012 to a NACA 2412.
Keywords: compliant mechanism; selective compliance; shape adaptation

Sysml 4 Digital Twins – Utilization of System Models for the Design and Operation of Digital Twins - Wilking, Fabian; Sauer, Christopher; Schleich, Benjamin; Wartzack, Sandro (Proceedings of the Design Society, 2022)
The implementation of Digital Twins has become a common task for many industrial companies to ensure a sufficient digitization of their products and maintain competitiveness. This results in the question of how to compensate additional effort caused by designing Digital Twins. With this paper, an approach for this compensation is presented by creating Digital Twin behaviour through utilizing SysML diagrams and directly derivate usable code from them for a further implementation. This offers a part solution of lowering the threshold for using MBSE and increasing its benefits.<br
Keywords: model-based systems engineering (MBSE); cyber-physical systems; systems engineering (SE); digital design; complex systems

Systematic development of load-path dependent FLM-FRP lightweight structures - Völkl, Harald; Wartzack, Sandro (Design Science, 2021)
Additive manufacturing offers a high degree of design freedom. When Design for Additive Manufacturing is conducted properly, lightweight potential can be exploited. This contribution introduces a novel design approach for the widespread fused layer modelling (FLM) technology when using orthotropic Fibre Reinforced Polymer filament. Its objective is to obtain stiff and strong load-path optimized FLM structures in a structured and algorithmic way. The approach therefore encompasses (1) build orientation optimization to consider weaker bonding between layers than intralayer; (2) topology optimization with orthotropic material properties to obtain favourable overall geometry and inner structure; (3) direct build path generation from optimized material orientation and alternatives to the direct generation and (4) simulation. The approach is demonstrated using a lift arm under multiple load cases and further demonstrator parts to show its general applicability. Lightweight potential of individual optimization steps and the influence of modifications contrasting general non-FLM-specific optimization are studied and discusse
Keywords: Lightweight Design; Additive Manufacturing; Fibre-Reinforced Plastics; Fused Layer Modelling; Structural Optimisation

Szenario-Analyse zur Digitalisierung und Automatisierung des Produktentwicklungsprozesses - Dworschak, Fabian; Küstner, Christof; Schleich, Benjamin; Wartzack, Sandro (Tagungsband 16. Gemeinsames Kolloquium Konstruktionstechnik, 2018)
The Federal Ministries of Economic Affairs and Energy, Transport and Digital Infrastructure and the Federal Ministry of the Interior presented the Digital Agenda 2014 - 2017 in August 2014. The catalogue of measures presented describes digital work with the help of modern IT technologies such as data mining (DM) and new development methods such as model-based systems engineering (MBSE). Until 2018, these technologies made their way into several large corporations and specialized IT companies. However, their distribution in small and medium-sized enterprises (SMEs) is still very low. This can be a major economic disadvantage for them, as the technologies are based on holistic approaches, such as systems-of-systems models and networking between customers and suppliers. The technology transfer project "Optimization-based design methodology in early phase of mechatronic product development (OptMePro)" of the European Regional Development Fund (EFRE) aims at developing methods and models for the integration of modern development methods and IT technologies for SMEs. In particular, this article presents a process model for a scenario analysis that enables SMEs to analyze their own product development process (PDP) regarding the current grade of digitization and automation. This process model characterizes the PDP, reveals automation potentials and finally suggests suitable measures for improvement. The process model is universally applicable, so that it meets the needs of as many SMEs as possible. In addition, the intermediate results of the procedure are clearly and comprehensibly visualized in order to guarantee their application in SMEs. Moreover, it ensures the individual identification of fields of action for machine learning processes, facilitates the integration of data-driven tools into modern product development processes and thus forms the basis for iterative digitization and automation of the PDP in SME
Keywords: Model-Based Engineering; Traceability; Digital Engineering

"Tailored Coatings" - Konstruieren von und Konstruieren mit Beschichtungen - Tremmel, Stephan; Hetzner, Harald; Sander, Thomas; Schulz, Edgar (Design for X - Beiträge zum 19. Symposium., 2008)
UnivIS-Import:2015-04-16:Pub.2008.tech.FT.FT-KLMEFK.tailor

Tailored Coatings – Zur Auslegung beschichteter Bauteile - Tremmel, Stephan; Wartzack, Sandro; Meerkamm, Harald (Konstruktion, 2009)
Im Fahrzeug- und im Maschinenbau werden Komponenten zunehmend höher beansprucht. Dies gilt sowohl für die Bauteile selbst als auch für ihre Oberflächen. Sich kontaktierende Oberflächen stellen oft bestimmende Wirkflächenpaare dar (Zahnflanken, Nocke/Tassenstößel). Es ist daher konsequent, gezielt die Leistungsfähigkeit der Oberflächen zu steigern, um Wirkungsgrad oder Lebensdauer technischer Systeme zu erhöhen. Seit einigen Jahren kommen tribologische PVD-/PACVD-Schichten, v. a. DLC-Schichten, zum Einsatz. Diese erlauben die gezielte Adaption der Oberfläche auf die Anwendung. Man kann also von maßgeschneiderten Beschichtungen (Tailored Coatings) reden.
UnivIS-Import:2015-03-09:Pub.2009.tech.FT.FT-KLMEFK.tailor
Keywords: DLC; Auslegung; Kontaktspannungen; Mehrachsigkeit

Tailored Mechanical Properties and Residual Stresses of a-C:H:W Coatings - Schmid, Christoph; Hetzner, Harald; Tremmel, Stephan; Hilpert, Florian; Durst, Karsten (Advanced Materials Research, 2014)
In this study, three different a-C:H:W coatings with predefined hardness values, ranging from 10 up to 16 GPa, were deposited by selecting suitable parameter set points and adjusting substrate bias voltage of the reactive unbalanced magnetron sputtering process according to a previously created regression model. To obtain this model, the four main process parameters had been varied according to a central composite design and their influence on the mechanical properties of the a-C:H:W coating had been investigated previously by nanoindentation. The three coating variants of this study were investigated in terms of microstructure, mechanical properties and residual stresses. It turned out, that by the use of the regression model, indeed a-C:H:W coatings of tailored mechanical properties can be deposited. Residual stresses were measured by means of focused ion beam milling of a double-slit geometry, which causes the internal stresses to relax, and mapping of the resultant relief strain by digital image correlation. A nearly linear relation between the applied bias voltage and the hardness, the modulus of elasticity of the coating as well as the determined relief strain was observed. Thus, residual stresses of the coatings increase disproportionately with applied bias voltage. The obtained results can be helpful for tailored coating design and further optimization of a-C:H:W coating
UnivIS-Import:2015-03-09:Pub.2014.tech.FT.FT-KLMEFK.tailor
Keywords: a-C:H:W; Deposition parameters; Digital image correlation; Focused ion beam; Residual stress; Tailored properties

Tailored modifications of amorphous carbon based coatings for dry deep drawing - Merklein, Marion; Schmidt, Michael; Tremmel, Stephan; Andreas, Kolja; Häfner, Tom; Zhao, Rong; Steiner, Jennifer (Dry Metal Forming Open Access Journal, 2016)
Avoiding negative effects of conventional lubrication in forming operations stimulates research on lubricant-free sheet metal forming. Without lubricants, the direct contact between tool and workpiece leads to intensive interaction in terms of increasing friction and wear. Especially, when forming aluminum alloys, adhesion is detected as main wear mechanism propagating already at the initial contact between tool steel and sheet material. Thus, surface modifications need to be developed to substitute the functions of conventional lubricants. Former studies revealed that amorphous carbon based coatings improved the tribological conditions. Depending on the specific coating type adhesion and friction could be significantly reduced. Besides achieving a lower level of friction, a control of material flow is necessary to improve the forming results in deep drawing processes. Thus, there is a need for contact zones with higher and lower friction to locally accelerate or restrict the flow of the sheet material. In order to achieve these tailored tribological conditions a broad range of surface modifications needs to be developed and evaluated in a process-like environment. The tribological behavior is affected by coating properties and structure. By varying gas flow and ratio for a-C:H coatings the relationship between deposition parameters and coating properties are investigated. A further approach to realize a broader range of friction coefficients is the laser based texturing of coated tools. Additionally, a laser based heat treatment is investigated to control the sp2/sp3 ratio of ta-C coatings to affect friction and wear mechanisms. The tribological behavior of the investigated surface modifications is analyzed in ring-on-disc and flat strip drawing tests. A surface characterization is performed to identify about the wear mechanisms. Based on the modifications of a-C:H and ta-C coatings a correlation between chemical and mechanical properties and the tribological behavior in contact with zinc-coated deep drawing steel and aluminum alloys is found.
Keywords: Dry Deep Drawing; Tribology; Carbon Based Coatings; Laser Based Modification

Taking into account the change of geometry in system simulation processes. - Mauser, Kristian; Breitsprecher, Thilo; Wartzack, Sandro; Hasse, Alexander (DS 80-6 Proceedings of the 20th International Conference on Engineering Design (ICED 15) Vol 6: Design Methods and Tools-Part 2 Milan, Italy, 27-30.07.15, 2015)
In product development process of dynamic systems more than one technical field (i.e. mechanical, electrical or combustion technologies) affects the product. It is of particular importance to ensure the functionality of such multi-domain products especially after changing one of the domain-specific sub-process (i.e. CAD-data in mechanical design). This is possible by simulating the system behaviour of the overall product in a multi-domain system simulation. The consideration of the detailed information of each technical domain in the system simulation is not possible at moment. Therefore the relevant information in each sub-process have to be identified and insert into the system simulation. In this contribution focus is set on mechanical sub-process. An application is developed that identifies all changed information of a product design in the CAD-environment and provides this information to the system simulation. A proof of the functionality of the developed procedure in shown in a use case. The piston of a single-cylinder combustion engine model is changed by the designer. After that the developed application is executed and the changed simulation results are discussed.
Keywords: Systems Engineering (SE); Design Engineering; Design Process

Technisch-wirtschaftlicher Review der Herstellung tetraedrisch-amorpher Kohlenstoffschichten durch Lichtbogenverdampfen - Hetzner, Harald; Tremmel, Stephan; Meerkamm, Harald (Vakuum in Forschung und Praxis, 2009)
Wegen der hohen Energie der schichtbildenden Teilchen eignet sich Vakuumlichtbogenverdampfen zur Erzeugung tetraedrisch-amorpher Kohlenstoffschichten (ta-C). Da das Verfahren zudem hohe Abscheideraten erlaubt, erscheint es zunächst ideal, um ta-C auch in der industriellen Großserie herzustellen. Jedoch entstehen beim Verdampfungsprozess unweigerlich sog. Makropartikel, die auf den zu beschichtenden Bauteilen ebenfalls abgeschieden werden und die Schichteigenschaften erheblich verschlechtern. Es sind daher Maßnahmen erforderlich, die der Entstehung und/oder Abscheidung der Partikel entgegenwirken. Der folgende Artikel soll einen Überblick über mögliche Maßnahmen geben und diese mit Blick auf den Einsatz in der industriellen Großserienfertigung einer technisch-wirtschaftlichen Bewertung unterziehen. Due to the high energy of the depositing species, vacuum arc evaporation is suited for the production of tetrahedral-amorphous carbon coatings (ta-C). As besides, the process allows for high deposition rates, it seems to be ideal for the deposition of ta-C in industrial mass production. However, during the evaporation process inevitably macroparticles are formed, which also deposit on the parts to be coated, degrading the coating properties considerably. Therefore, measures are necessary in order to counter the formation and/or deposition of these particles. The following article intents to give an overview of possible measures and to subject them to a technical and economical evaluation in regard to their application in industrial mass production.
UnivIS-Import:2015-03-09:Pub.2009.tech.FT.FT-KLMEFK.techni
Keywords: ta-C; Makropartikel; Kathodenbrennflecksteuerung; Gepulste Arc-Kathode; HCA-Verdampfer; Laser-Arc-Modul; hochporöses Target; verteilter Lichtbogen; Rotierendes Target; Plasmafilter; Sputterätzen; Technisch-wirtschaftliche Bewertung

Teilprojekt 1: Virtuelle und experimentelle Toleranzuntersuchungen abweichungsbehafteter Baugruppen - Bode, Christoph; Schleich, Benjamin; Wartzack, Sandro (Abschlussbericht DFG-Forschungsgruppe FOR 2271, 2. Phase. Prozessorientiertes Toleranzmanagement mit virtuellen Absicherungsmethoden, 2023)

Temperature Behavior of Rolling Bearings Exposed to Centripetal Acceleration - Hochrein, David; Tremmel, Stephan; Wartzack, Sandro (Bearing World International Bearing Conference The Expert Forum for Bearings - Rolling and Plain Bearings!, 2018)
Rolling bearings which are operating under the influence of high centripetal accelerations are often subjected to enormous requirements. Beside the nominal lifetime and the arising frictional moment, the bearing temperature – an important factor for the achievable operating life of such bearings – is also a crucial aspect for the feasibility of rolling element bearings in the context of great accelerations. For this purpose the bearing temperatures in and outside of the load zone were measured during several tests in the acceleration field. The evaluation of the measurement results shows, among further findings, that the bearing load does not necessarily have a big influence on the temperature with bearings under the influence of centripetal acceleration
Keywords: rolling element bearings; centripetal acceleration; temperature behavior

Testing the Generalizability of Deep Learning Based Plausibility Detection with Unknown Finite Element Simulations - Bickel, Sebastian; Götz, Stefan; Wartzack, Sandro (DS 130: Proceedings of , Reykjavik, Iceland, 12th - 14th August 2024, 2024)
Shorter development times and greater product variety are necessary in the current business world. These challenges can be managed with virtual testing methods, but these require experienced engineers. To counteract the shortage, a data-driven plausibility detection was developed. The plausibility is determined with Deep Learning models that are trained on existing simulations. The practical application requires the models to work with simulations not included in the training data. Therefore, this paper analyzes the transferability of a plausibility detection model to new, unknown instance
Keywords: Artificial Intelligence (AI); Data Driven Design; Structural Analysis; Deep Learning; Finite Element Simulation

The balance between a usable and emotional product design – a comparison of different methods for prioritising relevant influencing factors - van Remmen, Judith Sophie; Horber, Dennis; Händel, Jonas; Miehling, Jörg; Wartzack, Sandro (DESIGN 2024, 2024)
Designing an equally usable and emotionally appealing product remains a challenge for product developers, not least due to conflicting goals. Product developers need to constantly map the affective user requirements to the product, whereby the requirements for the emotional and usable product design often cannot be equally addressed. The systematic approach presented can help product developers in conflicting decision-making situations to represent these affective user requirements by selecting and prioritising context-relevant influencing factors using multi-criteria decision-making methods.<br
Keywords: user-centred design; emotional engineering; user experience; decision making

The Balance Between a Usable and Emotional Product Design - A Concept for Prioritising Relevant Influencing Factors - van Remmen, Judith Sophie; Horber, Dennis; Miehling, Jörg; Wartzack, Sandro (Proceedings of the 34th Symposium Design for X (DFX2023), 2023)
Usability and emotionality represent fundamental aspects of user experience. Yet designing an equally usable and emotionally appealing product remains a challenge for product developers, not least due to conflicting goals. Product developers need a deep understanding of what is important to users in different situations of use to make a user-oriented decision between a more usable or emotionally appealing product design. To support product developers in conflicting decision-making situations, the presented systematic approach for the selection and prioritization of context-relevant influencing factors can contribute. By mapping influencing factors and the prioritization using decision theory methods, the importance of the influencing factors in different usage scenarios can be identifie
Keywords: Usability; emotional design; user experience; user-centred design; decision making

The challenge of handling material information from different sources - Krehmer, Hartmut; Wartzack, Sandro; et al. (Proceedings of the 18th International Conference on Engineering 2011 (ICED 11), 2011)
Nowadays there are a lot of different kinds of material information needed in the product development process. This article will analyze the challenge of handling material information from different sources and different phases in the development process of the automotive industry. The needs for various kinds of material information are analyzed by different subjects (legislative regulations, construction design, strategically requirements). The information sources are examined in order to understand the differences and the reasons for the difficulties that occur when integrating the material information into the systems and sources. As a result the main problem will be identified, which is the different semantics or naming of the materials. Two possible solutions to overcome the difficulties and to make the available information accessible are evaluated and compared. These approaches are a data warehouse and an intelligent search engine. On the basis of the evaluation the search engine approach will be identified as the preferred one. While a more sufficient solution to solve the problem of the many sources is presented, this article also provides a solution to overcome the problem of the different semantics. Copyright © 2002-2012 The Design Society. All rights reserved.
UnivIS-Import:2015-04-16:Pub.2011.tech.FT.FT-KLMEFK.thecha
Keywords: Heterogeneous systems; Integrating material information; Material information; Semantic problems

The Determination of Assistance-as-Needed Support by an Ankle–Foot Orthosis for Patients with Foot Drop - Scherb, David; Steck, Patrick; Wechsler, Iris; Wartzack, Sandro; Miehling, Jörg (International Journal of Environmental Research and Public Health, 2023)
Patients who suffer from foot drop have impaired gait pattern functions and a higher risk of stumbling and falling. Therefore, they are usually treated with an assistive device, a so-called ankle–foot orthosis. The support of the orthosis should be in accordance with the motor requirements of the patient and should only be provided when needed, which is referred to as assistance-as-needed. Thus, in this publication, an approach is presented to determine the assistance-as-needed support using musculoskeletal human models. Based on motion capture recordings of multiple subjects performing gaits at different speeds, a parameter study varying the optimal force of a reserve actuator representing the ankle–foot orthosis added in the musculoskeletal simulation is conducted. The results show the dependency of the simulation results on the selected optimal force of the reserve actuator but with a possible identification of the assistance-as-needed support required from the ankle–foot orthosis. The required increase in support due to the increasing severity of foot drop is especially demonstrated with the approach. With this approach, information for the required support of individual subjects can be gathered, which can further be used to derive the design of an ankle–foot orthosis that optimally assists the subjects.<br
Keywords: ankle–foot orthosis; digital human models; gait assistance; musculoskeletal simulation; foot drop; muscle weakness; design for medical devices

The evolution of knowledge-based engineering from a design research perspective: Literature review 2012–2021 - Kügler, Patricia; Dworschak, Fabian; Schleich, Benjamin; Wartzack, Sandro (Advanced Engineering Informatics, 2023)
Knowledge-based engineering (KBE) is a research field, which evolved in the 1980s within the context of artificial intelligence (AI), computer aided design (CAD) and computer programming. KBE is often referred to methods, processes and tools for knowledge reuse and design automation promising time and cost benefits in engineering design and originally especially in aerospace and automotive industry. Despite the long period of existence, theoretical foundations of KBE are weak and scientific literature is quite dispersed. About a decade ago, a review by Verhagen et al. collected the state of research and identified future research challenges, which has gained impact within the KBE research community. Therefore, within our review we aim at analysing the evolution of those research challenges in KBE literature during the last decade and further provide an overview of current shortcomings from a design research perspective. The analysis comprises 160 publications from the period of 2012 to 2021. Key findings from the review show, that the challenges from 2012 remain unsolved. We further derived that reuse and adoption of KBE approaches from literature is impeded by (1) a missing conceptualization of KBE research, (2) insufficient links from knowledge source to automation and (3) a tendency of insufficient distinction of the application area.
CRIS-Team Scopus Importer:2023-02-10
Keywords: Design automation; Engineering design; KBE; Knowledge engineering; Knowledge-based engineering; Review

The Gaul resonator: Experiments for the isolated investigation of a bolted lap joint - Süß, Dominik; Janeba, Anton; Willner, Kai (Springer International Publishing, 2017)
CRIS-Team Scopus Importer:2022-08-05

The Implications of the Skin Model Concept for Computer Aided Tolerancing - Schleich, Benjamin; Wartzack, Sandro (Smart Product Engineering, 2013)
During product origination many deviations occur which manifest in unreliable functional behaviour and reduced product quality. Thus, the observable geometric deviations have to be limited by geometric tolerances of function-relevant part features. In this context the standards for Geometrical Product Specification and Verification (GPS) provide helpful tools for geometric tolerancing. A basic concept within these standards is the skin model concept which can be understood as a model of the physical interface between the workpiece and its environment. Recent research tries to translate this concept into discrete geometry and focuses upon the technical aspects related to generating skin model shapes, whereas the implications of this concept and emerging simulation possibilities for the geometric variations management process stay disregarded. Therefore, this paper highlights the consequences of the skin model concept and modern simulation tools for the computer aided tolerancing process and the management of geometric deviations during product development.
Keywords: Skin Model; Geometric Variations Management; Tolerance Management; Computer Aided Tolerancing

The influence of speed and load spectra on the friction of rolling bearings - Stahl, Thomas; Tremmel, Stephan; Meerkamm, Harald; Wartzack, Sandro (65th STLE Annual Meeting & Exhibition 2010, 2010)
UnivIS-Import:2015-04-16:Pub.2010.tech.FT.FT-KLMEFK.theinf

The Influence of the Centripetal Acceleration on the Temperature Behavior of Rolling Bearings - Hochrein, David; Tremmel, Stephan; Wartzack, Sandro (Bearing World Journal, 2018)
The bearing temperature is one of the essential variables in order to describe a bearing system. Especially under extreme conditions such as external accelerations, an unsuitable temperature development at the bearing position can cause significant damage. This work examines the temperature behavior under the influence of high centripetal accelerations up to 1 000- times gravity. Therefore, the factors centripetal acceleration, relative speed of the specimen and the oil flow rate were varied systematically. Contrary to our expectations, the temperature does not rise with an increase of the centripetal acceleration. This behavior can essentially be explained by the impact of the acceleration to the supplied oil flow rate. Therefore the increased injection speed of the lubricating and cooling oil leads to a better cooling of the roller bearings and the bearing temperature nearly remains constant. If the relative speed of the specimen increases, the bearing temperature behaves as with bearings, which are not exposed to the influence of high accelerations. E.g. the temperature rises, even if only moderate. The temperature behavior was analyzed and evaluated in the context of the present frictional moment. In order to achieve a sufficient cooling effect by the lubricating oil flow an appropriate amount of lubricant is necessary. The present investigation showed that with roller bearings exposed to centripetal accelerations the necessary amount of oil is about ten times higher than under normal circumstances. Appropriate flow rates depending on the requirements were identified by the variation of the oil flow rate. A look at the overall context shows that the bearing temperature is not an exclusion criterion for the use of roller bearings exposed to high accelerations. With an appropriate design of the oil supply also a self-regulation effect of the oil flow rate can be achieved by the present accelerations.<br
Keywords: roller bearings; centripetal acceleration; temperature behaviour; appropriate oil supply quantity

The Interplay of Subjective Quality Evaluation, Prototyping Technologies and the User's Technology Acceptance - Buker, Tina; Endreß, Felix; Miehling, Jörg; Wartzack, Sandro (Proceedings of the Design Society, 2022)
Subjective product quality is a fundamental aspect to maintain a high level of user acceptance and to provide a good user experience. Prototypes can be used to evaluate subjective product quality in early design phases. We conducted an empirical study to examine the influence of different (re)presentations of prototypes determined by the chosen technology (2D image, VR, AR, 3D print) and the user's technology acceptance. Based on the results we recommend 2D images as most reliable for evaluating subjective product quality.<br
Keywords: empirical studies; emotional engineering; prototyping; subjective quality; technology acceptance

The Load-Scanning Test Evaluation of a Universal Tribological Model Test in View of Sheet Bulk Metal Forming - Hetzner, Harald; Tremmel, Stephan; Wartzack, Sandro (Key Engineering Materials, 2012)
Combining the loading conditions of two different classes of forming operations, in sheet bulk metal forming processes, contact pressures ranging from a few hundred MPa up to loads exceeding 2,500 MPa are experienced. With the additional need for an enhanced control of the material flow, which is best implemented by locally adapted frictional properties of the contact tool/workpiece, sheet bulk metal forming represents a challenge to tribology. As a consequence, the evaluation of the friction and wear properties of different surface modifications and lubricants within a variety of loading conditions is required. The load-scanning test is a universal tribological model test. Its most distinctive feature is the ability to assess the friction and wear behaviour of a tribological pairing within a whole range of contact loads in a single test run. The simple and quick test method also allows the investigation of plastic contacts. Due to these features, the load-scanning test is of particular interest with regard to the quantitative and qualitative evaluation of the application potentials and limits of use of tribological measures intended for sheet bulk metal forming. Like any model test, the load-scanning test has also specific drawbacks. In some test setups, the stress distribution in the contact area may be non-uniform. Further, the maximum realizable contact pressure may be limited by low yield strengths of the tested materials in combination with the insufficient flow restriction of the contact geometry and/or the moderate machine force. By comparison to other test methods and by giving examples of its application in different scenarios, the present paper discusses the potentials and limitations of the load-scanning test against the background of sheet bulk metal forming.© (2012) Trans Tech Publications.
UnivIS-Import:2015-03-09:Pub.2012.tech.FT.FT-KLMEFK.theloa
Keywords: Forming tool tribology; Load-scanning test; Sheet bulk metal forming; Tribological model test

The realization of an engineering assistance system for the development of noise-reduced rotating machines - Küstner, Christof; Wartzack, Sandro (DS 80-4 Proceedings of the 20th International Conference on Engineering Design (ICED 15), 2015)
Today, product developer face the challenge taking not only the requirements for mechanical properties of a product into account, but also other requirements like the acoustical properties, for instance. If undesired acoustical product properties are identified product developer ask experts for counter-measures. They usually can find solutions for these acoustical issues by detailed analysis of data like sound emission measurements, noise and vibration measurements or validated multi-body simulation results. By aid of an engineering assistance system the knowledge of the expert can be provided to product developer in order to reapply these findings for new products or product variants already in early design phases of the product development process. This will help the product developer to guarantee the specified acoustical product properties already in the earlier phases. This contribution will give an insight in the realization of the engineering assistance system ALARM for the development of noise-reduced machines.
UnivIS-Import:2015-10-26:Pub.2015.tech.FT.FT-KLMEFK.therea
Keywords: Knowledge management; Early design phases; Product modelling; models; Design for X (DfX)

Thermodynamic and theoretical-based modeling and assessment of an energy-efficient performance measurement system in the soldering process - Esfandyari, Alireza; Kreitlein, Sven; Schmidt, Elias; Franke, Jörg (2016 Electronics Goes Green 2016+, EGG 2016, 2017)
This paper presents methods for the assessment and evaluation of two energy efficiency strategies for the soldering process in the field of electronics production. The first method evaluates the electrical energy consumption performance through the energy value modeling in the production process level. In the second method, also other energy resources rather the electrical energy consumption is considered. This method assesses the quality of resource conversion in the soldering process in the product level. In this paper, firstly, the system of the least energy demand as crossbench reference value is explained. The basic idea of this calculation is the comparison and evaluation of electrical energy efficiency based on the ratio of the theoretically required energy consumption to the measured electrical energy consumption. In the second method, the model quantifies the resource consumption and qualifies this consumption using the exergy analysis method. Exergy efficiency is the fraction of the work potential of the heat that is converted to work, and it illustrates the quality of consumed resources during the soldering process. Transparency and comparison of these two methods derives the measures to analyze and improve the major energy saving potentials in the soldering oven technology.
CRIS-Team Scopus Importer:2023-03-07

The role of product development in the battle against product-related stigma – a literature review - Schröppel, Tina; Miehling, Jörg; Wartzack, Sandro (Journal of Engineering Design, 2021)
Stigma may be the Achilles’ heel of Inclusive Design, having a variety of negative effects on the user, e.g. anxiety or depression. From a product development (PD) perspective, such negative user stigmatisation can lead to the rejection of a product. PD cannot defeat stigma itself, but it can make a valuable contribution by reducing product-related stigma. Joining the battle, this contribution analyses the role of PD and identifies supports that help to reduce stigma in the respective context using an initial and a systematic literature review. The role of PD is split into four categories addressing the need to fulfil specific demands (reduce stigma and improve personal well-being), exploit potentials (see design as a tool, use the power of product semantics and design for our future selves), solve current problems (lack of knowledge and not taking the user seriously) and manage boundary conditions (complexity of stigma and the stigma-sensitivity of products). Individual, process, educational solutions or general strategies are supports that help meeting those expectations. Due to different challenges, there is still a need for action to improve those supports to deliver specific design recommendations and reduce the lack of knowledg
Keywords: Inclusive Design; stigma; support; product design; systematic literature review

The Use of Artificial Intelligence in Tribology - A Perspective - Rosenkranz, Andreas; Marian, Max; Profito, Francisco J.; Aragon, Nathan; Shah, Raj (Lubricants, 2021)
Artificial intelligence and, in particular, machine learning methods have gained notable attention in the tribological community due to their ability to predict tribologically relevant parameters such as, for instance, the coefficient of friction or the oil film thickness. This perspective aims at highlighting some of the recent advances achieved by implementing artificial intelligence, specifically artificial neutral networks, towards tribological research. The presentation and discussion of successful case studies using these approaches in a tribological context clearly demonstrates their ability to accurately and efficiently predict these tribological characteristics. Regarding future research directions and trends, we emphasis on the extended use of artificial intelligence and machine learning concepts in the field of tribology including the characterization of the resulting surface topography and the design of lubricated systems.<br
Keywords: artificial intelligence; machine learning; artificial neural networks; tribology

The Value of Information in Clustering Dense Matrices: When and How to Make Use of Information - Endreß, Felix; Kipouros, T.; Buker, Tina; Wartzack, Sandro; Clarkson, P. J. (Proceedings of the Design Society, 2022)
Characterising a socio-technical system by its underlying structure is often achieved by cluster analyses and bears potentials for engineering design management. Yet, highly connected systems lack clarity when systematically searching for structures. At two stages in a clustering procedure (pre-processing and post-processing) modelled and external information were used to reduce ambiguity and uncertainty of clustering results. A holistic decision making on 1) which information, 2) when, and 3) how to use is discussed and considered inevitable to reliably cluster highly connected systems.<br
Keywords: cluster analysis; design structure matrix (DSM); socio-technical systems; dense matrices; design models

Thin Layers in the Automotive Industry as a Challenge for Design and Development - Meerkamm, Harald; Seitz, Alexander; Stahl, Thomas; Tremmel, Stephan (Book of Abstracts of the 34th International Conference on Metallurgical Coatings and Thin Films ICMCTF 2007, 2007)
UnivIS-Import:2015-04-16:Pub.2007.tech.FT.FT-KLMEFK.thinla
Keywords: Design for coating; Common rail injection systems; PVD-/PACVD carbon-based coatings; Surface texturing

Ti3C2Tx Solid Lubricant Coatings in Rolling Bearings with Remarkable Performance beyond State-of-the-Art Materials - Marian, Max; Feile, Klara; Rothammer, Benedict; Bartz, Marcel; Wartzack, Sandro; Seynstahl, Armin; Tremmel, Stephan; Krauß, Sebastian; Merle, Benoit; Boehm, Thomas; Wang, Bo; Wyatt, Brian C.; et al. (Applied Materials Today, 2021)
Two-dimensional (2D) transition metal carbides, nitrides, and carbonitrides, known as MXenes, are a growing class of 2D materials, which offer great solid lubrication ability for low friction applications due to their weakly bonded multi-layer structure and tribo-layer formation with self-lubricating characteristics. To date, most studies have assessed their tribological response in basic laboratory tests. However, these tests do not adequately reflect the complex geometries, kinematics, and stresses present in machine components. Here, we aim at bridging this gap through assessment of the friction and wear performance of multi-layer Ti3C2Tx MXene solid lubricant coatings used in rolling bearings. MXenes’ tribological response is compared with state-of-the art solid lubricant coatings, which include molybdenum disulfide (MoS2), tungsten-doped hydrogenated amorphous carbon (a‑C:H:W), and hydrogen-free, more graphite-like amorphous carbon (a‑C). Multi-layer Ti3C2Tx MXene coatings reduce wear on the bearing washers by up to 94 %, which can be attributed to the transfer of the lubricious MXene nano-sheets to secondary tribo-contacts of the bearing. While the frictional torque of all solid lubricant coatings is similar during steady-operation, the MXene-coated bearings extend the service life by 30 % and 55 % compared to MoS2 and DLC, respectively. This contribution demonstrates the ability of MXene solid lubricant coatings to outperform state-of-the-art solid lubricants in dry-running machine components such as rolling bearing
Keywords: 2D materials; MXenes; MoS2; DLC; solid lubrication; rolling bearings

Ti3C2Tx-UHMWPE nanocomposites—Towards an enhanced wear-resistance of biomedical implants - Rothammer, Benedict; Feile, Klara; Werner, Siegfried; Frank, Rainer; Bartz, Marcel; Wartzack, Sandro; Schubert, Dirk W.; Drummer, Dietmar; Detsch, Rainer; Wang, Bo; Rosenkranz, Andreas; Marian, Max (Journal of Biomedical Materials Research Part A, 2024)
There is an urgent need to enhance the mechanical and biotribological performance of polymeric materials utilized in biomedical devices such as load-bearing artificial joints, notably ultrahigh molecular weight polyethylene (UHMWPE). While two-dimensional (2D) materials like graphene, graphene oxide (GO), reduced GO, or hexagonal boron nitride (h-BN) have shown promise as reinforcement phases in polymer matrix composites (PMCs), the potential of MXenes, known for their chemical inertness, mechanical robustness, and wear-resistance, remains largely unexplored in biotribology. This study aims to address this gap by fabricating Ti3C2Tx-UHMWPE nanocomposites using compression molding. Primary objectives include enhancements in mechanical properties, biocompatibility, and biotribological performance, particularly in terms of friction and wear resistance in cobalt chromium alloy pin-on-UHMWPE disk experiments lubricated by artificial synovial fluid. Thereby, no substantial changes in the indentation hardness or the elastic modulus are observed, while the analysis of the resulting wettability and surface tension as well as indirect and direct in vitro evaluation do not point towards cytotoxicity. Most importantly, Ti3C2Tx-reinforced PMCs substantially reduce friction and wear by up to 19 and 44 %, respectively, which was attributed to the formation of an easy-to-shear transfer fil
Keywords: 2D materials; MXenes; UHMWPE; polymer matrix composites; biotribology

Time vs. Space: Comparing gait cycle normalization methods and their effect on foot placement control - Fleischmann, Sophie; Shanbhag, Julian; Miehling, Jörg; Wartzack, Sandro; Leyendecker, Sigrid; Koelewijn, Anne; Eskofier, Björn (28th Congress of the European Society of Biomechanics, 2023)

Tolerance Analysis of Additively Manufactured Non-assembly Mechanisms considering Joint Clearance - Schächtl, Paul; Hallmann, Martin; Schleich, Benjamin; Wartzack, Sandro (Procedia CIRP, 2020)
Besides numerous advantages, Additive Manufacturing enables the manufacturing of entire non-assembly mechanisms within one single process step. However, this requires comparatively large joint clearances that significantly influence their functionality. Existing tolerance analysis methods completely neglect or simplify these clearances and thus cannot adequately represent a realistic motion behavior. With the aim to overcome this drawback, this contribution presents a novel method for the statistical tolerance analysis of additively manufactured mechanisms. The integration of results from multi-body simulation enables a realistic representation of the movements within the joints. Finally, the exemplary application to a planar non-assembly mechanism shows, that the process-related large joint clearances have more significant influence than the part deviations.<br
Keywords: Additive ManufacturingTolerance AnalysisNon-assemblyJoint ClearanceMulti-body Simulation

Tolerance analysis of mechanism taking into account the interactions between deviations using meta-models - Walter, Michael; Sprügel, Tobias; Wartzack, Sandro (Proceedings of the 9th Norddesign, 2012)
A product’s functionality depends largely on the interaction of its components and their geometries. Hence, tolerance analyses are used to determine the effects of deviations on a functional key characteristic – also for mechanism. However, possible interactions between the different deviations and the resulting effects among themselves as well as on the functional key characteristics are not considered yet. This paper considers the extension of an existing “integrated tolerance analysis of systems in motion” approach in detail: The integration of meta-models, which represent the interactions, into the system’s functional relationship. Therefore different meta-modeling techniques as well as validation techniques are used. Consequently a recommendation can be derived, how the product developer can achieve a high prediction quality of the meta-models and therefore a reliable tolerance analysis of mechanism taking into account the appearing interactions.
UnivIS-Import:2015-04-16:Pub.2012.tech.FT.FT-KLMEFK.tolera
Keywords: tolerance analysis; mechanism; meta-modeling; data-mining; cross-validation

Tolerance Analysis of Rotating Mechanism Based on Skin Model Shapes in Discrete Geometry - Schleich, Benjamin; Wartzack, Sandro (Procedia CIRP, 2015)
Geometric deviations are inevitably observable on every manufactured workpiece. These deviations affect the function and quality of mechanical products and have therefore to be controlled by geometric tolerances. Computer-aided tolerancing aims at supporting design, manufacturing, and inspection by determining and quantifying these effects of geometric deviations on the product quality and the functional behaviour. However, most established tolerance representation schemes imply abstractions of geometric deviations and are not conform with the standards for geometric dimensioning and tolerancing. These limitations led to the development of a Skin Model inspired framework for the tolerance analysis, which is based on a representation of non-ideal workpieces employing discrete geometry representation schemes, such as point clouds and surface meshes. In this contribution, this Skin Model inspired framework for computer aided tolerancing is extended to systems in motion and applied to the tolerance analysis of rotating mechanism with higher kinematic pairs. For this purpose, the generation of non-ideal part representatives, as well as their processing with algorithms for registration and computational geometry are highlighted. Finally, the results are visualized and interpreted. The procedure as well as the simulation model itself are shown in a case study of a disk cam mechanism.
UnivIS-Import:2015-10-26:Pub.2015.tech.FT.FT-KLMEFK.tolera
Keywords: Skin Model; Tolerance Analysis; Rotating Mechanism; Discrete Geometry; Computational Geometry

Tolerance analysis of systems in motion taking into account interactions between deviations - Walter, Michael; Sprügel, Tobias; Wartzack, Sandro (Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture, 2013)
A product's functionality depends largely on the interaction of its components and their geometries. Hence, tolerance analyses are used to determine the effects of deviations on functional key characteristics of mechanisms. However, possible interactions between the different deviations and the resulting effects on themselves as well as on the functional key characteristics have not yet been considered. This article considers the extension of the existing "integrated tolerance analysis of systems in motion" approach. By means of the methodology, the interactions between appearing deviations can be identified and integrated into a tolerance analysis functional relation. Therefore, the appearing interactions are represented by meta-models that can be easily integrated into the functional relation. Consequently, the product developer is able to gain information about the effects of deviations on functional key characteristics, as well as the effects of the deviations among themselves. In order to show the methodology's practical use, the interactions between deviations of a nonideal crank mechanism inside a four-stroke combustion engine are considered. For this purpose, two different meta-modeling techniques are used: response surface methodology and artificial neural networks. © IMechE 2012.
UnivIS-Import:2015-03-09:Pub.2013.tech.FT.FT-KLMEFK.tolera
Keywords: Artificial neural networks; Interactions; Meta-modeling; Systems in motion; Tolerance analysis

Tolerance-Cost-Optimization of Systems with time-variant Deviations - Walter, Michael; Sprügel, Tobias; Wartzack, Sandro (Proceedings of the 13th CIRP Conference on Computer Aided Tolerancing, 2014)
This paper presents a methodology for the statistical tolerance-cost-optimization of systems with time-variant deviations, such as deformation, thermal expansion, mobility of parts and wear. By means of the approach, the product developer can identify the system’s optimal tolerance design against the backdrop of the diverging requirements: wide tolerances to reduce costs vs. narrow tolerances to ensure functionality. Therefore, Particle Swarm Optimization – a global statistical optimization technique – is applied to the time-variant tolerance-optimization problem to determine the tolerance range as well as a certain mean shift for each non-ideal dimension. The practical use of the methodology is illustrated for a modified tolerance stack-up problem. We provide a comprehensive walkthrough of the methodology’s application to the stack-up problem. Therefore, the essential mathematical background, the required functional dependencies and the considered parameters are detailed in a step-by-step procedure. So, we aim to establish the application of the statistical tolerance-cost-optimization in academia and industry and to motivate students and young graduates to apply this methodology by themselves.
UnivIS-Import:2015-04-16:Pub.2014.tech.FT.FT-KLMEFK.tolera
Keywords: tolerance synthesis; time-dependent mechanisms; deformation; thermal expansion; particle swarm optimization

Tolerance management during the design of composite structures considering variations in design parameters - Franz, Michael; Schleich, Benjamin; Wartzack, Sandro (International Journal of Advanced Manufacturing Technology, 2021)
Composite structures play an important role in realising resource-efficient products. Their high lightweight potential and improved manufacturing technologies lead to an increased use in high-volume products. However, especially during the design and development of high-volume products, the consideration of uncertainties is essential to guarantee the final product quality. In this context, the use of modern lightweight materials, such as fibre reinforced plastics (FRP), leads to new challenges. This is due to their high number of design parameters, which are subject to deviations from their nominal values. Deviating parameters, e.g. ply angles and thicknesses, influence the manufacturing process as well as the structural behaviour of a composite part. To consider the deviating design parameters during the design process, a new tolerance optimisation approach is presented, defining tolerance values for laminate design parameters, while ensuring the functionality of the composite structure. To reduce the computational effort, metamodels are used during this optimisation to replace finite element simulations. The proposed approach is applied to a use case with different key functions to show its applicability and benefit
Keywords: Composite structures; Tolerance optimisation; Metamodel; Endless fibre reinforced plastics

Tolerance Optimization for Composite Structures - Franz, Michael; Freitag, Stephan; Wartzack, Sandro (Research in Tolerancing, 2024)
With rising demands and regulations for efficient and sustainable products, the use of high performance composite materials rises. There are a large number of manufacturing processes for composite materials, which inevitably lead to variations. Consideration of variations during product development is therefore particularly important for products of larger quantities. For this reason, this publication analyzes the variations and then applies methods from tolerance management to take them into account. Therefore, an approach for tolerance analysis and optimization is presented, with which the tolerance ranges of varying laminate parameters are analyzed and optimized. With this approach, not only one design parameter can be optimized, but it enables the simultaneous optimization of different parameter types like ply angle or ply thickness. Furthermore, surrogate models are used to reduce the computational effor

Tolerance Optimization of Patch Parameters for Locally Reinforced Composite Structures - Franz, Michael; Wartzack, Sandro (Applied Composite Materials, 2022)
A rising number of applications and increasing volume of composite structures production lead to a high relevance of variation management during their design. Structural optimization for lightweight purposes often results in designs consisting of a base laminate with local reinforcement patches. Nominally, these optimized designs offer a thorough exploitation of lightweight potential. Yet, they suffer from variations of the reinforcements resulting in a worsened manufacturing behavior and reduced structural performance. To ensure the quality, tolerances should be allocated for the parameters of the local reinforcement patches. Therefore, in the current contribution a tolerance optimization method is presented identifying optimal tolerance values for the design parameters of the reinforcements with respect to the structural behavior. This includes the discussion of challenges regarding the suitable parametrization and modeling of local reinforcement patches for variation simulation based on Finite Element Analysis (FEA), the usage of surrogate modeling to reduce the computational effort of structural analyses, as well as an approach to penalize tight tolerances of different parameter types. The proposed tolerance optimization is applied to a use case. Tolerances for the patch parameters are optimized, meeting the structural quality constraints of the composite structure.
CRIS-Team Scopus Importer:2022-10-21
Keywords: Composite structures; Local reinforcement; Surrogate modeling; Tolerance optimization

Tolerancing Informatics: Towards Automatic Tolerancing Information Processing in Geometrical Variations Management - Schleich, Benjamin; Anwer, Nabil (Applied Sciences, 2021)
The management of geometrical variations throughout the product life cycle strongly relies on the gathering, processing, sharing and dissemination of tolerancing information and knowledge. While today, this is performed with many manual interventions, new means for automatic information processing are required in future geometrical variations management to make full use of new digitalization paradigms, such as industry 4.0 and digital twins. To achieve this, the paper proposes the term tolerancing informatics and investigates new concepts and means for automatic information processing, novel information sharing workflows as well as the integration of tools for next generation geometrical variations management. In this regard, the main aim of the paper is to structure existing tolerancing informatics workflows as well as to derive future research potentials and challenges in this domain. The novelty of the paper can be found in providing a comprehensive overview of tolerancing informatics as an important enabler for future geometrical variations managemen
Keywords: Tolerancing; Information; Design

Tolerancing in product design – a holistic description scheme - Götz, Stefan; Roth, Martin; Schächtl, Paul; Kramer, Vincent; Bode, Christoph; Horber, Dennis; Franz, Michael; Freitag, Stephan; Miehling, Jörg; Wartzack, Sandro (Design Science, 2025)
Along with increasing product complexity and quality requirements, the consistent consideration of inevitable production-induced variations within the product development process becomes a decisive factor for the market success of products. Consequently, various tolerancing approaches have emerged over the last few decades. However, tolerancing is considered complex in education, research, and industry, as it is a highly interdisciplinary task that takes place at different levels of detail, ranging from Robust Design to tolerance specification to manufacturing process design. This contribution proposes a novel approach that allows a holistic and structured description of tolerancing and fosters a common understanding among all involved stakeholders from design, manufacturing, and inspection. This is achieved by categorizing it into several distinct elements: activities, methods, tools, models and data, information, and knowledge. This ensures clarity and supports the utilization of existing approaches. While this contribution focuses on tolerancing in product design, the linkage to subsequent product realization stages and further engineering domains is also addressed in the proposed description scheme. An exemplary classification of research papers and a description of a practical development process of a technical system with its different tolerancing activities illustrate the benefits of the proposed description schem
Keywords: Tolerancing; Dimensional Management; Variation Management; Robust Design; Product Design

Toleranz-Kosten-Optimierung abweichungsbehafteter Systeme - Wartzack, Sandro; Walter, Michael (Zeitschrift für wirtschaftlichen Fabrikbetrieb, 2014)
UnivIS-Import:2015-03-09:Pub.2014.tech.FT.FT-KLMEFK.tolera_1

Toleranz-Kosten-Optimierung bewegter Systeme mittels Partikelschwarm-Optimierung - Walter, Michael; Sprügel, Tobias; Weikert, Tim; Mann, Vincent; Romeis, Marcus; Wartzack, Sandro (Design for X. Beiträge zum 25. DfX-Symposium, 2014)
Both random and systematic deviations of manufactured parts as well as variation in manufacturing processes may have significant effects on the kinematic behavior of a mechanism. Hence, the product developer has to define both appropriate tolerances of the single parts and appropriate precision requirements of the manufacturing processes to ensure the mechanism’s functionality while causing low manufacturing costs. This paper presents an approach on the statistical tolerance-cost-optimization of a time-dependent system taking into account random and systematic deviations as well as the imprecision of corresponding manufacturing processes. The practical use of the approach is shown in a case study of a non-ideal cross-arm window regulator.
Keywords: tolerance optimization; mechanism; tolerance-cost-relations; particle swarm optimization

Toleranzmanagement 4.0: Chancen und Herausforderungen der zunehmenden Digitalisierung in der Fertigung für das Toleranzmanagement - Schleich, Benjamin; Wartzack, Sandro (Summer School Toleranzmanagement - Beiträge zur 3. Summer School - September 2017, 2017)

Toleranzmanagement am KTmfk - Wartzack, Sandro; Schleich, Benjamin; Walter, Michael; Ziegler, Philipp (Summer School Toleranzmanagement: Beiträge zur 1. Summer School, 2013)
UnivIS-Import:2015-04-16:Pub.2013.tech.FT.FT-KLMEFK.tolera_9

Toleranzmanagement am Lehrstuhl für Konstruktionstechnik - Wartzack, Sandro; Schleich, Benjamin; Heling, Björn; Aschenbrenner, Alexander; Götz, Stefan (Summer School Toleranzmanagement - Beiträge zur 3. Summer School - September 2017, 2017)

Toleranzmanagement im Kontext von Industrie 4.0 - Wartzack, Sandro; Schleich, Benjamin; Aschenbrenner, Alexander; Heling, Björn (Zeitschrift für wirtschaftlichen Fabrikbetrieb, 2017)
Das Toleranzmanagement umfasst alle Tätigkeiten zur Steuerung geometrischer Bauteilabweichungen entlang des Produktlebenszyklus und ist daher von großer Bedeutung für produzierende Unternehmen. Gewohnte Wertschöpfungsketten befinden sich jedoch angesichts der vierten industriellen Revolution im Umbruch. Der Beitrag gibt daher einen Überblick über die Chancen und Herausforderungen für das Toleranzmanagement im Kontext von Industrie 4.0 und stellt mögliche Lösungsansätze vor.

Toleranzmanagement in Konzept- und früher Entwurfsphase: Erste Ansätze und Potentiale - Götz, Stefan; Schleich, Benjamin; Wartzack, Sandro (Design for X. Beiträge zum 28. DfX-Symposium, 2017)
Accompanied by the frontloading efforts in product development, tolerancing becomes more and more important in early design stages. Motivated by the lack of methods for early phases of the design process, three approaches for considering tolerances in conceptual and preliminary design stages are presented in this paper. The first allows assessing the robustness of concepts with the help of a tolerance-specific FMEA. A subsequent method enables a tolerance specification and analysis based on a graphical visualization of the product structure. Furthermore, a sensitivity analysis for skeleton models is presented. By using these methods the design and tolerancing process runs simultaneously. Hence, a robust design and reliable tolerances already exist at the beginning of the detail design.
Keywords: Conceptual Design; Preliminary Design; Robust Design; Tolerance Analysis

Tolerierung bei der Auslegung endlosfaserverstärkter Faserverbundbauteile - Franz, Michael; Wartzack, Sandro (WiGeP News, 2021)

Topologieoptimierung mit transversal isotropem Materialmodell – Produktentwickler auf der Suche nach der optimalen Geometrie für Faser-Kunststoff-Verbunde - Völkl, Harald; Franz, Michael; Wartzack, Sandro (Design for X. Beiträge zum 28. DfX-Symposium, 2017)
Fiber-reinforced plastics bear a huge potential for lightweight design, especially due to their high strength-to-weight ratio and anisotropic behavior. Within topology optimization, due to the high number of dependent variables, specific solutions for transversely isotropic materials rarely exist – and existing ones require considerable computational effort. Yet, to fully exploit the lightweight potential, taking anisotropy into account is indispensable. A new bionic topology optimization approach is presented to facilitate efficient and effective optimization of such materials.
Keywords: Topology Optimization; FEA; Bionics; Fiber-reinforced plastic

Topology optimization of Compliant Mechanisms explicitly considering desired kinematics and stiffness constraints - Hasse, Alexander (Proceesdings of ASME 2016 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference IDETC2016, August 21-24, 2016, Charlotte, North Carolina, 2016)
A mechanism is designed to transform forces and/or displacements from an input to one or multiple outputs. This transformation is essentially ruled by the kinematics, i.e. the defined ratio between input and output displacements. Although the kinematics forms the basis for the design of conventional mechanisms, approaches for the topology and shape optimization of compliant mechanisms do not normally explicitly include the kinematics in their optimization formulation. The kinematics is more or less an outcome of the optimization process. A defined kinematics can only be realized by iteratively adjusting process-specific optimization parameters within the optimization formulation. Moreover, existing approaches normally minimize the strain energy that is stored in the compliant mechanisms according to a defined input and output displacement – although in some applications a certain amount of strain energy is required. This paper presents a new optimization formulation that solves the aforementioned problems. It is based on the principles of designing compliant mechanisms with selective compliance formerly presented by the author. The formulation is derived by means of an intensive workup of the design problem of compliant mechanisms. The method is validated for different design examples ranging from standard single-input/single-output mechanisms (force inverters) to multi-output mechanisms (shape-adaptive structures).
Keywords: Compliant mechanism; Topology optimization; Selective compliance

Toward cost-efficient tolerancing of 3D-printed parts: a novel methodology for the development of tolerance-cost models for fused layer modeling - Roth, Martin; Schächtl, Paul; Giesert, Andreas; Schleich, Benjamin; Wartzack, Sandro (International Journal of Advanced Manufacturing Technology, 2022)
Tolerance allocation methods significantly contribute to the qualification of Additive Manufacturing (AM) for (small-)series production ensuring high performance and efficiency. However, their usage prerequisites the availability of quantitative, reliable information on the impact of the assigned tolerances on the resulting manufacturing costs. The given article proposes a novel methodology for the systematic development of tolerance-cost curves for a cost-efficient tolerancing of 3D-printed parts. The proposed structured workflow aims at serving as a general guideline for both researchers and practitioners, while the exemplarily chosen perspective from Fused Layer Modeling (FLM) illustrates its adaption to a specific AM technology. The indirect, non-apparent interrelations between tolerances and resulting costs are modelled with the aid of an activity-based cost model, whereas the individual costs elements are mapped as function of the values for the machine-specific process parameters for AM, e.g., layer height or printing speed, which are required to achieve the assigned design tolerances. The total procedure covers all relevant steps, viz. the identification and quantification of the single cost items, the design of benchmark artifacts, adapted to given manufacturing and measuring techniques, the empirical determination of data on cost and geometrical accuracy by design of experiments and tolerance-cost curves. Its exemplary application to an academic use case shows its general applicability and benefits, but also its current limitations.
Keywords: Tolerance-cost function; Geometrical accuracy; Additive Manufacturing; Least cost tolerance allocation; Tolerance-cost optimization; Fused Layer Modeling

Towards a more comprehensive understanding of Tolerance Engineering research importance - Krogstie, Lars; Walter, Michael; Wartzack, Sandro; Martinsen, Kristian (Proceedings of the 13th CIRP Conference on Computer Aided Tolerancing, 2014)
UnivIS-Import:2015-04-16:Pub.2014.tech.FT.FT-KLMEFK.toward

Towards Biomechanical Digital Human Modeling of Elderly People for Simulations in Virtual Product Development - Miehling, Jörg; Geißler, Bastian; Wartzack, Sandro (Proceedings of the Human Factors and Ergonomics Society 2013 International Annual Meeting, 2013)
This contribution illustrates a methodology to customize biomechanical digital human models to resemble people of different age and ability groups for the use in simulations to support user-centered design. Especially the conception of man models of elderly people holds potential for analyzing and optimizing products to yield more universal designs, due to the high heterogeneity of needs, wants and capabilities in this specific age group. The present approach considers age-related performance restrictions, but is also extendable to disease-related limitations. The conception process itself includes the scaling of anthropometry, muscle forces, range of motion as well as motion speed based on data from literature or manual measurements. The parameters are either selected by percentiles or the specific values itself.
UnivIS-Import:2015-04-16:Pub.2013.tech.FT.FT-KLMEFK.toward

Towards CAD integrated simulation of use under ergonomic aspects - Krüger, Daniel; Wartzack, Sandro (Proceedings of the DESIGN 2014 13th International Design Conference, 2014)
In this paper biomechanical human models are proposed as a possibility to simulate ergonomic aspects of user-product interaction already in the early stages of the development process. Hereby designers are enabled to quantify the relationship between design parameters and the level of biomechanical stress prevalent during product use within the user.
Keywords: ergonomics; virtual product development; design for use

Towards Customized Digital Engineering: Herausforderungen und Potentiale bei der Anpassung von Digital Engineering Methoden für den Produktentwicklungsprozess - Gerschütz, Benjamin; Sauer, Christopher; Wallisch, Anne; Mehlstäubl, Jan; Kormann, Andreas; Schleich, Benjamin; Alber-Laukant, Bettina; Paetzold, Kristin; Rieg, Frank; Wartzack, Sandro (Stuttgarter Symposium für Produktentwicklung SSP 2021, 2021)
Mit dem Ziel, nationale und internationale Fachleute unterschiedlicher Disziplinen der Produktentwicklung aus Industrie und Wissenschaft in den Dialog zu bringen, organisiert der Verein zur Förderung produktionstechnischer Forschung e.V. und das Fraunhofer IAO gemeinsam mit dem Institut für Konstruktionstechnik und Technisches Design IKTD, dem Institut für Maschinenelemente IMA und dem Institut für Arbeitswissenschaft und Technologiemanagement IAT der Universität Stuttgart das Stuttgarter Symposium für Produktentwicklung SSP. Am 20. Mai 2021 findet das SSP zum sechsten Mal statt, diesmal als digitale wissenschaftliche Konferenz. Die Konferenz bietet Wissenschaftlern eine Plattform zur Präsentation und Diskussion ihrer neuesten Forschungsergebnisse im Bereich der Produktentwicklung und fördert so den interdisziplinären Wissenstransfer. Aufgerufen waren in der SSP 2021 Beiträge aus folgenden Kategorien: • Adaptive Bedienung für automatisiertes Fahren • Advanced Systems Engineering / Model-Based Systems Engineering • Agile Produktentwicklung • Design-Technik-Konvergenz • Digital Engineering • Innovations- und Technologiemanagement • Konstruktionsmethodiken • Leichtbau in der Produktentwicklung • Nachhaltige Produktentwicklung • Nutzerzentriertes Design • Wissensmanagement in der Produktentwicklung • Zuverlässige Produktentwicklung Im Plenum und vier Tracks mit jeweils drei Sessions werden 46 Beiträge präsentiert. Der Abstract der Keynote sowie die 45 Volltexte mit deutschen und englischen Abstracts sind in diesem Band zusammengefass
CRIS-Team Scopus Importer:2021-12-24
Keywords: Digital engineering; Industry 4.0; Product development

Towards individualized biomechanical models in multiple domains - Wechsler, Iris; Koelewijn, Anne; Wartzack, Sandro; Miehling, Jörg (28th Congress of the European Society of Biomechanics, 2023)

Towards Ontological Support for Principle Solutions in Mechanical Engineering - Breitsprecher, Thilo; Codesci, Mihai; Jucovaschi, Constantin; Kohlhase, Michael; Schröder, Lutz; Wartzack, Sandro (8th International Conference on Formal Ontology in Information Systems, 2014)
Among the standard stages of the engineering design process, the principle solution can be regarded as an analogue of the design specification, fixing the way the final product works. It is usually constructed as an abstract sketch where the functional parts of the product are identified, and geometric and topological constraints are formulated. Here, we outline a semantic approach where the principle solution is annotated with ontological assertions, thus making the intended requirements explicit and available for further machine processing; this includes the automated detection of design errors in the final CAD model, making additional use of a background ontology of engineering knowledg
UnivIS-Import:2015-04-16:Pub.2014.tech.FT.FT-KLMEFK.toward_5
Keywords: document-oriented processes; Knowledge-based engineering

Towards postural control simulation using a sensorimotor enhanced musculoskeletal human model - Shanbhag, Julian; Fleischmann, Sophie; Eskofier, Björn; Koelewijn, Anne; Wartzack, Sandro; Miehling, Jörg (ISPGR World Congress 2023, 2023)

Towards the Understanding of Lubrication Mechanisms in Total Knee Replacements – Part I: Experimental Investigations - Nečas, David; Vrbka, Martin; Marian, Max; Rothammer, Benedict; Tremmel, Stephan; Wartzack, Sandro; Galandáková, Adéla; Gallo, Jiří; Wimmer, Markus A; Křupka, Ivan; Hartl, Martin (Tribology International, 2021)
This contribution is aimed at the detailed understanding of lubrication mechanisms within total knee replacement. While Part I is focused on the experimental investigation, Part II deals with the development of a predictive numerical model. Here, a knee simulator was used for direct optical observation of the contacts between a metal femoral and a transparent polymer components. Transient dynamic conditions were applied. Mimicked synovial fluids with fluorescently labelled constituents were used as the test lubricants. The results showed that γ-globulin forms thin boundary lubricating film, being reinforced by the interaction of phospholipids and hyaluronic acid. Further development of lubricating film is attributed to albumin layering. Based on the results, a novel lubrication model of the knee implant is propose
Keywords: Total knee replacement; Knee simulator; Fluorescent microscopy; Lubrication; Experiment

Towards the Understanding of Lubrication Mechanisms in Total Knee Replacements – Part II: Numerical Modeling - Marian, Max; Orgeldinger, Christian; Rothammer, Benedict; Nečas, David; Vrbka, Martin; Křupka, Ivan; Hartl, Martin; Wimmer, Markus A; Tremmel, Stephan; Wartzack, Sandro (Tribology International, 2021)
Total knee replacements are an effective surgical treatment to restore the function of the knee. For an adequate design, knowledge about stresses and lubrication conditions is vital. Part II proposes a fully-coupled transient 3D model for the soft elastohydrodynamically lubricated contact based upon the generalized Reynolds equation and Finite Element Method while Part I of this study focused on experimental observations. Within the scope of this contribution, a numerical model is presented and validated with experimental data. Good agreement between model predictions and experimental data was found. A strong influence of fluid and geometry assumptions and transient effects were found. Besides, it was demonstrated that the rheological synovial fluid properties have a decisive role in the tribological behavio

Towards Virtual Assessment of Human Factors: A Concept for Data-Driven Prediction and Analysis of Physical User-product Interactions - Wolf, Alexander; Binder, Nicole; Miehling, Jörg; Wartzack, Sandro (Proceedings of the 22nd International Conference on Engineering Design (ICED19), 2019)
The early consideration of human factors in product development hugely favours the development of products, which excel with a positive user experience. The virtual environment of product development however, still has significant gaps in the virtual assessment and simulation of human factors, especially for user-product interactions composed of human movements. This motivates us to introduce a concept for data-driven prediction and analysis of user-product interactions. Heart of the concept is a predictive component that models the interaction between the user, represented by a musculoskeletal model, and the product, represented by product characteristics. We describe the implementation of this concept based on a pilot study for a lifting task. Motion capturing was performed to build a database and compare the results of our novel approach. The resulting kinematic and dynamic quantities show similar curve profiles with a small constant offset to the measured data. This indicates that the concept enables the virtual comparison of different designs or concepts regarding human factor
Keywords: User centred design; Simulation; Early design phases; User-product interaction; Data-driven movement prediction

Transfer des muskuloskelettalen Leichtbaus auf offene kinematische Ketten - Bartz, Marcel (Verlag Dr. Hut, 2019)
Viele Konstruktionsprinzipien des technischen Leichtbaus entstammen dem Muskel-Skelett-System des Menschen. Bisherige technische Umsetzungen vernachlässigen das abgestimmte Zusammenspiel der muskuloskelettalen Leichtbauprinzipien, da die Anwendung isoliert erfolgt. Im Rahmen dieser Arbeit wird das Leichtbaupotential des Zusammenspiels der Leichtbauprinzipien für die Technik untersucht. Für die Untersuchung wird ein bioinspiriertes Vorgehensmodell entwickelt, das die synchron stattfindenden biologischen Optimierungsstrategien in einem sequentiellen Ablauf für die Technik abbildet. Dies wird durch die Kopplung von Mehrkörpersimulation und Strukturoptimierung in einem iterativen Verfahren realisiert. Die Untersuchungen erfolgen an einfachen Balkensystemen und an einem technischen Gelenkarmroboter. Die Ergebnisse zeigen, dass durch das neue Verfahren die Masse und Verformungsenergie im Vergleich zu einer klassischen technischen Auslegung reduziert werden können.

tribAIn – An ontology for knowledge representation in the domain of tribology - Kügler, Patricia; Marian, Max; Schleich, Benjamin; Tremmel, Stephan; Wartzack, Sandro (60. Tribologie-Fachtagung 2019. Reibung, Schmierung und Verschleiß. Forschung und praktische Anwendungen, 2020)
The tribAIn ontology aims to formalize knowledge obtained from tribological experiments, for supporting knowledge access and reuse. Due to the isolated and heterogeneous data sources, knowledge management with semantic technologies provide tremendous opportunities over classical databases. Especially the focus on meaning of data instead of the structure of data is suited for knowledge-intensive domains, like tribology. This meaning is formally and explicitly represented by the tribAIn ontology, which provides concepts and definitions for annotating and linking data gained from different sources, like measurement series as tabular data or results interpretation in natural language. From the perspective of an ontology-based application the tribAIn ontology forms the global scheme for querying and accessing the underlying data sources, which are linked by mapping schemes to the ontology. Compared to data warehousing, this makes semantic approaches much more flexible with respect to updating and extension of knowledge bases.<br
Keywords: ontology; tribological testing; knowledge reuse; semantic integration

tribAIn - Towards an Explicit Specification of Shared Tribological Understanding - Kügler, Patricia; Marian, Max; Schleich, Benjamin; Tremmel, Stephan; Wartzack, Sandro (Applied Sciences, 2020)
Within the domain of tribology, the science and technology for understanding and controlling friction, lubrication, and wear of relatively moving interacting surfaces, countless experiments are carried out and their results are published worldwide. Due to the variety of test procedures and a lack of consistency in the terminology as well as the practice of publishing results in the natural language, accessing and reusing tribological knowledge is time-consuming and experiments are hardly comparable. However, for the selection of potential tribological pairings according to given requirements and to enable comparative evaluations of the behavior of different tribological systems or testing conditions, a shared understanding is essential. Therefore, we present a novel ontology tribAIn (derived from the ancient Greek word “tribein” (= rubbing) and the acronym “AI” (= artificial intelligence)), designed to provide a formal and explicit specification of knowledge in the domain of tribology to enable semantic annotation and the search of experimental setups and results. For generalization, tribAIn is linked to the intermediate-level ontology EXPO (ontology of scientific experiments), supplemented with subject-specific concepts meeting the needs of the domain of tribology. The formalization of tribAIn is expressed in the W3C standard OWL DL. Demonstrating the ability of tribAIn covering tribological experience from experiments, it is applied to a use case with heterogeneous data sources containing natural language texts and tabular dat
Keywords: ontology; tribology; tribological testing; formalization; knowledge reuse; knowledge representation

Tribocatalytic Mo-X-N Coating System for Higher Efficiency of Engine Components - Dobrenizki, Ladislaus; Brugnara, Ricardo; Tremmel, Stephan; Wartzack, Sandro (MTZ Motortechnische Zeitschrift, 2020)
Surface coating is one of the most effective measures for reducing friction losses in combustion engines. High potential exists, for example, in the tribological contact between the tappet and the camshaft in the valve train. In this article, Schaeffler presents a nanostructured tribocatalytic PVD coating system made of molybdenum that forms protective tribofilms on the stressed surface. <br
Keywords: PVD Coatings; Friction reduction; Combustion Engine

Tribological adjustment of tungsten-modified hydrogenated amorphous carbon coatings by adaption of the deposition parameters - Hetzner, Harald; Zhao, Rong; Tremmel, Stephan; Wartzack, Sandro (Proceedings - 10th International Conference THE "A" Coatings, 2013)
In comparison to pure hydrogenated amorphous carbon coatings (a-C:H), the metal-modified variants (a-C:H:Me) are known to have better adhesion to the substrate due to lower residual stresses and brittleness. For this reason, particularly in higher loaded applications, like metal forming tools, a-C:H:Me is usually preferred over a-C:H, even though hardness and hence abrasion protection tends to be lower. Another interesting feature of a-C:H:Me is that, depending on the deposition parameters, the coating properties can be varied over wide ranges: From carbide-like to amorphous-carbon-like. In the present study, tungsten-modified hydrogenated amorphous carbon coatings (a-C:H:W) were deposited on tool steel by reactive magnetron sputtering of a tungsten-carbide target in argon-ethine atmosphere. From batch to batch, the four most relevant deposition parameters were varied according to a factorial design. The coatings were characterised in terms of their structural, mechanical and tribological properties. Using a statistics software, the deposition parameters significantly influencing the respective properties could be identified.
Keywords: reactive sputtering; amorphous carbon; tailored friction; factorial design

Tribological aspects in manufacturing processes of microstructured components and their tribological behavior in operation - Schrader, Tobias; Weschta, Martin; Merklein, Marion; Tremmel, Stephan; Engel, Ulf; Wartzack, Sandro (Proc. 6th International Conference on Tribology in Manufacturing Processes and Joining by Plastic Deformation, 2014)
An ever increasing mobility and a shortage of resources lead to restrictive politically driven limits for fuel consumption as well as an increasing demand of customers for efficient vehicles. Though electrification of cars proceeds, combustion engines will play an important role for conventional and hybrid concepts within next decades. Thus, for a contribution to increasing energy efficiency of vehicles it is vital to trace sources of friction losses and to identify possibilities for friction reduction in combustion engines. Therefore, the follower as a main contributor to friction losses in valve trains was chosen as a demonstrator for friction reduction effects by microstructured components. However, the realization of theoretically advantageous microstructures with filigree geometries is challenging for manufacturing technologies. The present study focuses on the elaboration of a technological basis for a repeatable production of components with microstructured surfaces by a combined cup backward extrusion micro coining process, coping with the demands of large-lot production. For realization of a high accuracy the influence of friction on geometry of microstructured components was investigated. In addition, running-in of components is decisive for final geometry and tribological behavior of microstructured surfaces and hence considered as well.
Keywords: Accuracy; Microstructures; Tribology

Tribological behavior of amorphous carbon coatings on Ti6Al4V alloy and UHMWPE for total knee replacement using a pin-on-disk tribometer - Rothammer, Benedict; Bartz, Marcel; Wartzack, Sandro (DKOU 2022, 2022)
Objectives: The aim of the endoprosthetic replacement of joints is to restore functionality and to provide patients with a painless life. Total knee replacements (TKR) usually consist of a Co28Cr6Mo (CoCr) femoral component that rubs against UHMWPE (PE) inlay. The wear particles removed from TKR are largely responsible for early prosthetic failure, primarily due to aseptic loosening. This study focused on the characterization and tribological testing of wear-reducing amorphous carbon coatings with good adhesion to Ti6Al4V (Ti64) and PE and to analyze wear mechanisms and influencing factors. Methods: Due to promising tribologically effective behavior, a tungsten-doped hydrogen-containing amorphous carbon coating (a-C:H:W) was applied to the Ti64 (Ti64:W) pins and an a-C:H coating to the UHMWPE (PE:H) disks by physical vapor deposition (PVD). A thin adhesive layer of titanium and an intermediate layer of tungsten carbide were used to achieve a good coating-substrate adhesion. In contrast, the a-C:H coating was applied to the PE substrate by reactive PVD without intermediate layers. The coating samples were characterized regarding coating thickness and adhesion to substrate using crater-grinding method [1] and scratch testing [2], respectively. Hardness was measured by instrumented indentation test [3]. The tribological behavior of the coated material pairings in comparison to the uncoated pairings was investigated utilizing a climate-controlled pin-on-disk tribometer. Efforts were made to reproduce the boundary conditions in the peri-implant environment, whereby the diluted bovine serum used was tempered to 37°C in fully flooded lubrication. The wear rates were determined using light and laser scanning microscopy. Results and conclusion: With an indentation hardness of about 16GPa, a-C:H:W coating (thickness of < 1 µm) was significantly harder than CoCr or Ti64 The coating systems deposited on Ti64 endured loads of about 8N in scratch tests without spalling. The a-C:H coating had a thickness of about 1.5µm and an indentation hardness of about 1.5GPa, which represented a forty-fold increase compared to substrate hardness while maintaining high adhesion. Thus, no coating applied to PE showed any damage in the form of chipping in the scratch tests. The wear rates of uncoated and coated disks as well as uncoated and coated pins are compared in figure 1. It was found that a coated sliding combination reduces wear on PE disks by about 41% and on pins by 77%. The a-C:H coating was suitable for preventing wear on PE due to its inert character and its favorable HIT/EIT ratio. A similar behavior was observed for the a-C:H:W coated Ti64 pins compared to the uncoated Ti64 and CoCr pins. Despite the pin having permanently been in contact, the magnitude of the wear rate differed between PE and metal substrates by a factor of 10. This could be attributed to the stiffer and harder character of metals, which could be supplemented by an additional coating with a-C:H:W to achieve tribologically favorable behavior. References German Institute for Standardization (DIN). DIN EN ISO 26423. 2016. German Institute for Standardization (DIN). DIN EN ISO 20502. 2016. German Institute for Standardization (DIN). DIN EN ISO 14577-1. 2015.

Tribological Behavior of Carbon Based Coatings Adapted to Lubricant-Free Forming Conditions - Tenner, Jennifer; Zhao, Rong; Tremmel, Stephan; Häfner, Tom; Schmidt, Michael; Merklein, Marion (International Journal of Precision Engineering and Manufacturing - Green Technology, 2018)
In conventional deep drawing lubricants are applied to achieve low friction and wear. However, most lubricants contain environmental harmful ingredients. Global trends like sustainability and efficient resource usage motivate the development of lubricant-free deep drawing. However, dry contact conditions lead to intensive interaction between tool and workpiece especially for aluminum alloys with high adhesion tendency towards tool steel. First investigations revealed promising results for diamond like carbon (DLC) coated tools in lubricant-free tests. Therefore, in this study the lubricant-free friction and wear behavior of DLC coatings is investigated in strip drawing tests. To ensure industrial-like conditions commonly used deep drawing steel with zinc coating and an aluminum alloy were selected as sheet material. The properties of DLC coatings were modified at different scales to attain tailored tribological conditions. A laser based heat treatment achieved an increase of sp2 hybridization and thus leads to increased friction. Different mechanical pre- and post-treatment strategies like polishing and brushing proved that a smooth tool surface is beneficial for the tribological conditions in dry contacts. With laser generated structures a modification of friction was realized with varying degree of coverage for DC04. In contact with AA5182 the application of structures is limited due to adhesion.
CRIS-Team Scopus Importer:2022-06-05
Keywords: Carbon based coatings; Dry deep drawing; Surface modification; Tribology

Tribological behavior of ceramic disks for application in mixer taps under different lubrication conditions - Ziegler, Marlene; Rothammer, Benedict; Marian, Max; Henzler, Stephan; Beau, Patrick; Bartz, Marcel; Wartzack, Sandro (5th YOUNG TRIBOLOGICAL RESEARCHER SYMPOSIUM, 2022)
There are many tribological systems where technical ceramics are used because of their hardness and high wear resistance. Even in a mixer tap two ceramic disks are integrated in the cartridge. A common problem is the change of the haptic properties during usage, because of changes in the tribological system. Within this work the possibility of reproducing effects relvant for application in model tests is studied. Therefore, a ball-disk-tribometer in oscillating sliding mode was used to test ceramic-ceramic-pairings with varying lubricants. The tests ran without lubricant and with three lubricants of different qualities. Through the addition of any of the lubricants a reduction of the coefficient of friction in comparison to the test runs without lubricant was monitored. To consult the influence of higher temperature due to hot water inflow, all tests were performed at room temperature and at 65 °C. This variation of parameter had no big influence on the test results of tests without lubricant. In the tests with lubricants the coefficient of friction showed a clear dependency on change of temperature. To make a statement with respect to the original system, three mixer taps with different haptically characteristics were used as references

Tribological behavior of coated tungsten composites in sliding contact conditions with steel counter bodies - Sander, Thomas; Tremmel, Stephan; Wartzack, Sandro (Proceedings of the 15th Nordic Symposium on Tribology NORDTRIB 2012, 2012)
UnivIS-Import:2015-04-16:Pub.2012.tech.FT.FT-KLMEFK.tribol

Tribological Behavior of Diamond-Like Carbon (DLC) Coatings on Metals for Total Knee Arthroplasty Under Boundary Friction Conditions - Rothammer, Benedict; Weikert, Tim; Tremmel, Stephan (International Tribology Conference Sendai 2019, 2019)
The knee joint is one of the most stressed joints in the human body. The failure of a natural knee joint is 96 % due to gonarthrosis, which requires the implantation of an artificial joint. However, a primary artificial knee joint has an average lifetime of about 15 years. Wear is the most common reason for load-bearing implant failure, as this leads to an aseptic loosening of the knee arthroplasty. In implant research, efforts are being made to reduce polymeric inlay wear by the application of tribologically effective Diamond-like Carbon (DLC) coatings. Therefore, this study focuses on the deposition of wear-reducing coating systems with high adhesion to the medical substrates Ti6Al4V (3.7165; 39 ± 2 HRC) and CoNi35Cr20Mo10 (2.4999; 47 ± 1 HRC). For this reason, pure (a‑C:H), silicon oxide-modified (a‑C:H:SiO) and titanium-containing (a‑C:H:Ti) hydrogen-containing amorphous carbon coatings are investigated with regard to the forms of wear. Subsequently, wear mechanisms have to be identified in order to derive wear-reducing coating systems. The tribological effectiveness of the carbon coating systems can be promoted in particular by a high adhesion to the base material, so that further attention is paid to the mechanical investigation of the adhesion. The uncoated and coated samples were tested against medical PE‑UHMW (1401; HB = 33 N/mm2) in a ring-on-disc test with minimal lubrication of fetal bovine serum (FBS). Various wear mechanisms were observed during the sliding process, which in turn affect the coefficient of friction. The obvious traces of wear on PE‑UHMW indicate abrasive and adhesive wear. The wear particles are usually fibrous or particulate and have a size of at least 33.8 µm. This value is above the critical value of 0.1 µm, below which increased macrocytic reactions are triggered even with small abrasion volume, and thus promote the risk of osteolysis and also of aseptic loosening. A reason for the discrepancy in particle size arises from the different in‑vitro test setups (tribometer, knee simulator) and the in‑vivo used joint replacement. In general, the wear volume should be kept low for particles in the order of 0.2...0.6 µ
Keywords: Tribology; Diamond-like Carbon (DLC) Coatings; PE-UHMW Wear; Total Knee Arthroplasty

Tribological behavior of different doped ta-C coatings for slip-rolling contacts with high hertzian contact pressure - Polzer, Markus; Bartz, Marcel; Rothammer, Benedict; Schulz, Edgar; Wartzack, Sandro (Industrial Lubrication and Tribology, 2023)
Purpose The curved and tribologically highly stressed surfaces of bearing components pose a major challenge for steel alloys or tribological resistant coatings like tetrahedral amorphous carbon (ta-C) coatings which in particular have an increased risk of delamination due to the significantly increased residual stresses. A possibility to prevent coating failure is the use of dopants while maintaining or even increasing tribological properties. This study aims to compare the tribological behavior of several doped diamond-like-carbon coatings with an undoped ta-C coating under varying slip conditions and Hertzian pressure up to 1800 MPa. Design/methodology/approach For this purpose, the tribological behavior was studied using of a ball-on-disc tribometer and a two-disc test rig under mixed/boundary conditions. The tests were conducted with coated specimens against uncoated 100Cr6 steel. Additionally, the influence of lubrication additives was studied due to the use of two fully formulated PAO-based oils, one without and one with molybdenum containing additives. The friction was measured in situ, and the wear was analyzed trough laser scanning microscopy and tactile measurement. Findings It was shown that the use of doped ta-C coatings exhibited a tendency for a more favorable tribological behavior compared to undoped ta-C coatings, with no general dependence on the lubricants used. The use of the most suitable coatings reduced the wear of the steel counter-body considerably. Originality/value To the best of the authors’ knowledge, this is the first approach of testing the tribological behavior of these doped ta-C coatings, developed for friction efficiency, in dependency on lubrication additives under the given load collective. The approach is relevant to determine whether the friction reduction and the wear inhibition of these coatings are suitable for higher contact pressures and load cycles.<br
Keywords: Tribology; DLC; ta-C coating; Friction; Wear; Slip-rolling; 2-Disc-tribometer

Tribological behaviour of amorphous carbon coatings for total knee arthroplasty - Rothammer, Benedict; Neusser, Kevin; Tremmel, Stephan; Bartz, Marcel; Wartzack, Sandro (5th International Conference on BioTribology, 2021)
Endoprosthetic replacement of the joint intends to restore the functionality and to provide the patient with a pain-free and more mobile life. However, aseptic loosening of the total knee arthroplasty (TKA) is a major cause of early prosthesis failure and is multifactorial in etiology with wear debris removed from the implant materials being largely responsible. For this reason, a great effort is made to reduce polymeric inlay wear by applying tribologically effective surface modifications. Thus, this study concentrated on the deposition of wear-reducing amorphous carbon coating systems with good adhesion to the materials Co28Cr6Mo and PE-UHMW used for medical technology applications by means of physical vapour deposition (PVD) and plasma-enhanced chemical vapour deposition (PECVD). The tribological effectiveness of the carbon coating systems can be particularly be enhanced by a good adhesion to the substrate. Therefore, specific attention was also paid to the investigation of adhesion. The tribological behaviour of the coated material pairings in comparison to the uncoated pairings was investigated utilizing a clima-controlled pin-on-disc tribometer in rotational sliding mode. The tribological behaviour was studied under mixed friction conditions for a total number of 200 000 sliding cycles. A bovine serum, tempered to 37 °C, was used as a substitute synovial fluid. The wear rates were determined using light and laser scanning microscopy every 20 000 cycles. Thereby, various wear mechanisms were detected, which in turn affected the coefficient of friction. The strong wear traces on PE-UHMW indicated abrasive and adhesive wear. Consequently, the present study showed the applicability of well-adhering coatings to the considered materials used for applications in medical technology and the potential for wear reduction. Furthermore, the tribometric characteristics obtained serve as a basis for further development of the coating systems.
Keywords: Tribology; Amorphous carbon coatings; Wear; Total knee arthroplasty

Tribological behaviour of MoS2 in hydrogen environment - Schneider, Thomas; Gradt, Thomas; Vierneusel, Bernd; Tremmel, Stephan; Wartzack, Sandro (Proceedings of the 5th World Tribology Congress WTC 2013, 2014)
UnivIS-Import:2015-04-16:Pub.2013.tech.FT.FT-KLMEFK.tribol_7

Tribological Behaviour of PVD-Coated Dry-Running Rolling Bearings - Kröner, Julia; Kursawe, Serge; Musayev, Yashar; Tremmel, Stephan (Proceedings of The 18th Nordic Symposium on Tribology – NORDTRIB 2018, 2018)
Rolling bearings which are used under extreme conditions or restrictions may not be conventionally lubricated. Important lubricant requirements, such as friction reduction and wear protection, can no longer be ensured and premature failure of the bearing occurs. Within the scope of this research, coated components are used to undertake these two important tasks. The investigated coating systems are applied as PVD coatings (physical vapour deposition) on the rolling elements. The counter body in the rolling contact is either made of ceramic (silicon nitride - Si3N4), steel (100Cr6) or coated as well. The coated rolling bearings are deep grooved ball bearings, which are operated under realistic conditions on a friction test rig and are tested for lifetime. Afterwards, the friction and wear behaviour is analysed with the aid of the measured friction torque trends and various microscopic analyses. Promising results showed, in particular, a modified hydrogenated amorphous carbon coating system with a metallic doping element (a-C:H:Me) functional layer. Depending on the material combination of rings and balls and on which bearing element the coating was applied, a predefined minimum requirement for lifetime, low friction or very damage tolerant behaviour could be achieved.<br
Keywords: Rolling bearing; dry running; PVD coating; amorphous carbon coating system; component test

Tribological behaviour of tungsten doped hydrogenated amorphous carbon coatings deposited under various bias voltages and argon flows - Zhao, Rong; Weikert, Tim; Tremmel, Stephan; Wartzack, Sandro (Proceeding 11th Coatings Science International COSI 2015, 2015)
In this paper, variants of tungsten doped hydrogenated amorphous carbon coatings (a-C:H:W) were deposited on high speed steel by reactive magnetron sputtering. During the deposition process the bias voltage and argon flow were varied according to a 3x3 grid line experimental design. The coatings were investigated in terms of their topological, mechanical and tribological properties with different interfacial mediums. Raman spectroscopy was used to identify phase composition of the coatings.

Tribological comparison of different doped DLC coatings under rolling-sliding conditions - Polzer, Markus; Bartz, Marcel; Wartzack, Sandro (5th YOUNG TRIBOLOGICAL RESEARCHER SYMPOSIUM, 2022)

Tribological measures for controlling material flow in sheet-bulk metal forming - Löffler, Maria; Andreas, Kolja; Engel, Ulf; Schulte, Robert Karl; Gröbel, Daniel; Krebs, Eugen; Freiburg, Dennis; Biermann, Dirk; Stangier, Dominic; Tillmann, Wolfgang; Weikert, Tim; Wartzack, Sandro; et al. (Production Engineering, 2016)
Sheet-bulk metal forming (SBMF) is characterized by successive and/or simultaneous occurrence of quite different load conditions regarding stress and strain states. These conditions significantly influence the material flow and thus the geometrical accuracy of the components. To improve the product quality a control of the material flow is required. An appropriate approach is given by locally adapted tribological conditions due to surface modifications of tool and workpiece, so-called tailored surfaces. Within the present study different methods to adapt the surfaces are presented and investigated with respect to their tribological effectiveness in SBMF. In a first step, requirements regarding necessary adaptions of the friction values for two SBMF processes are numerically defined. Based on the requirements different tailored surfaces are presented and analyzed regarding their tribological influence. Finally, the potential of surface modifications to improve SBMF processes is shown.
Keywords: Tribology; Surface modification; Sheet-bulk metal forming

Tribological studies on multi-coated forming tools - Weikert, Tim; Tremmel, Stephan; Stangier, Dominic; Tillmann, Wolfgang; Krebs, Eugen; Biermann, Dirk (Journal of Manufacturing Processes, 2020)
Processes of Sheet-Bulk Metal Forming combine operations of both sheet and bulk metal forming, enabling the production of closely-toleranced functional components. Locally differing friction conditions on a single tool surface are crucial to control the material flow and to reduce process forces and tool wear. In order to understand how different friction conditions on a multi-coated tool surface affect the material flow during forming operations, variants of amorphous carbon coatings (a-C:H:W) and Cr-based hard coatings (CrAlN, CrAlCN) were deposited in combinations side by side on punches of ring compression tests. Evaluating the rings’ shapes revealed the coatings’ effects on material flow in terms of ring inner contours with sections of varying curvatures. Characteristic friction mechanisms were observed, which allowed a local delimitation of friction conditions by selectively applied coating
Keywords: Sheet-bulk metal forming; Tailored surfaces; Cr-based hard coatings; Amorphous carbon coatings

Tribologie in der Endoprothetik; Reibung und Verschleiß, ein Schlüssel zu langen Standzeiten - Döring, Joachim; Bormann, Therese; Buchholz, Adrian; Rothammer, Benedict; Hembus, Jessica; Uhler, Maximilian (Der Orthopäde, 2024)
Dieser Themenbeitrag soll eine der Schlüsselrollen im Hinblick auf die endoprothetische Versorgung mit künstlichen Implantaten und der Verlängerung der Standzeiten aufzeigen. Wie jedes Gelenk unterliegen gerade auch künstliche Gelenke den physikalischen Gesetzten von Reibung und Verschleiß – kurz der Tribologie. Dabei spielen besonders Materialpaarungen, Oberflächen und Wirkmechanismen eine entscheidende Rolle. Auf die Besonderheiten und aktuelle Erkenntnisse in Bezug auf die drei größten Synovialgelenke (Hüfte, Knie und Schulter) soll im Einzelnen eingegangen und Anregungen für zukünftige Entwicklungen gegeben werden. Mit stetigen Weiterentwicklungen im Bereich der Tribologie von künstlichen Gelenken kann die Versorgung für den Patienten massiv verbessert werden. Die Revisionszahlen und -gründe zeigen schon jetzt den Erfolg einzelner Verbesserungen der letzten Jahre.<br
Keywords: Korrosion; Endoprothesen; Hüfte; Materialwissenschaft; Schulter

Tribologische Dünnschichten für die Blechmassivumformung - Hetzner, Harald; Tillmann, Wolfgang; Tremmel, Stephan; Herper, Jan (Tagungsband zum 1. Workshop Blechmassivumformung 2011, 2011)
UnivIS-Import:2015-04-16:Pub.2011.tech.FT.FT-KLMEFK.tribol_2

Tribologisches Einsatzverhalten von diamantähnlichen Kohlenstoff-schichten (DLC) auf Werkzeugstahl gegenüber Stahl- und Alumini-umblechwerkstoffen für Trockentiefziehprozesse - Zhao, Rong; Tremmel, Stephan (Tribologie und Schmierungstechnik, 2016)
Aufgrund des wachsenden Umweltbewusstseins und begrenzter Erdölressourcen wird eine Reduzierung von oder sogar der komplette Verzicht auf Schmieröl bei Umformprozessen angestrebt. Dadurch wird der kostenintensive und teils umweltschädliche Arbeitsschritt zur Entfernung des auf dem Blech verbleibenden Schmieröls eingespart. Im Rahmen dieses Beitrags werden wolframmodifizierte wasserstoffhaltige amorphe Kohlenstoffschichten (a‑C:H:W) und tetraedrische wasserstofffreie amorphe Kohlenstoffschichten (ta‑C) als zwei potenzielle Kandidaten für die Beschichtung von Tiefziehwerkzeugen für die Trockenumformung untersucht. Hauptziel ist es, adhäsiven Materialübertrag, insbesondere bei Aluminiumlegierungen, auf die Werkzeugoberfläche zu minimieren. Hierzu wurden a‑C:H:W‑ und ta‑C‑Dünnschichten auf gehärteten Werkzeugstahloberflächen (1.2379, 60 HRC) abgeschieden. Anschließend wurden die Schichten hinsichtlich ihrer Schichtdicke, mechanischen Eigenschaften sowie Oberflächentopographie charakterisiert. Das Verschleißverhalten im trockenen Gleitkontakt gegenüber den Blechwerkstoffen DC04 (verzinkt), AA6014 wurde mittels eines Ring-Scheibe-Tribometers geprüft. Während des Laufs wurden unterschiedliche dominierende Verschleißmechanismen beobachtet, die wiederum die Reibungszahlen stark beeinflussen. Eine wesentliche Einflussgröße stellt die Oberflächenrauheit der Werkzeugoberflächen nach dem Beschichtungsprozess und im Weiteren die Verhakung der Rauheitsspitzen im weichen Blechmaterial (Zink, Aluminium) da
Keywords: Diamantähnlicher amorpher Kohlenstoff; Trockenumformen; Ring-Scheibe-Versuch

Tribologisches Einsatzverhalten von diamantähnlichen Kohlenstoffschichten (DLC) auf Werkzeugstahl gegenüber Stahl- und Aluminiumblechwerkstoffen für Trockentiefziehprozesse. - Zhao, Rong; Tremmel, Stephan (56. Tribologie-Fachtagung, 2015)
Aufgrund des wachsenden Umweltbewusstseins und begrenzter Erdölressourcen wird eine Reduzierung von oder sogar der komplette Verzicht auf Schmieröl bei Umformprozessen angestrebt. Dadurch wird der kostenintensive und teils umweltschädliche Arbeitsschritt zur Entfernung des auf dem Blech verbleibenden Schmieröls eingespart. Im Rahmen dieses Beitrags werden wolframmodifizierte wasserstoffhaltige amorphe Kohlenstoffschichten (a‑C:H:W) und tetraedrische wasserstofffreie amorphe Kohlenstoffschichten (ta‑C) als zwei potenzielle Kandidaten für die Beschichtung von Tiefziehwerkzeugen für die Trockenumformung untersucht. Hauptziel ist es, adhäsiven Materialübertrag, insbesondere bei Aluminiumlegierungen, auf die Werkzeugoberfläche zu minimieren. Hierzu wurden a‑C:H:W‑ und ta‑C‑Dünnschichten auf gehärteten Werkzeugstahloberflächen (1.2379, 60 HRC) abgeschieden. Anschließend wurden die Schichten hinsichtlich ihrer Schichtdicke, mechanischen Eigenschaften sowie Oberflächentopographie charakterisiert. Das Verschleißverhalten im trockenen Gleitkontakt gegenüber den Blechwerkstoffen DC04 (verzinkt), AA6014 und AA5182 wurde mittels eines Ring-Scheibe-Tribometers geprüft. Während des Laufs wurden unterschiedliche dominierende Verschleißmechanismen beobachtet, die wiederum die Reibungszahlen stark beeinflussen. Eine wesentliche Einflussgröße stellt die Oberflächenrauheit der Werkzeugoberflächen nach dem Beschichtungsprozess und im Weiteren die Verhakung der Rauheitsspitzen im weichen Blechmaterial (Zink, Aluminium) dar.
Keywords: Diamantähnlicher amorpher Kohlenstoff; Trockenumformen; Ring-Scheibe-Versuch

Tribologisches Verhalten amorpher Kohlenstoffschichten auf Metallen für die Implantologie im Zustand der Grenzreibung - Rothammer, Benedict; Weikert, Tim; Tremmel, Stephan; Wartzack, Sandro (59. Tribologie-Fachtagung. Reibung, Schmierung und Verschleiß. Forschung und praktische Anwendungen. Band 2, 2018)
Der häufigste Grund für einen Implantatausfall stellt Verschleiß dar, da dieser vor allem zu einer aseptischen Lockerung des Implantats führt. Deshalb sollen in dieser Studie die polymeren Verschleißpartikel des Inlays durch den Einsatz tribologisch wirksamer Kohlenstoffschichten (DLC, diamond-like carbon) auf Implantatoberflächen reduziert und dadurch der Abrasivverschleiß minimiert werden. Daher wurden amorphe Kohlenstoffschichten auf Ti6Al4V (3.7165; 39 ± 2 HRC) und CoNi35Cr20Mo10 (2.4999; 47 ± 1 HRC) abgeschieden. Bei den abgeschiedenen Schichten handelt es sich um je eine reine (a-C:H), siliziumoxid- (a-C:H:SiO) und titandotierte (a-C:H:Ti) wasserstoffhaltige amorphe Kohlenstoffschicht. Der Fokus dieses Beitrags liegt auf einem Screening der Schichten bezüglich der Verschleißerscheinungsformen. Darauf aufbauend sollen mittelfristig wirkende Verschleißmechanismen identifiziert werden, um anschließend verschleißreduzierende Schichtsysteme ableiten zu können. Die tribologische Wirksamkeit der Kohlenstoffschichtsysteme lässt sich insbesondere durch eine hohe Haftung auf dem Grundwerkstoff begünstigen, sodass ein weiteres Augenmerk auf der mechanischen Untersuchung der Schichthaftung liegt. Die un- und beschichteten Proben wurden gegenüber medizinischem PE-UHMW (1401; HB = 33 N/mm2) in einem Ring-Scheibe-Versuch getestet. Als Schmierstoff kam fetales Rinderserum (FBS) zum Einsatz. In den Versuchen wurden unterschiedliche dominierende Verschleißmechanismen beobachtet, die wiederum die Reibungszahlen stark beeinflussen. Die deutlich sichtbaren Verschleißspuren auf dem PE-UHMW deuten auf Abrasiv- und Adhäsivverschleiß hin. Die Verschleißpartikel sind meist faser- oder partikelförmig ausgeprägt und liegen mit einer Größe von mindestens 33,8 µm deutlich über dem von BANKSTON et al. für kritisch befunden Wert von 0,1 µm, ab welchem das Osteolysenrisiko durch erhöhte makrozytäre Reaktionen begünstigt wird.
Keywords: Diamantähnlicher amorpher Kohlenstoff (DLC); Implantologie; Ring-Scheibe-Versuch

Tribologisches Verhalten amorpher Kohlenstoffschichten auf Metallen für die Knie-Totalendoprothetik - Rothammer, Benedict; Weikert, Tim; Tremmel, Stephan; Wartzack, Sandro (Tribologie und Schmierungstechnik, 2019)
Der häufigste Grund für einen Implantatausfall stellt Verschleiß dar, da dieser vor allem zu einer aseptischen Lockerung des Implantats führt. Deshalb sollen in dieser Studie die polymeren Verschleißpartikel des Inlays durch den Einsatz tribologisch wirksamer Kohlenstoffschichten (DLC, diamond-like carbon) auf Implantatoberflächen reduziert und dadurch der Abrasivverschleiß minimiert werden. Daher wurden amorphe Kohlenstoffschichten auf Ti6Al4V (3.7165; 39 ± 2 HRC) und CoNi35Cr20Mo10 (2.4999; 47 ± 1 HRC) abgeschieden. Bei den abgeschiedenen Schichten handelt es sich um je eine reine (a-C:H), siliziumoxid- (a-C:H:SiO) und titandotierte (a-C:H:Ti) wasserstoffhaltige amorphe Kohlenstoffschicht. Der Fokus dieses Beitrags liegt auf einem Screening der Schichten bezüglich der Verschleißerscheinungsformen. Darauf aufbauend sollen mittelfristig wirkende Verschleißmechanismen identifiziert werden, um anschließend verschleißreduzierende Schichtsysteme ableiten zu können. Die tribologische Wirksamkeit der Kohlenstoffschichtsysteme lässt sich insbesondere durch eine hohe Haftung auf dem Grundwerkstoff begünstigen, sodass ein weiteres Augenmerk auf der mechanischen Untersuchung der Schichthaftung liegt. Die un- und beschichteten Proben wurden gegenüber medizinischem Polyethylen-Ultra High Molecular Weight (PE-UHMW, 1401; HB = 33 N/mm2) in einem Ring Scheibe-Versuch getestet. Als Schmierstoff kam fetales Rinderserum (FBS) zum Einsatz. Die Verschleißpartikel sind in der Regel faser- oder partikelförmig ausgeprägt und weisen mindestens eine Größe von 33,8 μm auf. Dieser Wert ist oberhalb des kritischen Werts von 0,1 μm, unterhalb dessen bereits bei kleinem Abriebvolumen erhöhte makrozytäre Reaktionen ausgelöst werden. Dadurch wird das Risiko einer Osteolyse und ferner einer aseptischen Lockerung begünstigt. Ein Grund für die Abweichung der Partikelgrößen liegt in den unterschiedlichen in-vitro Versuchsaufbauten (Tribometer, Kniesimulator) und dem in-vivo eingesetzten Gelenkersatzes begründet. Generell sollte das Verschleißvolumen für Partikel in einer Größenordnung von 0,2…0,6 μm gering gehalten werden.
Keywords: Diamantähnlicher amorpher Kohlenstoff (DLC); Knie-Totalendoprothese; Ring-Scheibe-Versuch; Verschleiß

Tribologische Wechselwirkungen zwischen amorphen Kohlenstoffschichten und Schmierölen am Beispiel hoch beanspruchter Ventililtriebskomponenten - Schulz, Edgar; Musayev, Yashar; Tremmel, Stephan; Hosenfeldt, Tim; Wartzack, Sandro; Meerkamm, Harald (DIAMOND BUSINESS, 2011)
UnivIS-Import:2015-03-09:Pub.2011.tech.FT.FT-KLMEFK.tribol

Truss Parametrization of Topology Optimization Results with Curve Skeletons and Meta Balls - Denk, Martin; Rother, Klemens; Paetzold, Kristin (Proceedings of the Design Society, 2022)
Truss-like shapes can occur in topology optimization described by an assembly of finite elements or its boundary represented as a polygon mesh. Such shape description does not cover a common engineering parametrization like the lines of a frame structure and its corresponding cross-section. This article addresses the truss-parametrization of such optimization using curve skeletons and Meta Balls. While the curve skeleton is common in the truss-parametrization, including Meta Balls can lead to an overall implicit and smooth shape description.<br
Keywords: topological optimisation; reverse engineering; computer-aided design (CAD)

Umsetzung der Digitalisierung in der Produktentwicklung - Gerschütz, Benjamin; Götz, Stefan; Wartzack, Sandro (Zeitschrift für wirtschaftlichen Fabrikbetrieb, 2023)
Product development is undergoing a transformation. The paradigm of virtual product development is increasingly moving towards digital engineering. However, Small and Medium Enterprises (SMEs) face problems in optimising their processes by integrating data-driven methods due to a lack of approaches for focused process analysis and method identification. The proposed approach provides a structured process to support the integration of data-driven methods in product development. The focus is on finding use cases in existing and established processes and on selecting suitable methods.<br
Keywords: Digitalization; Process Transformation; Digital Engineering; Product Development Process; SME

Uncertainty considerations by context factors for the monitoring of the degree of product maturity - Luft, Thomas; Reitmeier, Jochen; Paetzold, Kristin; Wartzack, Sandro (Proceedings of the DESIGN 2014 13th International Design Conference, 2014)
As the product development process is a knowledge and information handling process, information acquisition, processing and sharing is very important. However, information is often subject to uncertainty and influenced by the context. Therefore, this paper presents a novel approach for uncertainty considerations with contextual factors by using a matrix-based product description. This will be used to facilitate the situation-specific planning of virtual validations, an efficient monitoring of the degree of product maturity and the management of goal-oriented iteration cycles.
UnivIS-Import:2015-04-16:Pub.2014.tech.FT.FT-KLMEFK.uncert
Keywords: uncertainty; design structure matrix; property validation; maturity management; early design; decision making

Universal Design—An Old-Fashioned Paradigm? - Kett, Susan; Wartzack, Sandro (Emotional Engineering, 2017)
Universal Design is a strategy that intends to consider the heterogene-ous needs of users in our societies. Initially appearing during the civil rights movements in the 1950s, it focused firstly on physical accessibility and equality. Nowadays, subjective values addressing social inclusion or self-actualization are becoming more and more important. Stigmatization especially plays a major role in Universal Design’s acceptance, which is mainly emotion-driven. Therefore, modern Universal Design must aim for both the objective and the subjective well-being of users. In product design aspects of quality of life as a concept of success-ful user centring can help in considering various aspects of product quality, in-cluding subjectivity in particular. In this context an approach is provided to inte-grate attitudinal differences in users’ perception. Its impact on the modern Universal Design strategy is further considered by introducing a hierarchical product structure.
Keywords: Emotional Engineering; Universal Design; User centered Design; Quality of Life Technology

Unobtrusive Gait Reconstructions using Radar-based Optimal Control Simulations - Gambietz, Markus; Dröge, Anne; Schüßler, Christian; Stahlke, Maximilian; Wirth, Vanessa; Miehling, Jörg; Koelewijn, Anne (Asilomar Conference on Signals, Systems, and Computers, 2024)

Unterstützung der Auslegung von Wälzlagern durch elastohydrodynamische Simulation - Wirsching, Sven; Winkler, Andreas; Bartz, Marcel; Wartzack, Sandro (WiGeP News, 2022)

Unterstützung des Variantenmanagements von Elektromotoren durch wissensbasierte Systeme - Tüchsen, Johann; Dorsch, Julian; Obendorfer, Moritz; Schleich, Benjamin; Wartzack, Sandro (Design for X. Beiträge zum 30. DfX-Symposium 2019, 2019)
The automotive industry electrifies a huge variety of previously mechanically-actuated car functions. While sharing the same function. the used electric motors often differ in customer related geometries and interfaces. The suppliers have to cope with this huge external variance using an appropriate variant management. With this paper. the support of the variant management of electric drives by knowledge-based systems is proposed. Therefore. a combination of two systems containing the knowledge of the configuration and design of motors are used. The concept is applied and evaluated on the example of the shaft rotor lamination connection. As a result. the amount of internal variants can be reduced and controlled as well as the designer can be supported during the development process.<br
Keywords: Variant Management; Knowledge-based Systems; KBS; Electric Drives

Untersuchung des Reibungsverhaltens von Wälzlagern unter dem Einfluss von Zentripetalbeschleunigungen zur energieeffizienten Gestaltung von Lagerungen - Hochrein, David; Tremmel, Stephan; Graf-Goller, Oliver; Wartzack, Sandro (VDI - Berichte 2308, 2017)
Wälzlagerungen unter Zentripetalbeschleunigung haben wesentlichen Anteil an der Reibungsentstehung in Verbrennungsmotoren und Planetenradlagerungen. Aufgrund der komplexen Lastsituation sind Analysen bezüglich der Ursachen für die Reibungsentwicklung allerdings schwierig. Aus diesem Grund wurde ein Prüfstand entwickelt, mit dem einzelne Wälzlager unter dem Einfluss von bis zu 3000 g hinsichtlich Reibung anwendungsunabhängig untersucht werden können. Die Auswertung des dynamischen Ergebnissignals im Zeitbereich ist ohne Kenntnis der einzelnen Signalelemente nicht möglich. Daher ist es sinnvoll vom Zeitbereich in den Frequenzbereich zu wechseln. Dies geschieht durch Anwendung der Fast Fourier Transformation. Im Frequenzbereich werden die Signalkomponenten, sowie deren Einflussintensität sichtbar. Anhand dieses neuen Analyseansatzes lassen sich Einflussparameter auf die Wälzlagerreibung besser beurteilen.

Untersuchung des tribologischen Verhaltens wolframmodifizierter amorpher Kohlenstoffschichten (a-C:H:W) bei systematischer Variation der Biasspannung und des Argonflusses während des Beschichtungsprozesses - Zhao, Rong; Weikert, Tim; Tremmel, Stephan; Wartzack, Sandro (55. Tribologie-Fachtagung: Reibung, Schmierung und Verschleiß, 2014)
Metallmodifizierte wasserstoffhaltige amorphe Kohlenstoffschichten (DLC) werden als vielversprechende Kandidaten für die Beschichtung von Umformwerkzeugen angesehen. Sie zeichnen sich nicht nur durch geringe Eigenspannungen und gute Schichthaftung zum Substrat aus, sondern es ist auch möglich, ihre mechanischen Eigenschaften durch den Metallanteil in der amorphen Kohlenstoffmatrix einzustellen. Entsprechend dem aktuellen Stand der Forschung haben die Beschichtungsprozessparameter starken Einfluss auf die Struktur, die mechanischen Eigenschaften sowie das tribologische Verhalten der Schichten. In dieser Arbeit wurden wolframmodifizierte wasserstoffhaltige amorphe Kohlenstoffschichten (a‑C:H:W) auf Schnellarbeitsstahl (1.3343) durch reaktives Magnetronsputtern eines Wolframkarbidtargets in Ethin-Argon-Atmosphäre hergestellt. Hierbei wurden systematisch die Biasspannung und der Argonfluss jeweils in drei Stufen variiert. Anschließend fand eine mechanische und tribologische Charakterisierung der Schichtvarianten statt. Ihr Verschleißverhalten wurde unter trockenen und ölgeschmierten (mit und ohne Additivierung) Bedingungen untersucht. Dabei konnte ein jeweils unterschiedliches Verschleißverhalten beobachtet werden. Dieses ist insbesondere auf bestimmte tribochemische Reaktionen zwischen den abgeschiedenen Kohlenstoffschichten und den Additivkomponenten des Schmieröls zurückzuführen.
Keywords: Diamantähnlicher amorpher Kohlenstoff; Biasspannung; Stift-Scheibe-Versuch

Untersuchung des tribologisch-mechanischen Verhaltens amorpher Kohlenstoffschichten mittels Load Scanner - Wartzack, Sandro; Pejic, Goran; Durst, Karsten; Schaufler, Jens; Hetzner, Harald; Tremmel, Stephan (2012)
UnivIS-Import:2015-03-09:Pub.2012.tech.FT.FT-KLMEFK.unters

Untersuchungen an a-C:H:Me-beschichteten Rillenkugellagern unter Trockenlaufbedingungen - Kröner, Julia; Tremmel, Stephan; Wartzack, Sandro (Tribologie und Schmierungstechnik, 2019)
Under extreme environmental conditions or due to restrictions oil- or grease-lubricated standard rolling bearings can only be used to a limited extent or not at all. Existing solutions are expensive due to the special materials or lubricants used or have only a very limited service life. The alternative approach presented here involves the use of cost-effective standard rolling bearings, which have been modified with a friction and wear-reducing coating on individual components of the rolling bearing. Radial deep groove ball bearings of type 6206 are tested in operating life tests on a four bearing test rig. All investigated coating systems are described in the literature as basically usable under dry running conditions and normal atmosphere: Graphite, titanated molybdenum disulfide (MoS2:Ti), a modified (a-C:H:X) and a metal-containing hydrogen-containing amorphous carbon coating (a-C:H:Me). The different coating systems were applied to the raceways of the rolling bearing using PVD or PACVD processes and tested with both steel and ceramic balls. The results of these experiments in terms of operating life, tribological behaviour and, in particular, the repeatability of the results will be presented in this paper.<br
Keywords: Trockenlauf; Rillenkugellager; PVD-Beschichtung; Amorphe Kohlenstoffschicht; Bauteiltest; Vier-Lager- Prüfstand; Gebrauchsdauer

Untersuchungen an a-C:H:Me-beschichteten Rillenkugellagern unter Trockenlaufbedingungen - Kröner, Julia; Tremmel, Stephan; Wartzack, Sandro (60. Tribologie-Fachtagung 2019. Reibung, Schmierung und Verschleiß. Forschung und praktische Anwendungen., 2019)
Under extreme environmental conditions, such as very high or low temperatures, radiation and vacuum or due to restrictions, for example, in clean rooms, in the food and paper industries, oil- or grease-lubricated standard rolling bearings can only be used to a limited extent or not at all. Existing solutions are expensive due to the special materials or lubricants used or have only a very limited service life due to the reduction or avoidance of the mineral oil-based lubricant. The last-named is due to the omission of the positive properties of the lubricant, such as heat transport and friction reduction or wear reduction through separation of the surfaces. The alternative approach presented here involves the use of cost-effective standard rolling bearings, which have been modified with a friction and wear-reducing coating on individual components of the rolling bearing. The investigations described in this article focus on applications under normal atmosphere at room temperatures. Radial deep groove ball bearings of type 6206 are tested in operating life tests on a four-bearing test rig. All investigated coating systems are described in the literature as basically usable under dry running conditions and normal atmosphere: Graphite, titanated molybdenum disulfide (MoS2:Ti), a modified (a-C:H:X) and a metal-containing hydrogen-containing amorphous carbon coating (a-C:H:Me). In extensive screening tests, the a-C:H:Me coating has proven to be the best alternative in terms of lifetime. The different coating systems were applied to the raceways of the rolling bearing using PVD or PACVD processes and tested with both steel (100Cr6) and ceramic balls (silicon nitride - Si3N4) as counter bodies. The combination with ceramic balls was then followed up, as well as additional pairings, in which the steel balls were also provided with a-C:H:Me coating. The results of these experiments in terms of operating life, tribological behaviour and, in particular, the repeatability of the results will be presented in this paper. <br

Untersuchung von Tailored Surfaces hinsichtlich ihres tribologischen Einflusses auf Prozesse der Blechmassivumformung - Löffler, Maria; Freiburg, Dennis; Gröbel, Daniel; Loderer, Andreas; Matthias, Steffen; Stangier, Dominic; Weikert, Tim (18. Workshop Simulation in der Umformtechnik & 3. Industriekolloquium des SFB/TR73, 2015)
Die Analyse und gezielte Beeinflussung der tribologischen Bedingungen zwischen Werkzeug und Werkstück spielen bei der Entwicklung einer neuen Prozessklasse wie der Blechmassivumformung (BMU) eine entscheidende Rolle. Gerade für die Erweiterung der Bauteilfunktionalität bei blechmassivumgeformten Bauteilen stellen lokal angepasste tribologische Bedingungen eine Möglichkeit zur besseren Ausformung komplexer Bauteilgeometrien dar. Vor diesem Hintergrund unter-sucht der vorliegende Beitrag ausgewählte, maßgeschneiderte Oberflächen-modifikationen, sogenannte Tailored Surfaces, im Hinblick auf die Beeinflussung der tribologischen Eigenschaften unter Laborbedingungen. Basierend auf den gewonnen Erkenntnissen wurde eine als geeignet identifizierte Oberflächen-modifikation im realen Umformprozess auf ihre Anwendbarkeit zur Steuerung des Stoffflusses untersucht. Im Rahmen der Untersuchungen wurde die Wirksamkeit lokaler werkzeug- und werkstückseitiger Tailored Surfaces zur Steuerung des Stoffflusses bei einem ausgewählten Blechmassivumformprozess nachgewiesen.
Keywords: Tailored Surfaces; Tribologie; Blechmassivumformung

USE CASES FOR A HYBRID AUGMENTED REALITY COMPUTER WORKSTATION IN CAD WORKFLOWS - Harlan, Jakob; Götz, Stefan; Wartzack, Sandro (Proceedings of the Design Society, 2023)
Many immersive approaches for design activities show a great potential for their specific use cases, but still overall usage of extended reality technology in product developers day-to-day work is little. The user's workflow between classical desktop work environment and its immersive counterpart is interrupted by both a data gap and an interface gap. The three-dimensional product data usually needs preparation and the user has to physically change the interface in use. The hybrid augmented reality computer workstation aims to close these gaps. A hologram of the current model is visualized next to the screen in reach of the user for intuitive inspection and spatial interactions. In this paper we present use cases for this novel immersive workstation in the CAD workflow. An explorative user study of the typical product designer`s workflow reveals the most common activities. Guided by those, eight uses cases are formulated and classified into fundamental, drafting, and modelling CAD tasks. These cases include novel hybrid augmented reality interactions derived from literature, which are assessed with respect to their applicability.<br
Keywords: Computer Aided Design (CAD); Virtual reality; Workspaces for design; Augmeted Reality; Natural User Interfaces

Use of analytically describable geometries to calculate the contact between rolling element face and rib in bearing simulations - Wirsching, Sven; Schwarz, Sebastian; Tremmel, Stephan (Tribologie und Schmierungstechnik, 2020)
Depending on the load situation, the large number of contact points in rolling bearings contribute differently to the frictional power, temperature development and therefore the operating capacity of the rolling bearing. Under axial load, the contact between the roller and rib in particularly influences the operation and thus the frictional performance of a roller bearing, as it is the case with the new Angular Roller Unit (ARU) from Schaeffler. In existing programs for the dimensioning of rolling bearings, the contact calculation between the rolling element face and rib is usually based on the theory of HERTZ, although this is a simplification for complex geometries. This can lead to discrepancies in the calculation of deflections, contact surfaces and pressure compared to high quality numerical calculations (for example finite element analysis). In this paper a new, more accurate method for calculating the contact between the rolling element face and rib is presented and compared with the finite element method. The geometries are described analytically and form a substitute geometry which is pressed into a two-dimensional bedding following the approach of WINKLER. By means of the equilibrium of forces in the contact, similar to the work of POPOV, the contact area and the resulting pressure distribution can be calculated.<br
Keywords: Contact; pressure; friction; calculation and simulation methods; tapered roller bearings; bearings

Use of printed sensors to measure strain in rolling bearings under isolated boundary conditions - Bartz, Marcel; Halmos, Fabian; Jüttner, Michael; Ankenbrand, Markus; Häusler, Felix; Franke, Jörg; Wartzack, Sandro (Konstruktion, 2024)

Use of Printed Sensors to Measure Strain in Rolling Bearings under Isolated Boundary Conditions - Bartz, Marcel; Häußler, Felix; Halmos, Fabian; Ankenbrand, Markus; Jüttner, Michael; Roudenko, Jewgeni; Wirsching, Sven; Reichenberger, Marcus; Franke, Jörg; Wartzack, Sandro (Lubricants, 2023)
The knowledge of the operating conditions in rolling bearings in technical applications offers many advantages, for example, to ensure a safe operation and to save resources and costs with the help of condition monitoring and predictive maintenance procedures. In many cases, it is difficult to implement sensors to measure the operating conditions of the rolling bearing, for reasons such as inaccessibility of the mounting position or non-compliance with installation space neutrality, which influences the sensor on the measuring point. Printed sensors using a digital deposition process, which can be used in very narrow design spaces, offer advantages in this respect. So far, these sensors have not been established in rolling bearings, so there is potential for technical application. This paper discusses the fundamental advantages and disadvantages as well as the challenges of the application, and it demonstrates the feasibility under isolated boundary conditions by applying a printed strain gauge sensor to the outer ring of a cylindrical roller bearing NU210 in an experimental setup to measure the strain under load. In this setup, the outer ring is deformed by 2 mm under an increasing radial load using a hydraulic press, and the strain is measured. Both a commercial reference sensor and a FE-simulation are used to validate the measurement. The results show that an implementation using printed sensors as a strain gauge works successfully. The resulting challenges, such as measuring strain gradients and printing on curved surfaces, are finally evaluated, and an outlook for further work is given.<br
Keywords: rolling bearings; sensor-integrated machine elements; strain measurement; printed strain gauges; printed sensors

Using exact macroscopic geometry in elastohydrodynamic simulations of point and elliptical contacts - Wirsching, Sven; Bartz, Marcel (Tribologie und Schmierungstechnik, 2023)
In rib-guided roller bearings, there are a large number of different tribological contact forms. These include not only line contacts on the raceways, the cage and the rolling elements, but also point and elliptical contacts between the rolling element end face and the ring rib. Load is transmitted via these lubricated, concentrated rolling and rolling-sliding contacts. Depending on the load situation, these contacts contribute differently to the operating behavior of the roller bearing. Axial loads on rib-guided roller bearings are mainly transmitted via the point and elliptical contacts between the roller end and the ring rib. These oil-lubricated point and elliptical contacts can be calculated and designed using thermos-elastohydrodynamic (TEHD) simulations. In existing methods for the TEHD calculation of point and elliptical contacts, the macroscopic geometries of the contact partners are described in a simplified manner, similar to the theory according to HERTZ, using ellipsoids. However, contacts of real, complex geometry pairings of rolling elements and ribs, as used to optimize the axial load capacity or the frictional torque of roller bearings, can only be determined inaccurately with this method. Compared to the exact consideration of the macroscopic geometry, larger discrepancies in the lubricant film height, contact pressure and friction can be observed. For this reason, this paper presents a TEHD simulation that considers the exact macroscopic geometry of point or elliptical contacts. The macroscopic geometry is generated using mathematical functions and a ray-tracing method is used to generate the equivalent body for the TEHD simulation. Different geometry pairings of sphere, plane, cone and torus are investigated. The results for lubricant film height, contact pressure and friction are compared with the results from conventional TEHD simulations, which use a geometry description via ellipsoids. By comparing the calculated geometry pairings, the possibilities and limitations of the modified geometry description are assessed. Bei bordgeführten Rollenlagern existiert eine Vielzahl von unterschiedlichen tribologischen Kontaktformen. So sind nicht nur Linienkontakte an den Laufbahnen, dem Käfig sowie den Wälzkörpern, sondern auch Punkt- und Ellipsenkontakte zwischen Wälzkörperstirnfläche und Ringbord vorhanden. Die Kraftübertragung erfolgt über diese geschmierten, konzentrierten Wälz- und Wälz-Gleit-Kontakte. Abhängig von der Belastungssituation tragen diese Kontakte unterschiedlich zum Betriebsverhalten des Rollenlagers bei. Axiale Lasten auf bordgeführte Rollenlager werden vorwiegend über die Punkt- und Ellipsenkontakte zwischen Rollenstirn und Ringbord übertragen. Diese ölgeschmierten Punkt- und Ellipsenkontakte können mit Hilfe von Thermo-Elastohydrodynamik (TEHD) Simulationen berechnet und ausgelegt werden. Bei bestehenden Methoden der TEHD Berechnung von Punkt- und Ellipsenkontakten werden die makroskopischen Geometrien der Kontaktpartner vereinfacht, ähnlich der Theorie nach HERTZ, über Ellipsoide beschrieben. Kontakte realer, komplexer Geometriepaarungen von Wälzkörper und Ringbord, wie sie zur Optimierung der axialen Belastbarkeit oder des Reibungsmomentes von Rollenlager eingesetzt werden, lassen sich damit allerdings nur ungenau ermitteln. Im Vergleich zur exakten Berücksichtigung der makroskopischen Geometrie sind größere Diskrepanzen in der Schmierfilmhöhe, des Kontaktdrucks und der Reibung zu verzeichnen. Aus diesem Grund wird in diesem Beitrag eine TEHD Simulation vorgestellt, welche die exakte makroskopische Geometrie des Punkt- bzw. Ellipsenkontaktes berücksichtigt. Die makroskopische Geometrie wird mit Hilfe von mathematischen Funktionen erzeugt und über ein Ray-Tracing Verfahren der Ersatzkörper für die TEHD Simulation generiert. Verschiedene Geometriepaarungen aus Kugel, Ebene, Kegel und Torus werden untersucht. Die Ergebnisse für Schmierfilmhöhe, Kontaktdruck und Reibung werden mit den Ergebnissen aus herkömmlichen TEHD Simulationen, welche eine Geometriebeschreibung über Ellipsoide verwendet, verglichen. Durch den Vergleich der berechneten Geometriepaarungen werden die Möglichkeiten und Grenzen der veränderten Geometriebeschreibung beurteil
Keywords: Elastohydrodynamik (EHD); Kontakt; Reibsysteme; Berechnungs- und Simulationsmethoden; elastohydrodynamics; contact; friction systems; calculation and simulation methods; bearings

Using Machine Learning for Product Portfolio Management: A Methodical Approach to Predict Values of Product Attributes for Multi-Variant Product Portfolios - Mehlstäubl, Jan; Braun, F.; Denk, Martin; Kraul, R.; Paetzold, Kristin (Proceedings of the Design Society, 2022)
To satisfy customer needs in the best way, companies offer them an almost infinite number of product variants. Although, an identical product was not built before, the values of its attributes must be determined during the product configuration process. This paper introduces a methodical approach to predict the values of product attributes based on customer feature configurations using machine learning. Machine learning reduces the effort compared to rule-based expert systems and is both, more accurate and faster. The approach was validated by predicting vehicle weights using industrial data.<br
Keywords: machine learning; portfolio management; product development; artificial intelligence (AI); data-driven design

Using Machine Learning Methods for Predicting Cage Performance Criteria in an Angular Contact Ball Bearing - Schwarz, Sebastian; Grillenberger, Hannes; Graf-Goller, Oliver; Bartz, Marcel; Tremmel, Stephan; Wartzack, Sandro (Lubricants, 2022)
Rolling bearings have to meet the highest requirements in terms of guidance accuracy, energy efficiency, and dynamics. An important factor influencing these performance criteria is the cage, which has different effects on the bearing dynamics depending on the cage’s geometry and bearing load. Dynamics simulations can be used to calculate cage dynamics, which exhibit high agreement with the real cage motion, but are time-consuming and complex. In this paper, machine learning algorithms were used for the first time to predict physical cage related performance criteria in an angular contact ball bearing. The time-efficient prediction of the machine learning algorithms enables an estimation of the dynamic behavior of a cage for a given load condition of the bearing within a short time. To create a database for machine learning, a simulation study consisting of 2000 calculations was performed to calculate the dynamics of different cages in a ball bearing for several load conditions. Performance criteria for assessing the cage dynamics and frictional behavior of the bearing were derived from the calculation results. These performance criteria were predicted by machine learning algorithms considering bearing load and cage geometry. The predictions for a total of 10 target variables reached a coefficient of determination of R2≈0.94" role="presentation">R2≈0.94 for the randomly selected test data sets, demonstrating high accuracy of the models.
Keywords: Wälzlager; Maschinelles Lernen; Käfiginstabilität; Künstliche neuronale Netze; Random Forest; Gradient Boosting; Evolutionäre Algorithmen

Using machine learning to increase efficiency in design of experiments for cyclic characterization of fibre-reinforced plastics - Gadinger, Marc; Witzgall, Christian; Hufnagel, Thomas; Wartzack, Sandro (Proceedings of the 34th Symposium Design for X (DFX2023), 2023)
Efficient characterization of fatigue behavior plays a crucial role in engineering design as it reduces the financial costs associated with expensive experimental tests. Existing methods for characterizing the fatigue behavior of fibre-reinforced plastics have proven inefficient due to the oversight of important design parameters, such as fibre orientations. To address this challenge, we propose an innovative approach based on Gaussian process regression. Our approach integrates previously unaccounted design parameters into the decision-making process, ensuring that optimal design points are selected for testing. By doing so, we maximize the gain of knowledge within the model, resulting in improved efficiency and accurate characterization of fatigue behavio
Keywords: fatigue behavior; machine learning; gaussian processes; fibre-reinforced plastics

Utilization of MBSE Models for a Micro-Mobility Solution in the Context of System of Systems - Wilking, Fabian; Horber, Dennis; Schleifer, Simon; Behringer, Marc; Miehling, Jörg; Götz, Stefan; Wartzack, Sandro (2024 19th Annual System of Systems Engineering Conference (SoSE), 2024)
The adoption of Model-Based Systems Engineering (MBSE) methodologies, particularly employing system models such as those represented by SysML diagrams, holds significant promise in comprehending the intricacies inherent in the development of technical systems. However, a thorough evaluation of the advantages of MBSE is imperative to rationalize the implementation endeavors associated with MBSE methodologies. With the Utilization of system models, the concept of using system models in different application scenarios apart from the initial model purpose as well as other lifecycle stages is feasible. In the realm of System of Systems (SoS), where the complexity is notably elevated, it is fundamental to generate comprehensive models that elucidate the interdependencies among systems. This undertaking necessitates an extension of the conventional Utilization of system models with an adaptation to the unique challenges presented by SoS. This research introduces an approach that extends the Utilization of system models to SoS-models, elucidating feasible scenarios.<br
Keywords: Model-Based Systems Engineering; MBSE; System of Systems; SysML; Mobility

Utilization of RFLP in V-Model methodology for the interdisciplinary development of Digital Twins - Fett, Michel; Wilking, Fabian; Götz, Stefan; Wartzack, Sandro; Kirchner, Eckhard (Forschung Im Ingenieurwesen-Engineering Research, 2025)
Digital Twins have numerous potentials like performance analysis, condition monitoring or process optimization. As the development of Digital Twins is a highly interdisciplinary task, it poses challenges and is therefore rarely utilized. This contribution considers the interdisciplinary development of Digital Twins as an interplay between sensors, models and IT infrastructure. It builds on previous publications that deal with the domains of models, sensors and IT infrastructures in the context of Digital Twins as well as domain-specific development procedures. For this purpose, the V‑model of VDI 2206 is used and modified for the context of the Digital Twin. In order to integrate the findings of the preliminary work into the V‑model at a more concrete level, they are sorted into an RFLP framework, which in turn is integrated into the V‑model. The resulting development approach covers the entire development process at a transferable, abstract level, while at the same time providing concrete steps at a directly applicable level. The results are illustrated using an exemplary application of an industrial gearbox.
CRIS-Team Scopus Importer:2025-03-14

Utilization of SysML System Models for Smart Assembly Using Digital Twins - Wilking, Fabian; Kaup, Simon; Fett, Michel; Götz, Stefan; Kirchner, Eckhard; Wartzack, Sandro (DS 130: Proceedings of NordDesign 2024, Reykjavik, Iceland, 12th - 14th August 2024, 2024)
Digital Twins are a promising technology to increase the value of products and create new business models. As models are an essential component of these Digital Twin concepts, the reuse of models is necessary. With this contribution, a methodical approach for the integration of a manufacturing structure into a system model is introduced for early verification activities. Furthermore, a novel utilization concept for transforming SysML models into discrete event models is presented to enable assembly simulations. In addition, it is embedded into a use case scenario for a Digital Assembly Twin.<br
Keywords: Systems Engineering (SE); Digital Manufacturing; Product-Service Systems (PSS); Assembly Process; SysML

Utilization of system models in model-based systems engineering: definition, classes and research directions based on a systematic literature review - Wilking, Fabian; Horber, Dennis; Götz, Stefan; Wartzack, Sandro (Design Science, 2024)
The use of system models within model-based systems engineering (MBSE) is essential for improved communication or system documentation. Previous publications have investi- gated further reuse of these system models, for example, transforming them directly into discipline-specific models for reuse. The authors refer to this as the term “Utilization” of system models. It aims the compensation of modelling efforts and a further integration of linked models within MBSE. Motivated by a lack of common understanding of this term, a systematic literature review of the state of the art is presented. With this systematic overview, a definition and classification system for different use cases and system life cycle stages are created. These are key results to support engineers and researchers in adopting existing or discovering new utilization approaches. This supports the mission of advanced systems engineering and aims the identification of new research directions coming along with SysML v2 and the advanced systems engineering methods.
Keywords: Model-based systems engineering; MBSE; Systems engineering; System models; SysML

Utilizing System Models for Multicriteria Decision-Making - A Systematic Literature Review on the Current State of the Art - Horber, Dennis; Pickel, Jessica; Götz, Stefan; Wartzack, Sandro (IEEE Open Journal of Systems Engineering, 2024)
The rising system complexity of modern products requires new approaches within model-based systems engineering to manage the upcoming challenges. System development is characterized by a wide variety of decisions to be made. These situations have to be modeled within a holistic system model to ensure traceability. Motivated by lack of a comprehensive overview of approaches, this paper presents the results of a systematic literature study focusing on utilizing system models in decision-making. By that, the existing gap between theoretical foundations and implementation in practical use is intended to be closed through providing practitioners insights to relevant approaches. Apart from that, researchers are enabled to derive new research directions from the corpus of literature. Relevant reports use different diagrams to model a decision situation or its processes and reuse those diagrams as well as their contents to feed methods from multi-criteria decision-making. By that, new objectives are added to those diagrams, namely to enable extensive decision-making, which is understood as their utilization. Thus, this paper provides an overview of applied decision-making approaches, languages used to model the decision context and the use of external tools, where the decision-making algorithms are executed. The findings show that the majority of existing approaches only cover certain aspects of the decision-making situation in the system model and especially the formalization of the decision-making process is hardly considered. Besides that, future research fields including the analysis of potentials coming along with the introduction of SysML v2 and especially its API are identifie
Keywords: decision-making; model-based systems engineering (MBSE); multi-criteria decision-making (MCDM); product development

Utilizing the Embodiment Function Relation and Tolerance Model for Robust Concept Design - Li, Jiahang; Horber, Dennis; Keller, Christoph; Grauberger, Patric; Götz, Stefan; Wartzack, Sandro; Matthiesen, Sven (Proceedings of the Design Society, 2023)
The early use of Robust Design (RD) supports the development of product concepts with low sensitivity to variation, which offers advantages for reducing the risk of costly iterations. Due to the lack of approaches for early evaluation of product robustness, the embodiment-function-relation and tolerance (EFRT-) model was developed, which combines the contact and channel approach and tolerance graphs. The information exchange of both approaches offers a high potential for reliable robustness evaluation results. However, that potential currently relies unused, since the link between applicable robustness criteria and the extended information is missing. To solve this problem, four research steps were determined: (1) understanding of robustness, (2) collection of RD principles, (3) identification of EFRT-model information and (4) mapping of RD principles and information. The results show nine adapted RD principles, the identified model information for the robustness evaluation, the evaluation criteria as well as their mapping. Utilizing the mapping and the proposed criteria in this contribution, a more comprehensive robustness evaluation in early stages is enable
Keywords: Robust Design; Conceptual Design; Product Modelling / Models; Variation Management; Contact and Channel Approach

Validierung eines Ansatzes zur Simulation kurzfaserverstärkter Thermoplaste in frühen Entwurfsphasen - Witzgall, Christian; Wartzack, Sandro (Design for X. Beiträge zum 26. DfX-Symposium, 2015)
A simplified approach towards a simplified integrative simulation for short fibre reinforced polymers (SFRP) has been proposed by Gruber and Wartzack. It uses orientation information from injection moulding simulation directly inside a structural or crash simulation. For describing the complex material behavior of SFRP, a layerwise stacking of simple material models is used. Thus, only standard material models which can be computed efficiently have to be used. Within the present paper, the simulative approach is to be verified and validated, i.e. the physical plausibility and the usability for loadcases with elevated strain rates are examined.

Validierung von prozessgerecht strukturoptimierten Bauteilentwürfen mittels integrierter FEM-Realgeometrieanalyse - Hautsch, Stefan; Katona, Sebastian; Sprügel, Tobias; Koch, Michael; Rieg, Frank; Wartzack, Sandro (Design for X. Beiträge zum 26. DfX-Symposium, 2015)
The structural optimization as a tool of the virtual product development process (PDP) provides broad possibilities to scoop leightweight design and improvement potentialities when developing new products. To promote the further dissemination of structural optimization, the focus of the developments lies on a process-ready structural optimization, which does not only aim at design, safeguarding and later alteration through process restrictions , but at a straightforward generation of a process- and production-ready part by using computer-aided optimization tools. This efficient approach in product development helps to reduce iterations in the PDP, but also brings along the need for a validation of the newly created procedure because manufacturing processes like forming often cause deviations in the physical part which were not regarded in the dimensioning of the desired part. Hence the established simulation of the desired component design (based on 3D CAD data) should be supplemented with a simulation of the physical part geometry (based on the 3D scan of a prototype). The overvalue of the current development is a efficiency increase of the product development process through a reduction of iteration loops and effective generation of process-, production- and utilization-ready part designs with the aid of structural optimization tools and a knowledge database, illustrated exemplarily by the forming process. The finite element (FE) analysis of the desired geometry is joined by a validation of the adapted product development process by geometry analysis and FE-simulation of the physical geometry provided by a 3D scanner. Consequently, the deviations made by the manufacturing process can be analyzed for their relevance for the part's performance and the design can be safeguarded.
Keywords: validation; finite element analysis; structural optimization; 3D scan

Variant Value Management to Optimize Compexity and Value of Product Families - Luft, Thomas; Schmied, Christian; Schöberl, Maximilian; Wartzack, Sandro; Zimmermann, Markus; Mörtl, Markus (23rd INTERNATIONAL DEPENDENCY AND STRUCTURE MODELING CONFERENCE, DSM 2021, 2021)

Variation Analysis of Design Parameters of Fibre-Reinforced Plastic Parts - Franz, Michael; Schleich, Benjamin; Wartzack, Sandro (Proceedings of the 22nd International Conference on Engineering Design (ICED19), 2019)
Lightweight Design as an engineering domain is becoming more and more important in terms of sustainable mobility. Therefore, a large number of researchers is developing methods for utilisation of modern, but as well more complex materials with high lightweight potential. One subgroup of these materials are fibre-reinforced plastics (FRP). A lot of work is done supporting the design engineer in exploiting the structural and mechanical behaviour as good as possible. Whereas variations of laminate parameters, resulting from production, are poorly studied. Their impact especially on defined measures under load is of high importance, e.g. having a look on clearances in automotive industry. Because of the high complexity of FRP-parts, resulting from many laminate parameters, tolerancing is not an intuitive process. This is reflected in the fact that there is no defined procedure for tolerancing of FRP-parts. To support the design engineer the authors perform sensitivity analysis for simple loadcases to identify layers with a high importance on a defined measure. The results then are generalised to provide general guidelines to the design enginee

Verbesserungspotentiale in der Entwicklung und Validierung hoch dynamisch belasteter Leichtbaukomponenten im Umfeld der Zulieferindustrie - Gruber, Georg; Walter, Michael; Wartzack, Sandro (Design for X. Beiträge zum 21. DfX-Symposium, 2010)
UnivIS-Import:2015-04-16:Pub.2010.tech.FT.FT-KLMEFK.verbes

Vereinfachte Simulation von Klebeverbindungen an Hybridstrukturen durch Einsatz von Metamodellen - Witzgall, Christian; Merklein, Annette; Resch, Thomas; Starost, Stephan; Kellermeyer, Markus; Vogt, Jürgen; Most, Thomas; Will, Johannes; Wartzack, Sandro (Simulation und Erprobung in der Fahrzeugentwicklung 2016, 2016)

Vergleichende Studie der Topologie-Optimierungsalgorithmen CONLIN und SUMT - Gruber, Georg; Stockinger, Andreas; Tremmel, Stephan; Wartzack, Sandro (Tagungsband zum 5. Landshuter Leichtbau-Colloquium, 2011)
UnivIS-Import:2015-04-16:Pub.2011.tech.FT.FT-KLMEFK.vergle

Verification of a passive ankle-foot orthosis design method by using truss models - Scherb, David; Steck, Patrick; Wartzack, Sandro; Miehling, Jörg (28th Congress of the European Society of Biomechanics, 2023)
Passive ankle-foot orthoses (AFOs) are the most common treatment option for people suffering from foot drop. By holding the foot in a neutral position and thereby preventing its drop, a significant improvement of the patients’ gait pattern and comfortable gait speed can be realised [1]. However, the effect is limited and a discrepancy remains compared to the gait of healthy people [2]. Thus, active AFOs driven by motorsand external power supply were developed, which allow for adjustability of the required ankle position. Their disadvantages, as high weight or difficult power supply, have inhibited their use in daily life so far [3]. Therefore, we develop a novel passive AFO that is equipped with supporting structures providing an adjustable assistance for patients. The main requirement for the new design is to provide an appropriate assistance for the patients’ needs, i.e. to match the support required by the patient and transfer this support through the product to the patient. A popular tool for investigating the effects of orthoses and similar devices (referred to as wearable assistive devices) are digital human models, allowing to study the biomechanical outcomes of the assistance [4]. In this way, a conceptual method was developed that enables the design of the passive AFO’s supporting structures in accordance with the pathological situation of the patients. This contribution aims to verify the method by using truss models of the passive AFO for different patients’ conditions. The elaborated method enables the integration of finite element models in musculoskeletal human models (MHMs) to design the passive AFO. To save computing time, the design of an AFO was discretized for each patient with beam elements and subsequently the number of beams was minimized by means of topology optimization (see Figure 1). The musculoskeletal human models are created from motion capture recordings of subjects in a gait laboratory. By biomechanical analysis of the gait records, the kinematics and externally applied loads at the truss models during the gait cycle are determined. The resulting stresses and deformations are calculated with these boundary conditions in the truss models and the resulting reaction forces are then applied as external forces to the MHM Thereby, the biomechanical effects of the assistance with a truss model of the AFO can be simulated. By comparing the results, the verification of the method is realized. Therefore, the relation between the provided support to previously determined assistance-as-needed calcu-lations [5] are examined. The results of the truss support show an activation of the plantarflexor muscles from 20 - 60 % of the gait cycle, referred to as the stance phase and no activation after 60 % of the gait cycle, the swing phase (see Figure 1). The supporting forces and torque depict the majority of provided assistance in the stance phase of the gait cycle and a minor part in the swing phase of gait cycle. The good agreement of resulting biomechanical effects of the truss AFO model simulations (muscle activations and provided support torque) compared to data from previous assistance-as-needed calculations (Figure 1) verify the developed passive AFO design method. Thus, the functionality of the method for providing design suggestions and the possibility to depict the interaction between MHM and AFO is proven. In the next validation step, model order reduced finite element models of the AFO will be used to incorporate a more realistic behaviour of the AFO design in the simulation.<br

Verification of the Accuracy of FE-Models in Bulk-Forming of Micropins from Sheet Metal - Kraus, Martin; Hufnagel, Thomas; Merklein, Marion (WCMNM 2018 World Congress on Micro and Nano Manufacturing, doi: 10.3850/978-981-11-2728-1_02, 2018)
LFT Import::2019-08-07 (2307)

Verification of the Accuracy of FE-Models in Bulk-Forming of Micropins from Sheet Metal - Kraus, Martin; Hufnagel, Thomas; Merklein, Marion (World Congress on Micro and Nano Manufacturing - WCMNM 2018, 2018)

Versagensprognose bei der Crashsimulation von Kunststoff Türsystemen zur Erschließung des Leichtbaupotenzials in Fahrzeugen - Wartzack, Sandro (VDI-Bericht, 2008)
UnivIS-Import:2015-04-16:Pub.2008.tech.FT.FT-KLMEFK.versag

Verschiedene Rollen im Wissensmanagement – eine bibliografische Studie - Luft, Thomas; Wartzack, Sandro (Wissensmanagement - Magazin für Führungskräfte, 2014)
• Schon die Tatsache, dass Wissen subjektiv – also personengebunden – ist, zeigt wie untrennbar Wissensmanagement vom Menschen bzw. Mitarbeiter ist. [18, 19] • Nicht nur aus empirischer bzw. industrieller Sicht sondern auch aus bibliographischer bzw. wissenschaftlicher Sicht lässt sich eine Vielzahl unterschiedlicher Rollenbeschreibungen für das Wissensmanagement finden. • In einer bibliographischen Studie wurden verschiedene Rollenbeschreibungen im Wissensmanagement erarbeitet und sowohl hinsichtlich ihrer Bezeichnungen und Zuständigkeiten als auch im Hinblick auf ihre jeweiligen Aufgabenbereiche und damit einhergehend auch Kompetenzen und Verantwortlichkeiten beleuchtet.
Keywords: Wissensmanagement; Wissensmanager; Wissensingenieur; Rollen; bibliografische Studie

Verschleißmodellierung mischreibungsbehafteter Maschinenelemente am Beispiel eines Axial-Zylinderrollenlagers - Winkler, Andreas; Bartz, Marcel; Wartzack, Sandro (VDI-Berichte 2378, 2021)
Keywords: Verschleißsimulation; Mischreibung; Wälzlager

Verschleißsimulation grenz- und mischreibungsbehafteter Wälzkontakte - Winkler, Andreas; Bartz, Marcel; Wartzack, Sandro (Tribologie und Schmierungstechnik, 2021)
Im Rahmen dieses Beitrags wird ein Vorgehensmodell zur numerischen Verschleißberechnung von Wälzkontakten vorgestellt. Das FEM-basierte Verschleißsimulationsmodell von Winkler [1] wird um die Möglichkeit erweitert, neben mischreibungsbehafteten Kontakten auch grenzreibungsbehaftete Kontakte zu berücksichtigen. Am Beispiel eines Axial-Zylinderrollenlagers und zweier Lastfälle werden Ergebnisse einer Verschleißmodellierung sowohl im Mischreibungsgebiet als auch im Grenzreibungsgebiet präsentier
Keywords: Verschleißmodellierung; Kontaktmechanik; Elastohydrodynamik (EHD); Mischreibung; Grenzreibung; Wälzlager

Verschleißsimulation grenz- und mischreibungsbehafteter Wälzkontakte - Winkler, Andreas; Bartz, Marcel; Wartzack, Sandro (62. Tribologie-Fachtagung 2021, 2021)
Keywords: Verschleißsimulation; Mischreibung; Grenzreibung; Wälzlager

Verwendung der exakten makroskopischen Geometrie in Elastohydrodynamic Simulationen von Punkt- und Ellipsenkontakten - Wirsching, Sven; Bartz, Marcel (63. Tribologie-Fachtagung, 2022)
Im Inneren von bordgeführten Rollenlagern existiert eine Vielzahl von unterschiedlichen tribologischen Kontaktformen. So sind nicht nur Linienkontakte an den Laufbahnen, dem Käfig sowie den Wälzkörpern, sondern auch Punkt- und Ellipsenkontakte zwischen Wälzkörperstirnfläche und Ringbord vorhanden. Die Kraftübertragung erfolgt über diese geschmierten, konzentrierten Wälz- und Wälz-Gleit-Kontakte. Abhängig von der Belastungssituation tragen diese Kontakte unterschiedlich zum Betriebsvermögen des Rollenlagers bei. Axiale Lasten auf bordgeführte Rollenlager werden vorwiegend über die Punkt- und Ellipsenkontakte zwischen Rollenstirn und Ringbord übertragen. Diese ölgeschmierten Punkt- und Ellipsenkontakte können mit Hilfe von Elastohydrodynamik (EHD) Simulationen berechnet und ausgelegt werden. Bei bestehenden Methoden zur Berechnung der EHD von Punkt- und Ellipsenkontakten werden die makroskopischen Geometrien der Kontaktpartner vereinfacht, ähnlich der Theorie nach Hertz, über Ellipsoide beschrieben. Kontakte realer, komplexer Geometriepaarungen von Wälzkörper und Ringbord, wie sie zur Optimierung der axialen Belastbarkeit oder des Reibungsmomentes von Rollenlager eingesetzt werden, lassen sich damit allerdings nur ungenau ermitteln. Im Vergleich zur exakten Berücksichtigung der makroskopischen Geometrie sind größere Diskrepanzen in der Schmierfilmhöhe, des Kontaktdrucks und der Reibung zu verzeichnen. Aus diesem Grund wird in diesem Beitrag eine EHD Simulation vorgestellt, welche die exakte makroskopische Geometrie des Punkt- bzw. Ellipsenkontaktes berücksichtigt. Die makroskopische Geometrie wird, wie bereits von Wirsching vorgestellt, mit Hilfe von mathematischen Funktionen erzeugt und über ein Ray-Tracing Verfahren der Ersatzkörper für die EHD Simulation generiert. Verschiedene Geometriepaarungen aus Kugel, Ebene, Kegel und Torus werden untersucht. Die Ergebnisse für Schmierfilmhöhe, Kontaktdruck und Reibung werden mit den Ergebnissen aus herkömmlichen EHD Simulationen, welche eine Geometriebeschreibung über Ellipsoide verwendet, verglichen. Durch den Vergleich der berechneten Geometriepaarungen werden die Möglichkeiten und Grenzen der veränderten Geometriebeschreibung beurteilt.<
Keywords: elastohydrodynamics; contact; friction systems; calculation and simulation methods; bearings

Virtual Assessment of Product Use Based on Biomechanical Human Models - Wartzack, Sandro; Krüger, Daniel; Miehling, Jörg (Anais do 19. Seminário International de Alta Tecnologia, 2014)

Virtual planning and evaluation of human work Virtuelles Planen und Bewerten menschlicher Arbeit - Wolf, Alexander; Miehling, Jörg; Wartzack, Sandro; Quadrat, Eric; Nolte, Alexander; Fritzsche, Lars; Bauer, Sebastian; Spitzhirn, Michael; Peters, Markus; Leidholdt, Wolfgang; Wischniewski, Sascha (Arbeitsmedizin, Sozialmedizin, Umweltmedizin, 2019)
CRIS-Team Scopus Importer:2024-12-16

Virtual Validation Of Functional Automotive Door Assembly Properties By Means Os Superosed CAT And FEM Analysis - Ehlert, Matthias; Heling, Björn; Wartzack, Sandro (Proceedings of the 20th International Conference on Engineering Design (ICED 15) Vol 4: Design for X, Design to X, 2015)
As with all industrially manufactured goods, it is generally necessary to ensure costumer requirements are met. Therefore, it is important to ensure that functional as well as optical specifications of a product are fulfilled for large quantities in series production. The following piece of work demonstrates the effect that the elasticity of an assembly has on specific functional criteria in order to meet the aim of a robust design. For this purpose an automotive door assembly is examined, where tightness is one of the most relevant attributes from the customer’s perspective. In the present case, the effect of the elastic sealing system on the development of the limiting positions of the observed assembly that result from a corresponding tolerance analysis will be examined in greater detail which, in turn, has an impact on tightness. The term ‘limiting position’ generally describes the largest deviation from the nominal dimension that can occur with a high level of statistical probability. To that end, a simulation-based integrated process is introduced that covers CAT as well as FEM methods and in this way respects the elasticity of the system with its corresponding deformation.
Keywords: Computer aided design (CAD); Robust design; Virtual engineering (VE); Computer aided tolerancing (CAT)

Virtuelles Planen und Bewerten menschlicher Arbeit - Wolf, Alexander; Miehling, Jörg; Quadrat, Eric; Nolte, Alexander; Fritzsche, Lars; Bauer, Sebastian; Spitzhirn, Michael; Peters, Markus; Leidholdt, Wolfgang; Wischniewski, Sascha; Wartzack, Sandro (Arbeitsmedizin, Sozialmedizin, Umweltmedizin, 2019)
Die ergonomische Gestaltung von Arbeitsplätzen ist eine Grundvoraussetzung zur Vorbeugung von Erkrankungen des Muskel-Skelett-Systems durch körperliche Arbeit. In diesem Beitrag wird das Forschungs- und Entwicklungsprojekt „ema2AnyBody“ vorgestellt, in dem ein Softwaretool zur virtuellen Planung und Bewertung menschlicher Arbeit entwickelt wird. Das Besondere dabei: Die Bewertung kann anhand biomechanischer Beanspruchungsgrößen erfolgen, die mithilfe einer automatisierten biomechanischen Simulation erhoben werde

Virtuelle Toleranzbeurteilung abweichungsbehafteter Bauteile - Schleich, Benjamin; Wartzack, Sandro (Design for X - Beiträge zum 23. DfX-Symposium - Oktober 2012, 2012)
Geometric deviations are observable on every manufactured part and can have huge influences on the functional behaviour of technical products. Therefore, allowable limits for these imperfections have to be specified and set during product development. However, this task is quite difficult since geometric deviations affect the product behaviour in various ways. Thus, current approaches try to incorporate the whole workpiece geometry in tolerance activities instead of reducing the functional behaviour by expressing it as vector chains. In this context, the virtual assessment of geometric deviations is an important step in geometry-based computer aided tolerancing. This contribution illustrates the methodology as well as some applications of virtual tolerance assessment and highlights the possibilities and advantages of geometry-based tolerancing.
UnivIS-Import:2015-04-16:Pub.2012.tech.FT.FT-KLMEFK.virtue

Virtuelle und experimentelle Toleranzuntersuchungen abweichungsbehafteter Baugruppen - Heling, Björn; Schleich, Benjamin; Wartzack, Sandro (Industriekolloquium der Forschergruppe FOR 2271, 2019)

Vision Toleranzmanagement 4.0 - Wartzack, Sandro (Konstruktion, 2017)

Visualisation of biomechanical stress quantities within CAD environments - Krüger, Daniel; Wartzack, Sandro (Proceedings of the 20th International Conference on Engineering Design (ICED15) Vol.10, 2015)
The demographic development in many industrialised societies and markets with a growing power of the customers augments the importance of user-centred design approaches. In this regard it is crucial for design engineers to understand how the use of a product is affecting the prospective user physically and emotionally. In this contribution an attempt is made to quantify physical effects on the human body during the interaction with technical systems. We present an approach to visualise biomechanical stress quantities obtained from simulations with musculoskeletal human models within CAD engineering environments. The objective is to enable designers to intuitively estimate how their solutions will influence the physical state of the user. The topic is relevant for the design of technical artefacts that are characterised by a close interaction with people. This comprises ergonomic questions in product design but also the planning of manufacturing processes as well as the development of medical devices for training and rehabilitation
UnivIS-Import:2015-10-26:Pub.2015.tech.FT.FT-KLMEFK.visual
Keywords: CAD; visualisation; biomechanics; ergonomics

Visuelle Unterstützung der Toleranzanalyse in der industriellen Anwendung - Striegel, Serena; Schleich, Benjamin; Ehlert, Matthias; Zielinski, Daniel; Wartzack, Sandro (Summer School Toleranzmanagement - Beiträge zur 3. Summer School - September 2017, 2017)

Vom Ideal- zum Realmodell: Bauteile mit Fertigungsabweichungen durch automatische FE-Netzadaption simulieren - Katona, Sebastian; Kestel, Philipp; Koch, Michael; Wartzack, Sandro (Entwerfen Entwickeln Erleben – Beiträge zu virtuellen Produktentwicklung und Konstruktionstechnik, 2014)

Vom schließmaßbasierten Toleranzmanagement zum eigenschaftsbasierten Robust Design - Ziegler, Philipp; Wartzack, Sandro (Design for X. Beiträge zum 24. DfX-Symposium, 2013)
UnivIS-Import:2015-04-16:Pub.2013.tech.FT.FT-KLMEFK.vomsch

Voraussetzungen für den Einsatz datengetriebener Methoden in der Produktentwicklung - Mehlstäubl, Jan; Nicklas, Simon; Gerschütz, Benjamin; Sprogies, Nicolai; Schleich, Benjamin; Lohner, Thomas; Wartzack, Sandro; Stahl, Karsten; Paetzold, Kristin (Proceedings of the 32nd Symposium Design for X (DFX2021), 2021)
Data mining and machine learning are successfully applied in many business areas such as marketing or production. Due to the increasing complexity in data and information flows and the large amount of data, data-driven solutions have also great potential in product development. Nevertheless, many companies are not able to integrate data-driven methods into their product development process. In order to support the application of data-driven methods, this paper identifies necessary prerequisites for their integration in product development. Based on a data analysis process, the prerequisites are elaborated and, subsequently, levers for their design are derive
Keywords: Data-driven Methods; Product Development; Data Mining; Machine Learning

Vorgehensweisen zur Vorhersage menschlicher Bewegung durch muskuloskelettale Simulation - Wolf, Alexander; Miehling, Jörg; Wartzack, Sandro (Design for X. Beiträge zum 28. DfX-Symposium, 2017)
Musculoskeletal simulations are holding the capability to quantify man-machine interactions of systems which are not build yet. Thus, they have the capability to be an important CAE-tool in product development. The most common approach of musculoskeletal simulations is the inverse dynamic analysis. Unfortunately this approach has view disadvantages, which are the main reason why musculoskeletal simulations are not in broad application yet. The main disadvantage is that measurements have to take place for every simulation. To overcome the measurements for inverse dynamics, movement and external forces have to be predicted. We present two approaches for motion prediction and describe which of them is more suitable to match the needs of product development.
Keywords: musculoskeletal simulation; posture- and movement-prediction; human centered design; man–machine interaction

Vorgehen zur Validierung von Toleranzanalyseverfahren von Mechanismen - Heling, Björn; Schleich, Benjamin; Wartzack, Sandro (Konstruktion, 2021)
Das Toleranzmanagement bietet die Möglichkeit, die Folgen von unweigerlich auftretenden geometrischen Abweichungen prädiktiv bei der Produktentwicklung zu berücksichtigen und gezielt zu steuern. Dazu werden Toleranzanalyseverfahren eingesetzt, die eine Überlagerung der geometrischen Bauteil- und Prozessabweichungen und deren Folgen für die Produktqualität virtuell abbilden. Der vorliegende Beitrag zeigt erstmalig eine Möglichkeit auf, wie diese Toleranzanalyseverfahren validiert werden können.<br

Vorstellung der Forschergruppe "Prozessorientiertes Toleranzmanagement mit virtuellen Absicherungsmethoden“ - Wartzack, Sandro; Heling, Björn; Schleich, Benjamin (Industriekolloquium der Forschergruppe FOR 2271, 2019)

Vorstellung einer neuen Prüfstandsgruppe zur Untersuchung des Fliehkrafteinflusses auf das Reibungsmoment von Wälzlagern - Hochrein, David; Graf-Goller, Oliver; Tremmel, Stephan; Wartzack, Sandro (Tribologie und Schmierungstechnik, 2017)
Anwendungen in denen Wälzlager Fliehkraftbelastung erfahren sind beispielsweise Planetenradlagerungen oder Pleuellagerungen im Verbrennungsmotor. Im Bereich der Getriebetechnik sind die Anforderungen an Planetenradlagerungen vor allem in den letzten Jahren aufgrund von Wirkungsgradoptimierungen stark angestiegen und die zu ertragenden Beschleunigungen werden in wenigen Jahren Werte bis zum 8 000‑fachen der Erdbeschleunigung erreichen. Dies entspricht in etwa einer Verdoppelung der aktuellen Belastung. Im Gegensatz hierzu sind die Anforderungen für Pleuellagerungen schon seit Beginn der Entwicklung von Verbrennungsmotoren sehr komplex. Im Bereich der Kraftfahrzeugmotoren haben sich daher in den vergangenen Jahrzenten überwiegend Gleitlager etabliert, obwohl zu Beginn der Motorenentwicklung diese Anwendung eine Domäne der Wälzlager war. In beiden Anwendungen sind fliehkraftbelastete Wälzlager ein wesentlicher Beitragsleister für das Gesamtreibungsmoment des Aggregats und weisen somit ein vielversprechendes Energieeinsparpotential auf. Aufgrund der extremen und komplizierten Belastungen sind die Vorgänge in solchen Lagern bisher allerdings nur wenig erforscht. Aus diesem Grund ist eine Prüfstandsgruppe entwickelt und gebaut worden, die eine intensive experimentelle Untersuchung dieser Thematik erlaubt.
Keywords: Wälzlager; Reibung; Fliehkraftfeld

Vorstellung einer neuen Prüfstandsgruppe zur Untersuchung des Fliehkrafteinflusses auf das Reibungsmoment von Wälzlagern - Hochrein, David; Graf-Goller, Oliver; Tremmel, Stephan; Wartzack, Sandro (57. Tribologie-Fachtagung. Reibung, Schmierung und Verschleiß. Forschung und praktische Anwendungen, 2016)
Anwendungen in denen Wälzlager Fliehkraftbelastung erfahren sind beispielsweise Planetenradlagerungen oder Pleuellagerungen im Verbrennungsmotor. Im Bereich der Getriebetechnik sind die Anforderungen an Planetenradlagerungen vor allem in den letzten Jahren aufgrund von Wirkungsgradoptimierungen stark angestiegen und die zu ertragenden Beschleunigungen werden in wenigen Jahren Werte bis zum 8 000‑fachen der Erdbeschleunigung erreichen. Dies entspricht in etwa einer Verdoppelung der aktuellen Belastung. Im Gegensatz hierzu sind die Anforderungen für Pleuellagerungen schon seit Beginn der Entwicklung von Verbrennungsmotoren sehr komplex. Im Bereich der Kraftfahrzeugmotoren haben sich daher in den vergangenen Jahrzenten überwiegend Gleitlager etabliert, obwohl zu Beginn der Motorenentwicklung diese Anwendung eine Domäne der Wälzlager war. In beiden Anwendungen sind fliehkraftbelastete Wälzlager ein wesentlicher Beitragsleister für das Gesamtreibungsmoment des Aggregats und weisen somit ein vielversprechendes Energieeinsparpotential auf. Aufgrund der extremen und komplizierten Belastungen sind die Vorgänge in solchen Lagern bisher allerdings nur wenig erforscht. Aus diesem Grund ist eine Prüfstandsgruppe entwickelt und gebaut worden, die eine intensive experimentelle Untersuchung dieser Thematik erlaubt.
Keywords: Wälzlager; Reibung; Fliehkraftfeld

Was macht ein Wissensingenieur? - Luft, Thomas; Wartzack, Sandro (Wissensmanagement - Magazin für Führungskräfte, 2015)
• Das bewusste und effiziente Managen des Wettbewerbsfaktors „Wissen“ ist eine immer wichtiger werdende sozio-kulturelle und organisatorische Managementaufgabe. [2, 9, 11] • In einer empirischen Studie wurden verschiedene Rollenbeschreibungen im Wissensmanagement erhoben und sowohl hinsichtlich ihrer Bezeichnungen und Zuständigkeiten als auch im Hinblick auf ihre jeweiligen Aufgabenbereiche und damit einhergehend auch Kompetenzen und Verantwortlichkeiten analysiert. • Im Fokus des vorliegenden Beitrags stehen insbesondere die Aufgaben der Rolle des  Wissensingenieurs und die an diese Rolle gestellten Anforderungen.
Keywords: Wissensingenieur; Wissensarbeiter; Wissensmanagement; Berufsbild

Wear Detection using Carbon-Based Sensor Coatings – a novel approach - Weikert, Tim; Tremmel, Stephan (Proceedings of The 18th Nordic Symposium on Tribology – NORDTRIB 2018, 2018)
This study focusses on carbon-based sensor coatings, which allow the detection of wear by an increase in electrical resistance. Coatings comprise high- and low-resistance layers of chromium or tungsten carbide, respectively, and silicon doped amorphous carbon. In repeated scratch tests, wear could most significantly be detected in Cr-containing sensor coatings. Short circuits to the substrate necessitated a sufficient thickness of the high-resistance layer for a significant detection of the coating’s wear. In summary, the advantageous tribological behavior of DLC coatings can be expanded by a sensory function for wear detection, to ensure a prolonged and individual lifetime of DLC-coated components.<br
Keywords: Wear; Sensor Coating; Carbon-Based Coating