Determination of strain dependent anisotropy in layer compression tests and resulting influence on the yield locus modelling - Lenzen, Matthias; Merklein, Marion (2019)
LFT Import::2019-08-05 (2361)

Determination of the biaxial anisotropy coefficient using a single layer sheet metal compression test - Hetz, Peter; Lenzen, Matthias; Kraus, Martin; Merklein, Marion (19th International Conference on Sheet Metal, SheMet 2021, 2021)
Keywords: Anisotropy; Metal forming; Material characterization

Determination of the heat transfer during hot stamping - Geiger, Manfred; Merklein, Marion; Hoff, Cornelia (Steel-Future for the Automotive Industry, 2005)
LFT Import::2019-08-05 (1179)

Determination of the mechanical properties of hot stamped parts from numerical simulations - Hagenah, Hinnerk; Merklein, Marion; Lechner, Michael; Schaub, Adam; Lutz, Stefan (Procedia CIRP, 2015)
Hot stamping is a well-established process in car manufacturing today. However, the resulting mechanical properties of a hot stamped part and its behaviour during a crash are still open questions. The usual procedure includes destructive experiments to determine the mechanical properties resulting from the forming and quenching process. The gained information is then used for crash simulation. Using images from micrographs to determine the proportion of bainite and martensite resulting from the hot stamping process has proved to be difficult, as these structures are fairly similar and hard to distinguish. Sophisticated numerical simulations of the hot stamping process are available. The hardness resulting from the hot stamping process can be predicted fairly well from these process simulations. However, information like the tensile strength that is more relevant for the crash behaviour cannot be predicted that easily. It is not yet state of the art to map the results from the hot stamping simulation directly into the crash simulation. The approach to be presented in detail in this contribution uses the forming speed and the quenching velocity to predict the relevant mechanical properties of the hot stamped parts. Both input parameters, the forming speed and the quenching velocity, can be derived from the numerical hot stamping simulation. By means of experiments using a thermomechanical test system Gleeble well defined process parameters were used. Micro tensile test specimens were manufactured out of the Gleeble specimens to eliminate the effect of the Gaussian temperature profile created during the Gleeble experiments. Afterwards, tensile tests were carried out to derive a response surface for 22MnB5. The validated results allow the determination of the tensile strength of hot stamped parts from the numerical simulation of the hot stamping process with good accuracy.
LFT Import::2019-07-29 (2013)
Keywords: Hot stamping; Simulation

Determination of the properties of semi-finished parts in blanking processes - Wiesenmayer, Sebastian; Frey, Philipp; Lechner, Michael; Merklein, Marion (IOP Conference Series: Materials Science and Engineering, 2020)

Determination of thermal and mechanical material properties if ultra high strength steels for hot stamping - Lechler, Jürgen; Merklein, Marion; Geiger, Manfred (Steel Research International, 2008)
Direct and indirect hot stamping presently constitutes one of the most innovative forming technologies in the automotive industry through the combination of forming and hardening in one process step or line. Thus, structural components with strength up to 1600 MPa can be accomplished with the quench hardenable ultra-high strength steel 22MnB5. With respect to the numerical investigation of the feasibility of different parts the knowledge of various thermal and mechanical material characteristics determined under process relevant conditions are required. Within the scope of this paper different experimental methods will be introduced for the determination of material properties according to the typical time-temperature characteristics of the hot stamping process, as well as the modelling of it as input data for the FE analysis.
LFT Import::2019-07-29 (1561)
Keywords: 22MnB5; Flow behaviour; Heat transfer; Hot stamping; Modelling

Determination of the tensile properties for the weld line of tailored welded blanks - Tolazzi, Massimo (ESAFORM 2005, Proceedings of the 8th ESAFORM Conference, Trondheim, Norway, 2005)
LFT Import::2019-08-05 (1174)

Determination of tribological conditions within hot stamping - Geiger, Manfred; Merklein, Marion; Lechler, Jürgen (Production Engineering, 2008)
Innovative hot sheet metal forming technologies are gaining an increasing significance in the scope of application of more and more innovative high and ultra high strength steels in the automotive industry. With respect to a numerical process design beside the mechanical and the thermal material characteristics the friction coefficient represents an important input parameter for finite element (FE) simulation. Within the scope of this paper an evaluation method for the determination of the friction coefficient μ for the direct hot stamping process of boron-manganese steels will be presented. Therefore cup deep drawing tests at elevated temperatures following the time-temperature-characteristic of the hot stamping process are carried out. For the calculation of the friction coefficient the approach according to Siebel for the modeling of the maximum drawing force is used. © German Academic Society for Production Engineering (WGP) 2008.
LFT Import::2019-07-29 (1553)
Keywords: Friction coefficient; Hot stamping; Production process

Determination of Yield Loci of Sheet Metal at Elevated Temperatures by the Integration of a Diode Laser Source - Hußnätter, Wolfgang; Merklein, Marion; Geiger, Manfred (Proceedings of AMPT 2006, 2006)
LFT Import::2019-08-05 (1264)

Determining the properties of multi-range semi-tubular self-piercing riveted joints - Kappe, Fabian; Wituschek, Simon; Bobbert, Mathias; Meschut, Gerson (Production Engineering, 2022)
By applying a variety of strategies, including both the development of new drive concepts as well as the use of lightweight constructions, it is intended to meet the climate targets set by the Paris Agreement. Multi-material design is often used when applying lightweight constructions, especially in the mobility sector. Herby, various materials with different properties are combined to well adapt the structure to the application of force in order to reduce weight. For example, this can result in the combined use of (high-strength) steel and aluminium. However, the increasing number of materials used and the number of resulting joints has led to the development of a number of different joining processes. These can only be used to a limited extent for joining multi-material joints and are usually inflexible facing changing boundary conditions. Examples of further difficulties affecting the established processes are metallurgical incompatibilities, which particularly pose difficulties for the use of thermal joining processes. A frequently used mechanical joining process is self-piercing riveting. Due to its high load-bearing capacities, a wide range of application and high process robustness it is often used when joining of dissimilar material is required. However, in case of self-piercing riveting used, the increasing number of multi-material joints and material-thickness combinations leads to the need of a large number of rivet-die-combinations to adapt the joining process to the respective joining task. Since the joining system cannot react to these changes, a tool change or an adjustment of the system is necessary, which leads to a reduction in efficiency and extended process times. To increase flexibility and process efficiency, new, versatile joining technologies are needed that can be adapted to changing boundary conditions. One possibility for this is the use of multi-range capable semi-tubular self-piercing rivets, which are inserted into the joint by using a new joining system with extended punch-sided actuator technology. The increased actuator technology enables the rivet to be set by an inner punch and subsequently to form a rivet head by embossing with an outer punch. All punch movements can be controlled independently of each other, enabling adaptive adjustment of the process parameters. Depending on the rivet geometry used, rivet head formation by the outer punch can be performed both with and without head deformation. The rivet without head deformation consists of a tubular shape with ring grooves in the rivet head area. Using the outer punch, punch-sided material is formed into the ring grooves creating an interlock in the head area of the rivet. The rivet with head deformation is designed differently. It is modified to enable subsequent forming to the respective thickness of the joint by forming the protrusion of the rivet head onto the punch-sided joining part. In the study presented here, the joining process of the versatile self-piercing riveting is presented, analysed and the property profile of the joints is determined on the basis of various material-thickness combinations. Here, both the characteristic parameters of the joints and the joint load-bearing capacities are determined. Finally the property profiles are compared with conventionally manufactured joints in order to identify potential for improvement.
CRIS-Team WoS Importer:2022-02-18

Developing a computer aided design system for actuator design for laser micro adjustment - Plettke, Raoul; Hagenah, Hinnerk; Geiger, Manfred (Proceedings of the 18th CIRP International Design Seminar (March 2008), 2008)
LFT Import::2019-08-05 (145)

Developing LBM process parameters for Ti-6Al-4V thin wall structures and determining the corresponding mechanical characteristics - Ahuja, Bhrigu; Schaub, Adam; Karg, Michael; Lechner, Michael; Merklein, Marion; Schmidt, Michael (Physics Procedia, 2014)
The Laser Beam Melting (LBM) process technology within the family of Additive Manufacturing technology is characterized by its ability to fabricate fully dense 3D structures directly from micro-sized metal powder. With the current state of the art, Ti-6Al-4V has been processed using LBM machine systems constituting a laser with a beam diameter of about 100 μm. In order to fabricate structures with smaller wall thicknesses, processing of Ti-6Al-4V is attempted on the LBM machine system, Realizer SLM 50 consisting of a laser with a beam diameter 10 μm. The proposed paper presents the development of process parameters for fabricating fully dense Ti-6Al-4V 3D structures using the LBM machine system, Realizer SLM 50. Further experiments are carried out to determine the wall thickness and mechanical properties achievable using the selected process parameters. Analysis and scientific arguments are presented to explain the influence of building direction and heat treatment on mechanical propertie
Keywords: Laser Beam Melting; titanium alloy; mechanical characterization

Development and Evaluation of Tool Sided Surface Modifications for Dry Deep Drawing of Steel and Aluminum Alloys - Merklein, Marion; Schmidt, Michael; Wartzack, Sandro; Tremmel, Stephan; Andreas, Kolja; Häfner, Tom; Zhao, Rong; Steiner, Jennifer (Dry Metal Forming Open Access Journal, 2015)

Development and launching of an application-oriented test rig for wear investigations in sheet-bulk metal forming - Merklein, Marion; Andreas, Kolja; Kraus, Martin; Löffler, Maria; Pilz, Florian (THE"A" Coatings, 2017)
LFT Import::2019-08-05 (2256)

Development of a Biaxial Tensile Machine for Characterization of Sheet Metals - Merklein, Marion; Biasutti, Manfredi (Journal of Materials Processing Technology, 2013)
A new stand-alone biaxial testing machine with out-of-plane loading system has been developed to study the anisotropic plastic behavior of metal sheets on cruciform specimens. In this apparatus a single screw driven actuator is used and the variation of the load ratio along the two main directions is achieved by adjusting the geometry of a link mechanism. This design firstly combines the advantages of biaxial displacement devices, typically mounted in a universal tensile tester, with stand-alone machines and by at the same time providing a solution to the limitations associated with each of these types. The used specimen is discussed and compared through numerical simulations to a prominent geometry proposed in the literature. Experiments are presented and the results are implemented in identifying classical and advanced yield criteria and though represented as yield surfaces. © 2012 Elsevier B.V.
LFT Import::2019-07-29 (1862)
Keywords: Biaxial tensile machine; Cruciform specimen; Sheet metal

Development of a Control Strategy for Laser Beam Melt Ablation Based on Process Modelling - Cser, Adrienn Orsolya; Otto, Andreas; Geiger, Manfred (Proceedings of the 4th CIRP International Seminar on Intelligent Computation in Manufacturing Engineering. ICME' 2004. Sorrento, Italy, 2004)
LFT Import::2019-08-05 (1052)

Development of a damage prediction system for bending and cutting of high strength steels - Vatter, Peter; Hildering, Sven; Tsoupis, Ioannis; Merklein, Marion (Key Engineering Materials, 2013)
The application of modern high-strength low-alloy steels (HSLA) and advanced high strength steels (AHSS) for structural and safety relevant components in the automotive industry offers the advantage of combining low specific weight with high material strength. Typical manufacturing processes for these steel grades are bending and cutting operations. However, the forming and cutting potential of these innovative steel grades is different to conventional steels as the process and the damage behaviour is changing. In bending operations cracks occur at the outer bending edge, whereas in cutting operations delamination can appear at the sheared edge, which can initiate component failure. In the scope of this work a method is presented to describe the damage behaviour of both, bending and cutting operations, by theoretical meta models. In order to generate a database experiments were carried out using a typical HSLA. The main influencing factors have been varied experimentally, such as the rolling direction, normalised bending radius and punch to die clearance. To calculate further sampling points a finite element model has been developed and validated against the experimental data. The damage criterion of LemaÎtre has been applied. The necessary parameters were determined by reverse numerical identification by means of the major strain for the bending operation and by the punch force-punch stroke curve for the cutting operation. To build up a system for the prediction of the damage the gained data basis was approximated by mathematical functions. An error analysis was carried out showing good accordance. In doing so, a meta model for the evaluation of the damage rate could be established. The functions were implemented in a software tool which allows the user to determine the failure probability for a given parameter set. This software tool is exemplarily validated against experimental air bending tests using a higher normalised bending radius. Copyright © 2013 Trans Tech Publications Ltd.
LFT Import::2019-07-29 (1853)
Keywords: Bending; Cutting; Damage prediction; High strength steel

Development of a feature adapted measurement evaluation strategy - Loderer, Andreas; Hausotte, Tino; Steinmann, Paul; Merklein, Marion; Landkammer, Philipp; Hildenbrand, Philipp; Schneider, Thomas (MacroScale 2014 - Recent developments in traceable dimensional measurements, 2015)
This article describes a methodical approach for developing a feature adapted measurement evaluation strategy using the example of a multi-scale multi-sensor fringe projection system. In a first step calibrated standard features were selected and measured in the next step by different fringe projection sensors with varying measuring range and resolution. For selecting which sensor is most appropriate for which feature the standard deviation as well as the deviation between calibrated values and measured values were considered. Finally the results were summarized in a decision matrix, which helps to select a feature adapted measurement strategy.

Development of a new analytical model for plane strain microbending - Onyancha, R. M.; Kinsey, B. L.; Engel, Ulf (4M/ICOMM 2009, Proceedings of the Global Conference on Micro Manufacture, 2009)
The design of efficient manufacturing processes requires the development and use of accurate process models. Using an established macroscale model, a new microscale bending model is proposed. For macroscale (fine grained) material undergoing bending the surface regions experience severe strain while the interior sections suffer less straining because the grain boundaries inhibit the dislocation motion. For the microscale (coarse grained specimens) there are fewer grain boundaries in the interior of the specimen therefore the dislocations can more easily and uniformly penetrate into the interior leading to an increased deformation in the interior section of the specimen. This therefore means that there is a smaller but more linear strain gradient from the surface to the neutral axis of the specimen. The new model accounts for some of these size effects by assuming a linear strain distribution through the specimen thickness, and a flow stress that is a function of the grain size. Using a flanging operation, with CuZn15 specimens that were 0.1 mm, 0.25 mm and 0.5 mm thick with varying numbers of grains through the thickness, this new analytical model was verified to more accurately predict the peak force in a microbending operation as compared to the established macroscale models.
LFT Import::2019-08-05 (1579)
Keywords: Microbending; Microflanging; Size effects

Development of a New Method for Producing Plane Expanded Metal by Laser Cutting and Forming of Metal Plates under Uniaxial Tension - Merklein, Marion; Junker, Daniel; Schaub, Adam; Kretschmer, Anne; Lechner, Michael (Key Engineering Materials, 2015)
The on-going trend to lightweight construction leads to a special focus on plane lattice structures as an alternative for solid metal plates. They demonstrate similar mechanical properties while taking up only a fraction of the normal material input and are thus economically favourable. Additionally, they fulfil functional and design aspects and therefore are used by several industries like the automobile. Nevertheless, the two most common types of lattice structures-perforated metal plates and expended metal plates-Are either waste intensive or uneven and hence require additional rolling of the metal plate. Therefore, within this contribution a new and innovative approach for the production of plane lattice structures will be presented. The manufacturing process thereby consists of two steps. At first, a specially designed pattern is cut into metal plates via a laser. Subsequently, the plates are formed under uniaxial tension to realize the lattice structures. Based on the cutting length, cutting space and the row space different blanks with tailored lattice structures can be produced. From the experimental results first guidelines for the design of suitable patterns are derived. The investigations will be performed with precipitation hardenable aluminium AA6014.
LFT Import::2019-07-29 (2118)
Keywords: Design method; Lattice structure; Metal forming

Development of an irradiation strategy withing a closed loop control system for the laser adjustment of deformation - Hutterer, Angelika; Hagenah, Hinnerk; Geiger, Manfred (Proceedings of the 2003 International Conference on Control, Automation and Systems (ICCAS 2003), 2003)
LFT Import::2019-08-05 (947)

Development of a novel forming tool for the production of high-strength aluminum components with tailored properties - Rigas, Nikolaos; Merklein, Marion (IOP Conference Series: Materials Science and Engineering, 2024)
Because of growing environmental and technical requirements, the efficient manufacturing of components with tailored properties using recyclable materials is mandatory. The combination of high-strength aluminum alloys and thermal-assisted forming operations is an innovative method for the production of components with varying mechanical properties. By locally adjusting the cooling rates during a thermo-mechanical forming operation, it is possible to modify the microstructure and precipitation conditions. A subsequent aging operation causes different microstructural and mechanical characteristics. This allows both deep-drawing and adjustment of the component properties in one single step. For this reason, this contribution focuses on the production of components with tailored properties. With the aid of a non-contact measuring system, previous investigations have proved that mechanical material properties can be adapted during a forming process by adjusting the cooling rates. In this contribution, this knowledge is transferred to a novel temperature-controlled rectangular cup tool. A variation of the local tool temperature and holding duration in the tool will be carried out. Then, the mechanical and microstructural properties of the manufactured components will be characterized through hardness and DSC investigations. In addition, the influence of different tool temperatures on the component temperature, the sheet thickness distribution and process forces will be investigated. As a result, it has been demonstrated that mechanical, process-related and geometric advantages can be achieved by using locally temperature-controlled forming tools.<br

Development of a novel in-situ measurement method for thermo-mechanically coupled material characterization of high-strength aluminum alloys - Rigas, Nikolaos; Garcin, Thomas; Kuball, Clara-Maria; Merklein, Marion (IOP Conference Series: Materials Science and Engineering, 2023)
High-strength aluminum alloys are more and more used for safety and crash-relevant components due to their advantageous density-to-strength ratio. By using thermal-supported forming strategies, failure-free deep drawing is possible for these materials. In this context, the hot form quench process (HFQ®) has shown to be a promising thermally-assisted forming strategy. By using locally tempered forming tools, the production of tailored components with different mechanical properties is possible. However, material characterization and process design with conventional characterization methods are quite challenging in this context. A new approach is the use of ultrasound-assisted material characterization in combination with a thermo-mechanical simulator. Thereby it is possible to perform an in-situ material characterization. So far, this technology is mainly used for steel materials. In this contribution, the potential of an adapted measurement strategy for high-strength aluminum alloys is presented. For this purpose, the influence of different measurement parameters on modified samples and the resulting measurement signal is investigated. With the help of this study, new standards are set for time-bound material characterization under thermo-mechanical stress. As a result, thermally-assisted forming methods can be designed more efficiently and faster in the futur

Development of a Process Model for Laser Beam Melt Ablation - Geiger, Manfred; Cser, Adrienn Orsolya; Otto, Andreas (Production Engineering. Annals of the German Academic Society for Production Engineering, 2005)
LFT Import::2019-08-05 (1235)

Development of a testing method for the identification of friction coefficients for numerical modeling of the shear-clinching process - Müller, Martin; Vierzigmann, Ulrich; Hörhold, Réjane; Meschut, Gerson; Merklein, Marion (Key Engineering Materials, 2015)
LFT Import::2019-07-29 (2108)
Keywords: Joining; Sheet Metal; Tribology

Development of Irradiation Strategies for 3D-Laser Forming - Hennige, Thomas (Sheet Metal 1998: Proceedings of the 6th International Conference on Sheet Metal, 1998)
LFT Import::2019-08-05 (1605)

Development of irradiation strategies for 3D-laser froming - Hennige, Thomas (Journal of Materials Processing Technology, 2000)
LFT Import::2019-07-15 (812)

Diagnostik der Werkstücktemperatur beim thermischen Abtragen mit CO2-Hochleistungslasern - Kauf, Michael; Hartmann, W.; Biermann, Stefan; Geiger, Manfred; Christiansen, J. (DPG, 1990)
LFT Import::2019-08-05 (736)

Diagnostik und Regelung beim Laserstrahlschweißen - Otto, Andreas; Hohenstein, Ralph; Dietrich, Simon (Strahltechnik Band 28, Tagungsband zum 5. Laser-Anwendeforum, 2006)
LFT Import::2019-08-05 (1328)

Dickblechumformen und Formhärten - Potentiale und Grenzen bei der Herstellung hochbelasteter Funktionsbauteile - Wieland, Michael; Merklein, Marion (6. Erlanger Workshop Warmblechumformung, 2011)
LFT Import::2019-08-05 (1775)

Die Bedeutung der Gasführung beim Laserstrahlschneiden von kurzglasverstärkten Verbundwerkstoffen - Müller, Roland; Geiger, Manfred (Laser und Optoelektronik, 1990)
LFT Import::2019-08-05 (739)

Diesseits und jenseits der Umformtechnik - Geiger, Manfred; Merklein, Marion; Nock, Marco (Lange währt die Umformtechnik, 2004)
LFT Import::2019-07-16 (1097)

Die Zukunft der Fertigung liegt auf dem Tisch - Menschig, A.; Fröhlich, Thomas; Ludwig, J.; Paasche, N.; Weber, M.; Zimmermann, M. (Mikroproduktion, 2008)
LFT Import::2019-07-29 (1548)

Diodenlaser in der Praxis - Hierl, Stefan; Fröhlich, Thomas; Eßer, Gerd (Euro-Laser, 2001)
LFT Import::2019-07-15 (883)

Discontinuous laser dispersing of titanium nitride based hard ceramic particles for improving the tribological behavior of hot stamping tools - Schirdewahn, Stephan; Carstensen, Niels; Spranger, Felix; Hilgenberg, Kai; Merklein, Marion (Hot Sheet Metal Forming of High-Performance Steel, 2022)
Over the last decades, the application of ultra-high strength steel (UHSS) has constantly increased within the automotive industry due to its favorable strength-to-weight ratio. For manufacturing such steel grades to complex-shaped body-in-white parts, temperature-assisted forming operations are required. In this regard, hot stamping has been established as a suitable technology to generate geometrical complex car body components with high shape accuracy. During the forming operation, however, high thermo-mechanically tool stresses appear, which in turn promote the occurrence of severe wear and high friction values at the blank-die interface. Within short production periods, the quality of the parts as well as the operating time of the tool are negatively affected. For this purpose, an innovative surface engineering technology named laser implantation has been applied, in order to improve the tribological performance of hot stamping tools. The implantation technique is based on manufacturing highly wear-resistant, separated and elevated microfeatures onto the tool surface by embedding hard ceramic particles via pulsed laser radiation. To qualify the resulting tribological behavior, modified pin-on-disk tests have been performed under hot stamping conditions. Afterwards, optical and tactile measurements of the blank surface as well as Energy-dispersive X-ray spectroscopy (EDS) analysis on the worn tool topography have been carried out to clarify the cause-effect relations. The results have been compared to unmodified tooling systems, in order to evaluate the tribological impact of the laser implantation process. <

Distributed Ledgers für den Materialdatenaustausch - Lechner, Michael; Frey, Philipp; Kreß, Maximilian; Christ, Tassilo; Charlet, Christoph; Merklein, Marion (wt Werkstattstechnik - Online, 2021)
Moderne industrielle Fertigungsprozesse müssen stetig wachsende Anforderungen an Material- und Ressourceneffizienz, Qualität und Variantenvielfalt erfüllen. Die unternehmensübergreifende Zusammenführung integritätsgesicherter Daten ist hierbei Voraussetzung für die retrospektive Identifikation von Qualitätsproblemen, die Dokumentation der Einhaltung von Standards und die Allokation von Ressourcenverbräuchen entlang der Wertschöpfungskette. In diesem Beitrag wird am Beispiel eines Materialcharakterisierungsverfahrens für den hybriden Leichtbau diskutiert, wie mit der Blockchain- Technologie ein manipulationssicheres Speicherkonzept umgesetzt werden kann.<br
Keywords: Werkstoffe; Digitalisierung; Industrie 4.0

Double Sheet Hydroforming of Complex Hollow Parts - Celeghini, Martino; Geiger, Manfred (Journal of the Japan Society for Technology of Plasticity, 2003)
LFT Import::2019-07-15 (944)

Drawing Capability of High Formable Packaging Steel: Comparison of Limiting Drawing Ratio and Forming Limit Curve - Knieps, Fabian; Köhl, Manuel; Merklein, Marion (Key Engineering Materials, 2022)
To assess the suitability of different packaging steels for complex deep drawing applications, nowadays, the total elongation and the Lankford coefficients in simple tensile tests are used. However, the simple use of uniaxial tensile tests is not supposed to predict the limiting drawing ratio precisely and thus the suitability for deep drawing applications. At the same time, the conduction of limiting drawing ratio experiments is extensive and requires a high testing effort. Therefore, in this work, the correlation between the forming limit curve results were compared to the results of limiting drawing ratio experiments to predict the formability of packaging steel by a much simpler criterion. At the same time, different approaches to calculate the plane strain forming limit by tensile test data were used to assess the drawing capability of packaging steel. Results revealed a strong correlation between the measured plane strain forming limit and the limiting drawing ratio at a fixed blank holder force. However, calculation methods based on tensile test data were not able to predict the drawing capability sufficiently.
CRIS-Team Scopus Importer:2023-03-29
Keywords: Deep Drawing; Forming Limit Curve; Packaging Steel

Dreidimensionale Oberflächenanalyse bei Feinblechen. - Geiger, Manfred; Pfestorf, Markus; Engel, Ulf (Stahl und Eisen, 1995)
LFT Import::2019-07-15 (552)

Druckversuch bei erhöhten Temperaturen - Schaub, Adam; Lechner, Michael; Merklein, Marion (Tagungsband Werkstoffprüfung DGM, 2013)
LFT Import::2019-08-05 (1919)

Dry Film Lubricants in Aluminium Sheet Metal Forming - Geiger, Manfred; Meiler, M.; Pfestorf, Markus; Merklein, Marion (Proceedings of the 3rd International Conference THE Coatings in Manufacturing Engineering, 2002)
LFT Import::2019-08-05 (1720)

Dual beam Nd:YAG laser welding: Influence of lubricants to lap joint welding of steel sheets - Geiger, Manfred; Merklein, Marion; Otto, Andreas; Blankl, Andreas (Proceedings of the XVI. International Symposium on Gas Flow and Chemical Lasers & High Power Laser Conference, Gmunden, Austria, 2006)
LFT Import::2019-08-05 (1313)

Ductile Damage and Fatigue Behavior of Semi-Finished Tailored Blanks for Sheet-Bulk Metal Forming Processes - Besserer, Hans-Bernward; Hildenbrand, Philipp; Gerstein, Gregory; Rodman, Dmytro; Nuernberger, Florian; Merklein, Marion; Maier, Hans Juergen (Journal of Materials Engineering and Performance, 2016)
To produce parts from sheet metal with thickened functional elements, bulk forming operations can be employed. For this new process class, the term sheet-bulk metal forming has been established recently. Since sheet-bulk metal forming processes such as orbital forming generates triaxial stress and strain states, ductile damage is induced in the form of voids in the microstructure. Typical parts will experience cyclic loads during service, and thus, the influence of ductile damage on the fatigue life of parts manufactured by orbital forming is of interest. Both the formation and growth of voids were characterized following this forming process and then compared to the as-received condition of the ferritic deep drawing steel DC04 chosen for this study. Subsequent to the forming operation, the specimens were fatigued and the evolution of ductile damage and the rearrangement of the dislocation networks occurring during cyclic loading were determined. It was shown, that despite an increased ductile damage due to the forming process, the induced strain hardening has a positive effect on the fatigue life of the material. However, by analyzing the fatigued specimens a development of the ductile damage by an increasing number of voids and a change in the void shape were detected.
LFT Import::2019-07-29 (2149)
Keywords: DC04; ductile damage; orbital forming; sheet-bulk metal forming

Durchgängiger Einsatz der Simulationstechnik - Christoph, F.; Collisi, T.; Kohlbauer, Rainer; Völkl, Ralf; Effert, C.; Oertli, T.; Siggenauer, T. (VDI-Z Integrierte Produktion, 2002)
LFT Import::2019-07-16 (1667)

Düsenbasiertes Laserstrahl-Löten mit Formteilen zur hochtemperaturfesten Kontaktierung piezokeramischer Substrate - Stein, Stefan; Heberle, Johannes; Hugger, Florian; Roth, Stephan; Schmidt, Michael (Tagungsband des 17. Seminars Laser in der Elektronikproduktion und Feinwerktechnik, 2014)
Piezokeramiken bieten aufgrund ihrer Eigenschaften vielseitige Anwendungsmöglichkeiten. Werden sie beispielsweise in Sturkturbauteile integriert, so kann über eine frequenzmodulierte Ansteuerung eine aktive Schwingungsdämpfung realisiert werden. Die Integration von Piezoaktoren in Strukturbauteile stellt jedoch in der Großserienfertigung aufgrund der Komplexität der Verarbeitung und Kontaktierung bisher ein ungelöstes Problem dar. Aufgrund der hohen Anforderungen an die Kontaktierung wird am Bayerischen Laserzentrum das Laser Droplet Brazing entwickelt, welches sich durch eine sehr definierte Energieeinbringung in die Fügestelle auszeichnet. Es wird hierbei eine Hartlotkugel in eine Kapillare eingebracht, dort mittels eines Laserpulses aufgeschmolzen und durch einen, in der Kapillare herrschenden, Überdruck ausgestoßen. Die schmelzflüssige Lotkugel fällt auf ein sich unter der Düse befindliches Kontaktpad und benetzt dort sowohl die Metallisierung des Substrates als auch den Kupferdraht. Im Anschluss erstarrt die Lotkugel, wodurch es zu einer stoffschlüssigen Kontaktierung von Substrat und Kupferdraht kommt. Mit dem Laser-Droplet-Brazing-Verfahren lassen sich thermisch stabile Hartlötverbindungen auf wenigen µm starken Metallisierungen realisieren, wobei eine thermische Schädigung des Substrates aufgrund der definierten Energiedeposition vermieden werden kann. Es eignet sich somit sowohl für die Kontaktierung von Piezokeramiken als auch für andere Aufgabenstellungen, bei denen hochtemperaturstabile Kontaktierungen auf dünnen Metallisierungen erzeugt werden müssen, ohne das Substrat thermisch zu schädigen. Das Verfahren sowie die System- und Prozesstechnik werden im vorliegenden Artikel vorgestellt. Daneben werden die Einflüsse von Prozessparametern wie Pulsdauer und Pulsleistung auf das Kontaktierungsergebnis aufgezeigt und Kontaktierungsergebnisse diskutiert, sowie deren Anbindung metallografisch und durch Schertests untersucht.
Keywords: Laserstrahllöten; Hartlöten; Piezokeramik; Kontaktierung; Laser Droplet Brazing

Dynamic correction of oscillatory forces during ultrasonic-assisted metal forming - Michalski, Markus; Leicht, Uwe; Heath, Andrew; Merklein, Marion (Production Engineering, 2017)
Numerous investigations in the past decades reported that the forces required for forming processes can be reduced by superimposing high frequency oscillation. Even though many studies have been carried out identifying and assessing the complex cause of this reduction, cause-effect relationships are generally not yet established in detail. Since the measurement of dynamic forces plays a key role in clarifying the causes, a precise measurement of the forming forces oscillating with high frequency is necessary. Although dynamic force measurement is a well-known field of research, this study focuses on its utilisation for ultrasonic-assisted forming processes. Since dynamic effects distort original measurements in this frequency range, adjustment is required. Based on measurement instruments with high temporal resolution the present study introduces an approach for creating and employing a frequency dependent force correction in the high dynamic range. The experimental procedure for creating a transfer function up to a limiting frequency of 40 kHz is later analysed and verified by numerical modal and transient simulations. The results indicate that the highly location dependent dynamic force detection has major influence on peak forces. Observed deviations can be precisely corrected using the generated frequency dependent transfer function.
LFT Import::2019-07-29 (2239)
Keywords: Finite element method (FEM); Force; Measurement; Metal forming; Transfer function; Ultrasonic

Eddy Current Measurement of Mechanical Properties of Sheet Metal - Geiger, Manfred; Schwind, Michael; Engel, Ulf (Production Engineering, 1995)
LFT Import::2019-07-15 (555)

Edge crack sensitivity of lightweight materials under different load conditions - Tsoupis, Ioannis; Merklein, Marion (IOP Conference Series: Materials Science and Engineering, 2016)
This study addresses the analysis of edge crack sensitivity of DP800 steel and AA5182 aluminum alloy in dependency of punching and machining operation as well as load case of subsequent forming. The inserting of a round hole by punching with defined punch-to- die-clearance, milling and drilling is compared. Subsequent forming is performed by standardized hole expansion test and by Nakajima-tests with three different specimen geometries. Local strain distribution at the surface for Nakajima-tests is measured by optical strain measurement technique and investigated in order to evaluate local deformation before failure. Additionally, resulting hole expansion ratio λ is determined. Significant higher X as well as local strain values ϵ max are achieved by machined holes. This is directly coupled to higher local formability and stretchability for both materials. Furthermore, the load condition has a strong impact on the edge crack sensitivity of the material. Prior failure is observed with changing stress conditions using different specimen geometries also influencing the reachable maximum failure strain. Higher edge crack sensitivity is observed for DP800, which is in good accordance to the material properties in terms of ductility and strength. These data in dependency of the process parameter can be used for the design of automotive components.
LFT Import::2019-07-29 (2172)

Editors' Choice-Respirometric in Situ Methods for Real-Time Monitoring of Corrosion Rates: Part I. Atmospheric Corrosion - Strebl, Michael; Bruns, Mark; Virtanen, Sannakaisa (Journal of The Electrochemical Society, 2020)
A novel respirometric approach to monitor atmospheric corrosion kinetics is presented. Simultaneous real-time monitoring of the H-2 evolution reaction (HER) and the O-2 reduction reaction (ORR) is possible with a combination of optical O2 sensor measurements with gravimetric volume sensitive techniques or pressure sensor based techniques in closed chambers. The respirometric method is a universal, non-destructive tool applicable to any metal or alloy. It shows a high sensitivity for low corrosion rates and has a high time-resolution. Different examples of relevant engineering metals and alloys will be provided. Mass loss validation measurements carried out at the end of exposure show a good correlation with the total recorded cathodic charge. For metals with different oxidation states the average valency in the corrosion products can be calculated from the cathodic charge together with mass loss. The versatility of the novel monitoring technique is further demonstrated by studying the influence of wet-dry cycling, temperature steps or changes in the gas composition in situ. The rate of HER, ORR and total corrosion rate during these changing exposure conditions can be tracked directly on the same sample. Overall the new method contributes to bridging the gap between lab tests, accelerated testing and field exposure. (C) 2020 The Author(s). Published on behalf of The Electrochemical Society by IOP Publishing Limited.
CRIS-Team WoS Importer:2020-03-13

Effective Stochastic Simulation for the Optimization of Time, Costs and Quality in Cold Forging - Koch, Johannes Peter Karl; Völkl, Ralf; Engel, Ulf (International Journal of Material Forming, 2008)
In cold forging tool life is limited in most cases by fatigue and characterized by distinct scatter depending on the scatter of the process parameters. This fact is also obstructing the production of net shape parts. Due to the scatter, a single simulation run with average values is known to be not appropriate to predict the desired output quantities. This paper describes an innovative method using a mathematical model of the forging process with a deterministic and a statistical component. According to the strength versus load concept (SVL-concept), a combination of the parametric and the statistical model leads to an integrated statistical process model which enables tool life prediction by taking statistical effects into account. In order to improve tool life an approach of avoiding tensile stresses and strains in the die has been successfully used for steel and cemented carbide tools. © Springer/ESAFORM 2008.
LFT Import::2019-07-29 (329)
Keywords: Cold Forging; Computer Aided Engineering; Stochastic Simulation; Tool Life

Effect of a Local Laser Heat Treatment on the Formability of Multi-layered 6000 Series Aluminum Alloys - Merklein, Marion; Herrmann, Jürgen (Physics Procedia, 2016)
The production of multi-layered aluminum alloys using the Accumulative Roll Bonding Process (ARB) is an auspicious possibility to fabricate nanostructured sheet material with enhanced mechanical properties. The increased strength qualifies these semi-finished products for lightweight applications in automotive industry. However, the ARB process also leads to a reduced ductility of the ultra-fine grained material. Furthermore, failure mechanisms like delamination can occur during forming operations. A local short term laser heat treatment according to the Tailor Heat Treated Blanks technology can be applied in order to enhance the formability and prevent failure. Multi-layered sheets of the aluminum alloy AA6014 were produced in a warm rolling process. The mechanical properties as well as the bond strength are investigated within this contribution using tensile tests and T-peel tests. The material characterization is carried out in dependency of the heat treatment temperature. Air bending tests in combination with a local laser heat treatment are used in order to investigate the formability of the multi-layered aluminum sheets.
EAM Import::2019-03-14

Effect of a strain rate dependent material modeling of a steel on the prediction accuracy of a numerical deep drawing process - Vallaster, Eva; Wiesenmayer, Sebastian; Merklein, Marion (Production Engineering, 2023)
In the production of sheet metal components, batch and process fluctuations cause deviations in the resulting component properties, which often lead to production rejects. To counteract this inline, the computing time for predicting the process result and optimizing the process parameters must be very short, which is why analytical models are advantageous. A large database is usually required for modeling, and numerical simulations are well suited for generating it. The stamping velocity is a process parameter possibly varying, but strain rate dependency of the material often is neglected in numerical simulations. The objective of this study is to analyze the effects of strain rate dependent material modeling on the simulation accuracy of a sheet metal forming process. Therefore, uniaxial tensile tests and layer compression tests at different strain rates are conducted on the steel HC340LA. Based on this, the material behavior is captured in a strain rate dependent material card, which is used for the numerical simulation of a deep drawing process of a geometry with complex shape. For the validation of the model, experiments are carried out and being compared with the computational results in terms of force–displacement curves and part geometry. Furthermore, numerical investigations are used to analyze if drawbead height and blankholder force have an influence on the strain rate distribution and whether this affects the process forc

Effect of elevated tool temperatures on the properties of high-strength aluminum alloys during tailor quench forming (TQF) - Rigas, Nikolaos; Jäckisch, Manuel; Merklein, Marion (Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture, 2022)
High-strength aluminum alloys have a great lightweight potential due to their high specific strength-to-weight ratio. However, industrial use of this material is limited due to the low formability at room temperature. In recent years, the so-called hot forming quench (HFQ®) process has proven, to be an effective forming method for manufacturing high-strength aluminum alloys. During deep drawing, the high cooling rate generates the potential for a subsequent aging operation and thereby the formation of strength-increasing precipitations. As a result, complex-shaped components with high strength can be produced. In the future, tailored components with both ductile and high-strength areas are increasingly needed to fulfill the growing lightweight and safety requirements of the government. One method to influence the mechanical properties is the use of a tailor quench forming (TQF) process. In this regard, a simultaneous component production and adjustment of the final mechanical properties is possible. However, it has not been investigated so far, how the tool temperature and the subsequent aging parameters influence the thermal interactions and thus the mechanical characteristics of the parts. In addition, the crash performance of these components has not been investigated. For this reason, a high-strength aluminum alloy is quenched under different thermal conditions and is then artificially aged. To determine the resulting thermo-mechanical properties, temperature analysis, hardness tests and tensile tests, as well as high-speed tests have been performe
Keywords: AA7075; Tailor quench forming; Mechanical properties; Crash performance

Effect of laser beam alloying strategies on the metallurgical and mechanical properties of hot forming tool steels - Hofmann, Konstantin; Neubauer, Franziska; Holzer, Matthias; Mann, Vincent; Hugger, Florian; Roth, Stephan; Schmidt, Michael (LANE 2016 - 9. International Conference on Photonic Technologies, 2016)
In terms of increasing lightweight designs of car body parts, the machining of high strength steels in hot stamping processes becomes of particular interest. Due to high process forces at hot stamping, the surface of such tools in the area of maximal stress is subject wear, which necessitate some local increase of microhardness to enhance the mechanical performance. Especially laser beam alloying using filler wire and beam oscillation is some suitable method to modify the mechanical properties of tool surfaces to emcompass some continuous martensitic structure, featuring a certain microhardness. Nevertheless the thermal energy input during laser beam alloying induces tempering in the heat affected zone and reduces the hardness. This paper discusses the influence of alloying strategies on the thermal energy input and the resulting metallurgical structure of modified tool surfaces. Also the cooling behavior of alloyed lines for different energy inputs per unit length is of interest. Therefore, the metallurgical microstructure is analyzed regarding microhardness as well as formation of carbides. Furthermore, a numerical thermal simulation is developed to investigate the temperature profile in the heat affected zone of the specimen. These investigations permit the control of the spatiotemporal energy input to avoid tempering of the microstructure.
LFT Import::2019-08-05 (2251)
Keywords: Adhesive and abrasiv wear; filler wire; hot forming steels; laser beam alloying

Effect of picosecond laser based modifications of amorphous carbon coatings on lubricant-free tribological systems - Häfner, Tom; Heberle, Johannes; Hautmann, Hubert; Zhao, Rong; Tenner, Jennifer; Tremmel, Stephan; Merklein, Marion; Schmidt, Michael (Journal of Laser Micro Nanoengineering, 2017)

Effect of process conditions on mechanical behavior of aluminium wrought alloy EN AW-2618 additively manufactured by Laser Beam Melting in powder bed - Karg, Michael; Ahuja, Bhrigu; Schaub, Adam; Schmidt, Jochen; Sachs, Marius; Mahr, Alexander; Wiesenmayer, Sebastian; Wigner, Leon; Wirth, Karl-Ernst; Peukert, Wolfgang; Merklein, Marion; Schmidt, Michael (Proceedings of Laser in Manfacturing Conference 2015, 2015)
Additive Manufacturing offers geometric freedom excellently suited for topology optimized light weight designs. Ideally these should be built from materials of high strength to weight ratio and high plastic formability- such as aluminium-copper wrought alloys. Al-Cu wrought alloys are considered much less suitable for welding without cracks, so processing them in Laser Beam Melting of Metals in powder bed (LBM) can be considered challenging. Today, the only class of aluminium alloys widely processed by LBM is that of aluminium-silicon cast alloys which are easily weldable. In this contribution, mechanical characteristics of LBM samples are presented and discussed. Tensile tests were conducted under variation of load direction relative to build-up direction and heat treatment. Pronounced anisotropy was observed. Remarkably, elongation at break of T6 heat treated samples pulled in build-up direction exceeds values from literature for conventionally manufactured EN AW-2618A. The chemical constitutions of both the powder and the LBM samples were analyzed and shown to be similar to the expected EN AW-2618A. For further interpretation, boundary conditions of sample production, metallographic microsections and fracture surfaces were considere
Keywords: Additive Manufacturing; high-strength Aluminium Copper Wrought Alloy EN AW-2618A; AlCuMgNi; 3.1924; Selective Laser Melting™; LaserCUSING™; Direct Metal-Laser-Sintering™

Effect of Residual Stress on the Distortion of Microembossed Metal Inserts for Assembly Injection Moulding - Frey, Philipp; Höhler, C.; Merklein, Marion (4M/IWMF2016 Conference: Proceedings of 11th International Conference on Multi-Material Micro Manufacture, 2016)
LFT Import::2019-08-05 (2214)

Effect of Surface Structure on Run-in Wear in Steel-Polyamide Gear Sets - Schubert, Dominik; Rohrmoser, Andreas; Merklein, Marion; Drummer, Dietmar (Zeitschrift Kunststofftechnik, 2019)

Effect of temperature and punch speed on forming limit strains of AA5182 alloy in warm forming and improvement in failure prediction in finite element analysis - Satish, D. Raja; Kumar, D. Ravi; Merklein, Marion (Journal of Strain Analysis For Engineering Design, 2017)
Formability of AA5182-O aluminum alloy sheets in the warm working temperature range has been studied. Forming limit strains of sheets of two different thicknesses have been determined experimentally in different modes of deformation (biaxial tension, plane strain and tension-compression) by varying temperature and punch speed. A correlation has been established for plane strain intercept of the forming limit diagram (FLD0) with temperature, punch speed and thickness from the experimental results. This correlation has been used to plot the forming limit diagrams for failure prediction in the finite element analysis of warm deep drawing of cylindrical cups. The effect of strain and strain rate on material flow behavior has been incorporated using a strain rate-sensitive power hardening law in which the strain hardening exponent and strain rate sensitivity index have been experimentally determined. The predictions from simulations have been validated by warm deep drawing experiments. Large improvement in accuracy of failure prediction has been observed using the FLDs plotted based on the developed correlation when compared to the existing method of calculating FLD0 using only strain hardening coefficient and thickness. The results clearly indicate the importance of incorporating temperature and punch speed in failure prediction of Al alloys using FLDs in the warm working temperature range.
CRIS-Team Scopus Importer:2023-03-29
Keywords: aluminum alloy; failure prediction; finite element simulation; forming limit diagram; warm deep drawing; Warm forming

Effect of the welding gap on heat flow welding - Komlodi, Attila (Proceedings of microCAD 2000, International Computer Science Conference, University of Miskolc, 2000)
LFT Import::2019-08-05 (817)

Effect on the mechanical properties of sheet metals after the use of drawbeads in deep drawing - Schmid, Harald; Merklein, Marion (5th International Conference on New Forming Technology ICNFT Bremen 2018, 2018)
The use of modern and more complex materials leads to a need for detailed knowledge and controlling of the material flow. Next to the blank holder force or the lubrication system, drawbeads are nowadays one common way to bring serial forming processes under control. Although drawbeads are already well investigated regarding their retention forces, the effect on the resulting mechanical properties after a drawbead passage is not analysed in detail yet. This work will show the influence of a common drawbead geometry used in forming processes on typical mechanical properties of sheet metal. Therefore, two different sheet metal materials are preloaded in a modified strip drawing test with industrial used drawbead geometry. In testing, three different pressure levels between 2.5 MPa and 7.5 MPa and three levels of drawing speed between 10 mm/s and 50 mm/s are combined to nine variations which will be examined. Afterwards, specimens are cut out by a laser cutting machine of the drawn strips. Those already preloaded and deformed specimens are then tested under standard conditions with the use of an optical measurement system. The results like tensile strength or elongation at fracture are compared to the initial state and each other and discussed with consideration of pressure and speed levels to work out the main effects. Those results are a contribution for the optimization of deep drawing simulations of parts including drawbeads or to evaluate the influence of drawbeads on forming processes to specify or even expand process limitations.
LFT Import::2019-08-05 (2317)
Keywords: Deep drawing; Hardening; Sheet metal

Effects of PVD and CVD Coatings on Fatigue Strength of Tool Steel for Cold Forging - Geiger, Manfred; Engel, Ulf; Hinsel, Christian (Production Engineering, 1998)
LFT Import::2019-07-16 (1586)

Effects of specimen size and geo-metry in metal forming. - Kals, Roland; Pucher, Hans-Jörg; Vollertsen, Frank; Geiger, Manfred (Proc. of the 2nd int. conf. on advances in materials and processing technologies, 1995)
LFT Import::2019-08-05 (569)

Effects of viscous dissipation in flow-inflluenced tube hydroforming - Dal Bò, Paolo; Geiger, Manfred (International Journal of Microstructure and Materials Properties, 2008)
LFT Import::2019-07-29 (1508)

Effects of viscous dissipation in the flow influenced tube hydroforming - Dal Bò, Paolo; Geiger, Manfred (International Journal of Microstructure and Materials Properties, 2006)
LFT Import::2019-07-16 (1345)

Efficient Aluminium - Anwendung hochfester Aluminiumlegierungen im modernen Karosseriebau - Degner, Julia; Merklein, Marion (Tagungsband des 37. EFB-Kolloquiums Blechverarbeitung 2017, 2017)
LFT Import::2019-08-05 (2223)

Efficient Aluminum - Qualifizierung des Einsatzes höchstfester Aluminiumlegierungen im Karosseriebau - Lechner, Michael; Zimmermann, Andrea; Graser, Matthias; Merklein, Marion (Tagungsband zum 1. Green Factory Bavaria Kolloquium 2014 - Engergieeffiziente Produktion, 2014)
LFT Import::2019-08-05 (2044)

Effiziente Bewertung von Blechumformprozessen durch die Reduzierung kritischer Einflussgrößen in der stochastischen Simulation - Merklein, Marion; Sturm, Vera; Wahl, M. (Bauteile der Zukunft - Methoden und Prozesse - Tagungsband T31 des 30. EFB-Kolloquiums Blechverarbeitung am 2. und 3. März 2010 in Bad Boll, 2010)
LFT Import::2019-08-05 (311)

Effiziente maßgeschneiderte Wärmebehandlung von Blechhalbzeugen in der Serienfertigung - Kahrimanidis, A.; Lechner, Michael; Wortberg, D.; Merklein, Marion (wt Werkstattstechnik - Online, 2015)
By using aluminium alloys in the automotive industry, the mass of cars can be reduced and their environmental compatibility increased. However, the formability of aluminium alloy is limited in comparison to conventional steel material. Therefore, the Institute of Manufacturing Technology has cooperated with the Daimler AG to develop a new approach for enhancing formability by local heat treatment before the forming operation. The technology is known as Tailor Heat Treated Blanks (THTB). This paper presents the efficient integration of the approach in the press shop with respect to technological restrictions. Also, the suitability of different heat treatment methods in dependency of production quantity and the number of variants will be discussed and a recommendation is derived.
CRIS-Team Scopus Importer:2024-02-29

Effiziente maßgeschneiderte Wärmebehandlung von Blechhalbzeugen in der Serienfertigung - Kahrimanidis, Alexander; Lechner, Michael; Wortberg, D.; Merklein, Marion (wt Werkstattstechnik - Online, 2015)
LFT Import::2019-07-29 (2119)

Effiziente Prozesskettenauslegung für das Umformen lokal wärmebehandelter und geschweißter Aluminiumbleche - Staud, Detlev (Friedrich-Alexander-Universität Erlangen-Nürnberg, 2010)
The scope of this work was the generation of basic principles to the efficient forming process design of local heat treated and welded aluminum sheet metal. The main process characteristic is a selective heat treatment to adapt the mechanical properties of unwelded or welded aluminum sheets for the subsequent forming process. The fundamental objective of the dissertation was the development of a simulation based process design by means of an inverse procedural method. In contrast to an ordinary approach the heat treatment layout is already determined within the forming step. Thus a robust forming process is generated before the heat treatment parameters are defined. The benefits of this inverse approach are less extensive simulations loops of both forming and heat treatment calculations. Supported are these investigations by means of relevant material properties and the continuous validation of the heat treatment and the forming proces

Eigenschaften reibrührgeschweißter Aluminium-Stahl-Verbindungen - Geiger, Manfred; Merklein, Marion; Giera, Artur; Staud, Detlev (Berichtskolloquium der DFG-Forschergruppe 505, 2005)
LFT Import::2019-08-05 (1242)

Eigenspannungen beim Voll-Vorwärts-Fließpressen – Entstehung, Einstellung und Stabilität - Jobst, Andreas (Friedrich-Alexander-Universität Erlangen-Nürnberg, 2024)
Kaltmassivumformverfahren wie das Voll-Vorwärts-Fließpressen werden als ressourcen- und energieeffiziente Fertigungsmethode für metallische Bauteile eingesetzt. Inhomogene plastische Dehnungsverteilungen, die dabei typischerweise auftreten, führen jedoch zum Verbleiben von Eigenspannungen im Werkstoff, welche zu unerwünschten Effekten führen und das Ermüdungsverhalten maßgeblich beeinflussen können. Das in dieser Arbeit verfolgte Ziel ist die Erarbeitung einer Methode zur eigenspannungssensitiven Prozessauslegung. Anhand eines Referenzprozesses wurde die Eigenspannungsentstehung beim Voll-Vorwärts-Fließpressen des rostfreien Stahls X6Cr17 numerisch und experimentell untersucht. Darauf aufbauend wurden Steuer- und Störgrößen zur Eigenspannungseinstellung qualifiziert und deren Auswirkungen quantifiziert. Unter zyklisch-mechanischer Bauteilbelastung wurden verschiedene Relaxationsmuster identifiziert. Hinsichtlich der thermischen Belastung wurde ein Prozessfenster erarbeitet, innerhalb dessen stabile Eigenspannungen vorliegen. Darauf aufbauend wurde ein modellbasierter Zusammenhang zwischen der Temperatur, der Belastungsdauer und der Eigenspannungsstabilität abgeleitet. Es konnte gezeigt werden, dass eine Beeinflussung der Betriebsfestigkeit fließgepresster Bauteile durch die Eigenspannungssteuerung bei der Umformung möglich ist. Durch eine Anpassung des Matrizendesigns konnten kostengünstig oberflächennahe Zugeigenspannungen reduziert und die Langzeitfestigkeit erhöht werd

Ein Ansatz zur Herstellung von pressgehärteten Karosseriekomponenten mit maßgeschneiderten mechanischen Eigenschaften: Temperierte Umformwerkzeuge. Prozessfenster, Prozesssimulation und funktionale Untersuchung - Feuser, Peter (Friedrich-Alexander-Universität Erlangen-Nürnberg, 2012)
During this study, the manufacturing technology partial press-hardening with heated forming tools was investigated in detail. The central goal was to develop a fundamental understanding of the manufacturing process window, and to illustrate approaches for simulation-based tool and process design. In addition to investigating the process on the basis of simplified experiments, the focus always lay on the knowledge-transfer to the real manufacturing proces

Ein Beitrag zur digitalen Auslegung von Fügeprozessen im Karosseriebau mit Fokus auf das Remote-Laserstrahlschweißen unter Einsatz flexibler Spanntechnik - Bauer, Felix (Friedrich-Alexander-Universität Erlangen-Nürnberg, 2022)
The use of pneumatically actuated clamping rolls attached to welding robots enables an increase in flexibility in remote laser welding in the Body in White shop. The design of the clamping forces, the joining devices and the component tolerances suitable for production represent a challenge. In this work, the clamping and joining process of remote laser welding with a clamping roll was investigated. The investigation was carried out by experiments and simulations with sheet metal parts made of steel and aluminum, as well as for cast aluminum components. For the simulative investigation, validated finite element simulation models were developed, which represent the use of a flexible clamping roll in the Body in White shop for the first time. The simulation models enable the calculation of clamping processes in three ways: displacement-controlled with complete specification of the roll movement, force-controlled with specification of the clamping force progress and force-regulated with specification of the desired resultant joint gaps. Based on the investigations, process- and component-related solutions for reducing the required clamping forces and the resultant joint gaps were identified and a fundamental process understanding for the novel manufacturing process was develope

Eine Simulationsmethode für das 3-Rollen-Schubbiegen - Vipavc, Daniel (Friedrich-Alexander-Universität Erlangen-Nürnberg, 2019)
Die komplexgebogenen Bauteile werden aufgrund der benötigten Prozess-flexibilität immer öfter durch kinematische Freiformbiegeprozesse umgeformt. Das Freiformbiegen ist aber aufgrund des mangelhaften Prozessverständnisses in hohem Maße ungenau und für industriele Applikation zu langsam. Die in dieser Arbeit entwickelte Methodik stellt einen wichtigen Beitrag zur Umsetzung einer allgemeingültigen Prozessauslegungsstrategie für die Realisierung eines auf dem Rollen-Schubbiegen basierenden Freiformbiegen. Für zeiteffiziente und genaue Ermittlung der Prozessparameter wurde ein neuartiges numerisches Modell vorgestellt, wobei die Modellierung des Einflusses der Maschinenstruktur auf das Biegeergebnis eine besonders wichtige Rolle spielt. Zur Gewährleistung einer hohen Berechnungsgenauigkeit wurden insbesondere genau die elastischen Deformationen der Maschinenstruktur untersucht und in das Modell implementiert. Schließlich wurde das Modell optimiert und mit experimentell gewonnenen Daten validier

Einfluss anisotropen Materialverhaltens von Aluminium-Glänzwerkstoffen auf die Rissausbildung beim Lochaufweitversuch - Beck, Johannes; Merklein, Marion; Friedrichsen, M. (Tagung Werkstoffprüfung 2016, 2016)
LFT Import::2019-08-05 (2198)

Einfluss der Auflösung des Dehnungsfeldes auf die Kennwertermittlung im Scherzugversuch von Aluminium- und Magnesiumlegierungen - Lenzen, Matthias; Suttner, Sebastian; Merklein, Marion (Tagung Werkstoffprüfung 2016, 2016)
LFT Import::2019-08-05 (2194)

Einfluss der Auswertestrategie auf die Grenzformänderungskurve - Kuppert, Andreas; Friebe, H.; Hotz, W.; Merklein, Marion; Möller, T.; Volk, W. (Tagungsband Werkstoffprüfung 2012, 2012)
LFT Import::2019-08-05 (1850)

Einfluss der Auswertestrategie auf die Grenzformänderungskurve - Kuppert, Andreas; Merklein, Marion; Friebe, H.; Möller, T.; Hotz, W.; Volk, W. (MP Materials Testing, 2013)
LFT Import::2019-07-29 (1914)

Einfluss der fertigungsbedingten Gestalt und Struktur auf das Einlaufverhalten von Stahl-Kunststoff-Getriebepaarungen - Schubert, Dominik; Rohrmoser, Andreas; Hagenah, Hinnerk; Merklein, Marion; Drummer, Dietmar (Industriekolloquium der Forschergruppe FOR 2271, 2019)

Einfluss der Fließkurve auf den Rohrbiegeradius - Merklein, Marion; Vatter, Peter; Plettke, Raoul; Grüner, Martin (wt Werkstattstechnik - Online, 2012)
LFT Import::2019-07-29 (1816)

Einfluss der Oberflächenbeschaffenheit auf das Werkzeugeinsatzverhalten beim Kaltfließpressen - Andreas, Kolja (Friedrich-Alexander-Universität Erlangen-Nürnberg, 2015)
The thesis investigated the interdependencies between tool machining, surface integrity and the resulting behavior of cold forging tools. In laboratory tests a distinct influence of the tool surface on the frictional and fatigue behavior could be detected. Serial production tests proved the usability of the gained functional correlations for an increase of tool lif

Einfluss der Werkzeugeigenschaften auf die tribologischen Bedingungen beim Presshärten - Schwingenschlögl, Patrik; Merklein, Marion (XXXVII. Verformungskundliches Kolloquium, 2018)
LFT Import::2019-08-05 (2311)

Einfluss der Werkzeugtemperatur auf die tribologischen Bedingungen beim Presshärten - Schwingenschlögl, Patrik; Tenner, Jennifer; Gauglitz, S.; Merklein, Marion (11. Erlanger Workshop Warmblechumformung, 2016)
LFT Import::2019-08-05 (2217)

Einfluss des Schmierstoffs auf die Werkstückqualität in der Blechmassivumformung - Löffler, Maria; Andreas, Kolja (Tagungsband XXXV. Verformungskundliches Kolloquium, 2016)
LFT Import::2019-08-05 (2160)

Einfluss des Vormaterials auf die mehrstufige Kaltumformung vom Draht - Zimmermann, Bastian (Friedrich-Alexander-Universität Erlangen-Nürnberg, 2022)
In the production of fasteners, wire materials are usually used as prematerial. Due to the strong cost pressure in a globalized sales market, the pre-material as a potential factor for reducing manufacturing costs moves into focus. However, an incorrect choice of pre-material carries the risk of impairing process capability, as can be seen from the model process investigated in this work. A detailed analysis of a boron-manganese steel made it possible to determine how the wire manufacturing process affects the plastic material properties. The developed modeling approaches which take into account the properties from preliminary processes in numerical models now allow the quantification of properties of different manufacturing variants of a wire material. In addition, an investigation of important basic forming operations shows that the targeted use of prematerial conditions can also be used to extend process limit

Einfluss des Werkstoffes auf die wirkmedienbasierte Belchumformung - Celeghini, Martino (Tagungsband zum XXIII. Verformkundlichen Kolloquium, Planneralm, 29.02.-06.03.2004. Leoben, 2004)
LFT Import::2019-08-05 (1037)

Einfluss erhöhter Prozesstemperatur auf die Formänderungsgrenzen beim Mikrofließpressen - Eichenhüller, Bernd; Egerer, Emil; Engel, Ulf (Erweiterung der Formgebungsgrenzen bei Umformprozessen. Abschlussbericht DFG Schwerpunkt, 2005)
LFT Import::2019-08-05 (1169)

Einflussgrößen im Presshärtprozess - Merklein, Marion; Hoff, Cornelia; Lechler, Jürgen (Car Body Colloquium, 2005)
LFT Import::2019-08-05 (1202)

Einfluss mikrogeformter Kanten an Metalleinlegern auf die Temperaturwechselbeständigkeit mediendichter Kunststoff-Metall-Hybriden - Heinle, Martina; Frey, Philipp; Merklein, Marion; Drummer, Dietmar (Zeitschrift Kunststofftechnik, 2018)
The increasing number of electronics in several industrial sectors leads to a rising demand for flexible and adaptable electronic systems with high functional density and resilience. An efficient method for producing such parts is the encapsulation of metal inserts, for example lead frames, by means of assembly injection molding. Here one major challenge is to provide electronics with durable media tightness in a severe environment. The research work covered in this paper focuses on the influence of micro formed edges of metal inserts on the durability of tightness during temperature cycling.
LFT Import::2019-07-29 (2339)
Keywords: Assembly injection molding; Edge rounding; Embossing; Polymer-metal-hybrids; Temperature-shock-test; Tightness

Einflussparameter beim Laserstrahlbiegen metallischer Folien - Meyer-Pittroff, Frank; Otto, Andreas (Laser in der Elektronikproduktion & Feinwerktechnik, 2000)
LFT Import::2019-07-15 (791)

Einfluss thermomechanischer Prozessparameter auf die tribologischen Eigenschaften beim Presshärten - Wieland, Michael; Merklein, Marion (8. Erlanger Workshop Warmblechumformung, 2013)
LFT Import::2019-08-05 (1922)

Einfluß unterschiedlicher Wärmebehandlungsrouten auf die Robustheit und Höhe der mechanischen Eigenschaften des Stahls 22MnB5 - Glatzer, M.; Stöhr, Thomas; Merklein, Marion; Sikora, S. (Tagungsband 4. Erlanger Workshop Warmblechumformung, 2009)
LFT Import::2019-08-05 (218)

Einfluss von Chargenschwankungen auf die Verarbeitungsgrenzen von Stahlwerkstoffen - Sturm, Vera (Friedrich-Alexander-Universität Erlangen-Nürnberg, 2013)
Due to the increasing complexity of car body components, the process window of the forming process without defects is limited. Consequently, in serial production process even small variations of material properties may lead to rejections as a result of defects. Within this book a methodology is presented, capable of detecting the impact of significant varying material properties on the forming result in an efficient manner. As a result it shall be possible to design a robust process even at the time of process layou

Einfluß von Strahleigenschaften auf die Bearbeitungsqualität beim Schneiden mit dem Laser - Biermann, Stefan; Nuss, Rudolf; Geiger, Manfred (Maschinenmarkt, 1988)
LFT Import::2019-07-15 (270)

Einformung der Oberflächenstruktur in umformtechnischen Prozessen - Pfestorf, Markus; Engel, Ulf (Reibung und Verschleiß, 1996)
None
LFT Import::2019-08-05 (1986)

Einführung neuer Produktions- und Schlüsseltechnologien am Beispiel der Laserstrahlbearbeitung. Schnell lernende Unternehmen - Quantensprünge in der Wettbewerbsfähigkeit - Geiger, Manfred; Hutfless, Joachim (Tagungsband Münchner Management Kolloquium, 1995)
LFT Import::2019-08-05 (546)

Einglättung strukturierter Oberflächen - Neudecker, Thomas; Pfestorf, Markus; Engel, Ulf (Tribologie und Schmierungstechnik, 1997)
LFT Import::2019-07-11 (677)

Einglättung strukturierter Oberflächen unter Druckbelastung mit und ohne Schmierstoffeinsatz. - Neudecker, Thomas (8. Deutschsprachiges ABAQUS-Anwender-Treffen., 1996)
LFT Import::2019-08-05 (675)

Einsatz der numerischen Prozeßsimulation in der Werkzeugentwicklung - Falk, Bernd; Engel, Ulf; Geiger, Manfred (Zeitschrift für wirtschaftlichen Fabrikbetrieb, 1999)
LFT Import::2019-07-16 (2004)

Einsatz des Hochleistungswerkstoffes Hartmetall in der Umformtechnik - Hartmetall als Werkzeugwerkstoff - Andreas, Kolja (Konstruktion, 2015)
LFT Import::2019-07-29 (2105)

Einsatz numerischer Analysetools bei der Auslegung und Herstellung kaltfließgepresster Stahlzahnräder - Rohrmoser, Andreas; Kiener, Christoph; Hagenah, Hinnerk; Merklein, Marion (Konstruktion, 2019)
In the drivetrain and transmission technology gears are used in large quantities, which is why an efficient and sustainable production is gaining importance. At the same time the application of new material combinations leads to a demand for adjustable component properties in order to positively influence the operational behavior. Cold forging provides the potential of manufacturing geared components with beneficial mechanical and geometrical properties in a highly productive process. However the industrial application of cold forging faces challenges regarding limited tool life and the achievable gear quality. To face these challenges the development of targeted approaches within the component and process design is necessary. In this context the application of numerical analyses offers a promising approach, which enables the investigation of the resulting operational behavior of the forming tool and gear.
LFT Import::2019-07-29 (2372)

Einsatz prozessangepasster Aluminiumplatinen für die Herstellung von Karosserieziehteilen - Merklein, Marion; Vogt, Uwe (Arbeits- und Ergebnisbericht des DFG SFB 396, 2007)
LFT Import::2019-08-05 (1472)

Einsatz prozessangepasster Aluminiumplatinen in der Blechumformung - Merklein, Marion; Kerausch, Michael (Viertes Industriekolloquium, SFB 362 Fertigen in Feinblech, Multi-Material-Design, 2004)
LFT Import::2019-08-05 (1056)

Einsatz technologischer Versuche zur Erweiterung der Versagensvorhersage bei Karosseriebauteilen aus höchstfesten Stählen - Hezler, Christian (Friedrich-Alexander-Universität Erlangen-Nürnberg, 2016)
The insufficient accuracy of failure prediction within the FE-simulation for advanced high strength steels impedes the production of car body components. Through the application of an additional stress based failure criterion, the rupture risk evaluation can be improved early on in the development of components. The consideration of bending loads in the definition of stress limit curves ensures a process based evaluation. The reader will be informed about the limit curve development as well as specific proposals for the improved execution of technological tests to make them more comparabl

Einsatz von Laserstrahlung zur Herstellung tribologich optimierter Oberflächentopographien - Geiger, Manfred; König, Werner; Tönshoff, H.K. (Werkstoffe für die Fertigungstechnik, 1998)
LFT Import::2019-08-05 (1590)

Elastomere-Pad Bending of Tubes for Reaching High Residual Formability - Geiger, Manfred; Nock, Marco (ESAFORM 2004, Proceedings of the 7th ESAFORM Conference, Trondheim, Norway, 2004)
LFT Import::2019-08-05 (1047)

Embossing of Metal Inserts for Subsequent Assembly Injection Moulding of Media Tight - Frey, Philipp; Heinle, Martina; Leisen, Christoph; Drummer, Dietmar; Merklein, Marion (Key Engineering Materials, 2015)
UnivIS-Import:2017-12-18:Pub.2015.tech.FT.FT-KT.emboss

Embossing of metal inserts for subsequent assembly injection moulding of media tight electronic systems - Frey, Philipp; Heinle, Martina; Leisen, Christoph; Drummer, Dietmar; Merklein, Marion (Key Engineering Materials, 2015)
Keywords: Metal forming; Microforming; Moulding

Energy based algorithms to solve initial solution in one-step finite element method of sheet metal stamping - Tang, B.T.; Zhao, Z; Hagenah, Hinnerk; Lu, X.Y. (Computer Methods in Applied Mechanics and Engineering, 2007)
One-step finite element method (also called inverse approach) is more and more widely used in the automobile industry because of its unique advantages. Initial solution is an essential issue to ensure the success of the non-linear resolution in the implicit static one-step finite element solver. In order to speed up the convergence of the Newton-Raphson iterations, different kinds of initial solution methods are known. These are studied and compared in this paper. Several examples are followed to show their performance and efficiency. However most of these methods are based on geometric considerations like the geometric mapping method or the radial length development method. This kind of geometry based mapping methods could not reflect all aspects of the actual forming process. Therefore, an energy based mapping algorithm was implemented and coupled with the reverse deformation method which is based on the assumption of linear elastic deformation. This novel algorithm is proposed to provide the initial solution of one-step finite element method. For a complicated sheet forming modeling initial solutions obtained by different energy based algorithms coupled with the reverse deformation method are then compared in this paper. The results show that the Desbrun quadratic energy method and the accordant parameterization method combined with the inverse deformation method respectively are universal, efficient and robust initial solution schemes for the one-step finite element method. © 2006 Elsevier B.V. All rights reserved.
LFT Import::2019-07-15 (262)
Keywords: Initial solution; One-step finite element method; Sheet metal stamping

Enhanced formability of aluminium blanks by local laser heat treatment - Merklein, Marion; Geiger, Manfred; Vogt, Uwe (Proceedings of the 5th LANE Conference, 2007)
LFT Import::2019-08-05 (1471)

Enhanced Formability of Ultrafine-Grained Aluminum Blanks by Local Heat Treatments - Merklein, Marion; Vogt, Uwe (Key Engineering Materials, 2009)
High strength aluminum blanks can be obtained by grain-refinement due to an Accumulativ Roll Bonding (ARB) process, in which two sheets are iteratively brushed, stacked on top of each other and subsequently rolled together. The high shear stresses during the rolling cycles result in an ultrafine-grained microstructure with an average grain size ranging between 200 to 1000 nm. Whereas the grain-refinement causes a drastically increased strength of the aluminum material, the formability of the ARB-blanks made of industrially used aluminum alloys such as the AA6016 deteriorates to the same degree as the strength rises. In this context, a local heat treatment of the ARB-blank reducing the material's strength and increasing its ductility in specific zones will allow to recover the blank's formability again. The research work presented in this paper studies the microstructural effects of a short-term heat treatment on the mechanical properties of ARB-blanks made of AA6016. Experimental investigations including hardness measurements, tensile tests as well as microscopic analyses show that heat treatments of only several seconds already result in significant increases of the material's ductility and decreases of the material's strength. By applying these microstructural mechanisms in terms of a specific heat treatment layout, functional gradients of strength and ductility adapted to the succeeding forming operation can be setup significantly enhancing the ARB-blank's formability.
EAM Import::2019-03-14

Enhanced Investigation of Flow and Necking Behavior of Sheet Metal within Layer Compression and Tensile Tests - Kuppert, Andreas; Merklein, Marion (Proc. of COMA 10, 2010)
LFT Import::2019-08-05 (295)

Enhanced numerical results on friction stir welded aluminium butt joints - Staud, Detlev; Giera, Artur; Merklein, Marion; Geiger, Manfred (Proceedings of the 12th International Conference on Sheet Metal (SheMet), 2007)
Friction stir welding is a newer technology to join materials in the solid phase. Therefore plenty of problems which appear by melting phase welding technologies for aluminium alloys are avoided by this process. This is the main chance for friction stir welding to be accepted and integrated in forthcoming applications, especially for uses out of aluminium alloys. Starting from former results for friction stir welding of aluminium this article deals with the determination of the constitutive material properties of friction stir welded aluminium tailored blanks with regard to the finite-element (FE) simulation of sheet metal forming. The FE simulation of the formability of welded sheet metal demands the knowledge of the precise mechanical properties of the base material as well as the characteristic zones of the weld seam, which are affected by friction stir welding. While ordinary tensile tests can only determine the constitutive behaviour of a simple tensile specimen, an optical strain measurement can be used to determine flow stresses of the base and of the welded material with an adapted tensile specimen, respectively. By the usage of the so called rule of mixture the advantages of this new approach is demonstrated with a comparison of the tensile forces within FE simulations and experimental validations. For this purpose specimen with the weld seam oriented perpendicular and parallel to the uniaxial loading direction are utilized.
LFT Import::2019-08-05 (1395)
Keywords: Friction stir welding; Mechanical properties; Simulation; Tensile test

Enhancement of a Constitutive Friction Law by Considering Plastic Smoothing of Rough Surfaces in Dependency on the Bulk Stresses - Beyer, Florian; Löffler, Maria; Willner, Kai; Engel, Ulf; Merklein, Marion (Tribology in Industry, 2016)
The aim of this work is the improvement of a constitutive friction law which has been identified for the specific demands of sheet-bulk metal-forming. The constitutive friction law determines the friction shear stress in dependency on the plastic smoothing of the surface roughness, which also affects the real contact area. An experimental setup is introduced to determine the change of the surface roughness, which is influenced by the tensile bulk stress in the workpiece. In order to model the experimental results, a well-established half-space model is presented and improved to consider strain hardening. The half-space model is used to determine the change of the contact area as a function of the tensile bulk stress. This interdependency is also reflected by the proposed constitutive friction law.
Keywords: friction; constitutive friction law; half-space model; elasto-plastic contact; strain hardening; bulk stresses; sheet-bulk metal forming

Enhancement of formability of aluminum alloys in multi-stage forming operations by a local intermediate heat treatment - Merklein, Marion; Lechner, Michael; Kuppert, Andreas (Production Engineering, 2012)
Within this paper a new approach to enhance the formability of aluminum alloys in multi-stage forming processes will be presented. The technology's key idea is the local adaption of the mechanical properties after a first forming step and their optimization for the subsequent forming operation. The partial change of the mechanical properties is obtained by a short term heat treatment between two forming steps. Based on the new property distribution the material flow during the second forming is improved and the formability of the material can be enhanced. The presented work covers all necessary steps for a successful application of the technology. After a material characterization in dependency of the pre-straining and the heat treatment, the heat affected zone, which is a result of the high heat conductivity of aluminum alloys was analyzed. In the end appropriate heat treatment layouts were designed via numerical simulation and the enhancement of formability was demonstrated with a real multi-stage forming process. © 2012 German Academic Society for Production Engineering (WGP).
LFT Import::2019-07-29 (1823)
Keywords: Enhancement of formability; Hardenable aluminum alloys; Local intermediate heat treatment; Multi-stage forming-process

Enhancement of springback prediction of AHSS parts by advanced friction modelling - Durmaz, U.; Heibel, S.; Schweiker, T.; Merklein, Marion; Berahmani, S.; Hol, J.; Naegele, P. (INTERNATIONAL DEEP-DRAWING RESEARCH GROUP CONFERENCE (IDDRG 2021), 2021)
CRIS-Team WoS Importer:2021-11-05

Enhancement of the Forming Limits for Orbital Formed Tailored Blanks by Local Short-term Heat Treatment - Hetzel, Andreas; Merklein, Marion; Lechner, Michael (Procedia Manufacturing, 2020)
Nowadays, the manufacturing industry faces opposing challenges like a reduction of carbon dioxide on the one hand and on the other hand an increasing weight due to higher safety standards and additional functions. Concepts like lightweight design and functional integration are essential to ensure a sustainable and individual mobility. Gear systems consist of multi-functional parts with a varying sheet thickness and different geometric elements. Since conventional manufacturing processes like shearing are reaching their limits due to complexity and a lack in efficiency, the application of Tailored Blanks is a promising approach to meet these requirements. Manufactured by orbital forming, these process-adapted blanks dispose a high material efficiency. A tumbling motion of the upper punch enables the material distribution, realizing functional components with different material thickenings. The substitution of steel by aluminum is a common approach to meet the demands of lightweight construction. However, the use of aluminum results in a decreased formability at a constant level of strength. In order to enhance the local forming limits, a short-term heat treatment can be applied, reducing the materials' strength, whereas the untreated areas still offer the initial properties. To transfer the results of fundamental research in Sheet-Bulk Metal Forming with conventional steel to the use of lightweight material, the precipitation hardenable aluminum alloy EN AW 6016 is investigated in an orbital forming process. Since the formability of aluminum is limited and the material flow during the process is three-dimensional, different heat treatment strategies are applied to a rotational-symmetric Tailored Blank and the resulting components are investigated regarding their geometry and mechanical properties. To increase the geometric complexity with regard to an industrial application, the transferability to a cyclic-symmetric layout is analyzed. To evaluate the potential of the heat treatment, the treated components are compared to Tailored Blanks manufactured without heat treatment.
CRIS-Team Scopus Importer:2020-06-05
Keywords: Aluminum EN AW 6016; Heat Treatment; Lightweight Design; Orbital Forming; Tailored Blanks

Enhancing Forming Limits by Using a Magnetorheological Fluid as Active Fluid Medium for Hydroforming - Rösel, Sebastian; Merklein, Marion (Steel research international: Special Edition: 10th International Conference on Technology of Plasticity, 2011)
The automobile industry has to preserve commodities by light weight constructions. It is to the forming technology to overcome the challenges of forming high complex part geometries, by offering more flexible forming technologies e.g. hydroforming, which are cost efficient and can utilize the whole formability of the used materials. One active deviance, which has prevented the application of hydroforming of blanks In serial production, is the sealing of the cavity In the flange area. To Insure a complete sealing, it Is necessary to remain below a defined ratio between cavity pressure and contact pressure In the flange area, which Is restricting the process window. This experimental work focuses on the Influence of the magnetorheological fluid Basonetic 5030 on the sealing ratio compared to mineral oil shell tellus 100. Experiments are carried out at different cavity and contact pressures with the media mentioned above. Additionally a defined magnetic flux density Is applied to the magnetorheological fluid In the flange area to Increase its viscosity. Afterwards cups are drawn with DC04 of a sheet thickness of 1 mm and the resulting cup geometries are measured. Various geometric parameters are compared to each other to identify the process latitudes and the possible process parameters. © 2011 Wiley-VCH Verlag GmbH & Co. KGaA. Weinheim.
LFT Import::2019-08-05 (1650)
Keywords: Forming processes; Hydroforming; Magnetorheological fluid (MRF); Sheet metal

Enhancing Process Limits of Blank Hydroforming - Merklein, Marion; Grüner, Martin; Rösel, Sebastian (Internationale Konferenz „Hydroumformung von Blechen, Rohren und Profilen“, 2012)
LFT Import::2019-08-05 (1813)

Enlargement of deep drawability of aluminium blanks - Merklein, Marion; Kerausch, Michael; Hußnätter, Wolfgang; Geiger, Manfred (Advanced Technology of Plasticity, Proceedings of the 7th ICTP, 2002)
LFT Import::2019-08-05 (1697)

Entwicklung einer CAD/CAM-Prozeßkette für die Herstellung von Blechbiegeteilen - Hoffmann, Martin (1992)
The sheet metal processing equipment of the chair for manufacturing technology allows for flexible production of complex bent sheet metal parts in small production runs. In this work a CAP-system was developed to support preproduction engineering and thus enhance the efficiency of the machine. This system is stands out due to its high degree of automation. The basis for this was the design of an integrated data model, tailored for the needs of preproduction engineering of sheet metal processing. The development of fast and efficient algorithms was made possible by constructing a feature oriented data model which represents sheet metal parts as shell parts and implementation of an attribute management system, that can process tolerance information. The automated processing of technological and expert knowledge was a main aspect of the development of the CAD/NC process chains. This not only makes the work of the designer easier, but also improves manufacturing quality and safety. The design and development of intelligent modules for the process chains, the technology processor for laser beam cutting and the automatic planning of bending states are described in detail. The integration of technological data and data of the manufacturing processes with the necessary interfaces to data bases and designer are addressed in particula

Entwicklung einer CAD/CAM-Prozeßkette für die Herstellung von Blechbiegeteilen - Hoffmann, Martin (Fertigungstechnik - Erlangen, 1992)
LFT Import::2019-07-15 (493)

Entwicklung einer Methode zur Prognose adhäsiven Verschleißes an Werkzeugen für das direkte Presshärten - Wieland, Michael (2015)
Im Rahmen dieser Arbeit wurde eine Methodik zur Prognose adhäsiven Verschleißes an Werkzeugen für das direkte Presshärten entwickelt. Es wurden die für den adhäsiven Verschleiß relevanten Prozessparameter Blechtemperatur und Flächenpressung in Abhängigkeit der Wärmebehandlung des eingesetzten Halbzeugs untersucht und in eine Formulierung zur Berechnung der Verschleißhöhe überführt. Ein weiterer Schwerpunkt der Arbeit war die Identifikation des Schädigungsverhaltens der eingesetzten Halbzeugbeschichtung, welche einen Haupteinfluss auf den sich einstellenden adhäsiven Übertrag darstellt. Nur durch den in dieser Arbeit entwickelten Ansatz kann eine qualitativ hinreichend genaue Prognose des sich auf Werkzeugen für das direkte Presshärten einstellenden adhäsiven Verschleißes durchgeführt werden. Dieser Ansatz kann als Grundlage zur Erweiterung auf unterschiedliche Werkzeugwerkstoffe genutzt werden, wodurch eine Identifikation des Werkzeugbereichs mit der höchsten Verschleißbeanspruchung ermöglicht wir

Entwicklung einer Methodik zur Herstellung von Tailored Blanks mit definierten Halbzeugeigenschaften durch einen Taumelprozess - Hildenbrand, Philipp (Friedrich-Alexander-Universität Erlangen-Nürnberg, 2019)
Sustainable production by a defined usage and thus saving of materials along the product development process is one central aspect to reduce emissions and contribute to climate protection. Improving the material efficiency can be realized by the application of process adapted semi-finished parts, so called tailored blanks which can for example be manufac-tured an orbital forming process. In this context, the central objective of this work is the fundamental scientific investigation of an orbital forming process for manufacturing tailored blanks with defined part properties out of steel materials with different strength. To achieve the set objective, the fundamental causeeffect relationships as well as the influence on the resulting part properties will be identified on the basis of the main process parameters. Based on these results, process limits will be identified and a methodology will be derived which enables a defined adjustment of the part properties. This methodology will be validated by additional experiments in order to verify made statements regarding the generalization of the findings. Overall, this leads to a broad and deeper process understanding regarding the influence of different process parameters on the properties of orbital formed tailored blanks out of various steels. This enables the realization of defined properties specifically adapted for their field of application and in the end an improved material efficiency and saving of resource

Entwicklung einer Wissenserwerbskomponente für die Biegestadienplanung - Geiger, Manfred; Hoffmann, Peter; Backes, Frank (Werkstattstechnik, 1993)
LFT Import::2019-07-15 (404)

Entwicklung eines benutzerorientierten Werkstattprogrammiersystems für das Laserstrahlschneiden - Kollera, Harald (Friedrich-Alexander-Universität Erlangen-Nürnberg, 1993)
Based on an analysis of the task NC programming in a shop oriented manufacturing organization a modular programming system was designed, which is structured analogous to the task. The restrictions of and demands on the flexible manufacturing of sheet meta1 parts are considered as well. Using common modelling approaches, a data model was developed which covers the whole task from the description of the workpiece to the optimization of the NC program. Another advantage of the model is that it can easily be expanded. The main focus in the development of the programming system was put on technology planning. A method was introduced which uses relations of the nearest neighbour to reduce the computing time. With this method it is possible to combine interactive functions with automatic control mechanisms without enlarging the response time of the system. For the simulation and optimization of NC programs a module was developed which uses the data model as a basis to link NC simulation and technological functions. For instance, critical contour cuts can automatically be detected with the help of the relations of the nearest neighbour while rebuilding the model from a NC progra

Entwicklung eines Datenmodells für die Fertigungsvorbereitung von Blechbiegeteilen - Geiger, Manfred; Hoffmann, Martin (Blech, Rohre, Profile, 1992)
LFT Import::2019-07-15 (375)

Entwicklung eines mesoskopischen Modells zur Abbildung von Größeneffekten in der Kaltmassivumformung mit Methoden der FE-Simulation - Geißdörfer, Stefan (Friedrich-Alexander-Universität Erlangen-Nürnberg, 2010)
With considering the microstructure, the mesoscopic model developed in this study is able to map size dependent forming behaviour to the simulation results by using finite element method. The knowledge of the local deformation behaviour enables a size-dependent design of the deformation process as well as the calculation of size-dependent process scatte

Entwicklungen zum Präzisionslaserschneiden - Geiger, Manfred; Nuss, Rudolf (Neuere Entwicklung in der Blechbearbeitung - Tagungsband zum Seminar, 1988)
LFT Import::2019-08-05 (282)

Entwicklung prozessüberwachender Regelkreise für flexible Formgebungsprozesse - Hutterer, Angelika (Friedrich-Alexander-Universität Erlangen-Nürnberg, 2005)
Flexible forming processes like laser forming are using independent tools and are thus suitable for fast and efficient product development. High accuracy and reproducibility of the products is the precondition of the production. This thesis describes methods and algorithms tor a feature based closed loop control system. The closed loop control system is realized exemplarily for the laser forming of extrusions and the laser adjustment of free form surfaces. The systems could be applied in the field of space frame technology or in the adjustment of warpage in the car body industr

Entwicklung von Ansätzen zur Erweiterung der Prozessgrenzen in industrienahen Laborversuchen anhand einer Streifenzuganlage - He, Franz; Merklein, Marion; Dechant, Stefanie (Warmumformung von höchstfesten Vergütungsstählen: Tagungsband zum 17. Erlanger Workshop Warmblechumformung, 2022)
Zur Umsetzung der immer weiter steigenden Anforderungen an die passive Sicherheit bei gleichzeitiger Verringerung des Bauteilgewichts spielt die Warmumformung ein wesentliche Rolle. Die Technologie des Presshärtens bietet dabei die Möglichkeit zur Herstellung höchstfester Strukturbauteile bei gleichzeitig reduzierter Wandstärke. Um Verzunderung zu unterbinden und Korrosionsschutz im Prozess zu gewährleisten, wird auf die verwendeten Blechhalbzeuge eine Aluminisum-Silizium(AlSi)-Beschichtung aufgebracht. Die Werkstück-beschichtung wurde als Hauptursache für die adhäsive Verschleißbildung identifiziert und hat somit einen entscheidenden Einfluss auf die Werkzeugstandzeit und die Qualität von pressgehärteten Bauteilen. Die Entwicklung effektiver Maßnahmen zur Verringerung von Reibung und Verschleiß setzt ein grundlegendes Prozessverständnis in Bezug auf das tribologische System voraus. Vor diesem Hintergrund werden die industriellen Presshärtebedingungen im Labormaßstab anhand von Streifenzuganlagen abgebildet. Ein limitierender Faktor im Flachbahnzugversuch in bisherigen Untersuchungen ist die erreichbare Flächenpressung. Während die existierende Anlage eine theoretische maximale Flächenpressung von 130 MPa umsetzen kann, können bereits Anpressdrücke von 7,5 MPa zur Ausbildung von Kaltverschweißungen durch Abscherung der Beschichtung und Reibzahlabbrüchen führen. Vor diesem Hintergrund werden Störfaktoren im Versuch identifiziert, um die vorhandene Warmstreifenziehanlage zu modifizieren und Versuche unter industrierelevanten Parametern durchzuführen. <
Keywords: Streifenzugversuch; Reibkoeffizient; Verschleiß; 22MnB5

Entwurf eines erweiterten CAD/CAP-Datenmodells - Greska, Wolfgang; Hoffmann, Peter; Geiger, Manfred (Blech, Rohre, Profile, 1994)
LFT Import::2019-07-15 (609)

Entwurf komplexer Aktorsysteme für das Laserstrahljustieren - Müller, Burkhard; Huber, Alexander (Laser in der Elektronikproduktion & Feinwerktechnik - Tagungsband des 3. Erlanger Seminars LEF 2000. Erlangen 8.-9.3., 2000)
LFT Import::2019-08-05 (792)

Environmentally benign tribo-systems for metal forming - Bay, Niels Oluf; Azushima, A.; Groche, P.; Ishibashi, I.; Merklein, Marion; Morishita, M.; Nakamura, T.; Schmid, S.; Yoshida, M. (CIRP ANNALS - Manufacturing Technology, 2010)
The growing awareness of environmental issues and the requirements to establish solutions diminishing the impact on working environment as well as external environment has initiated ever increasing efforts to develop new, environmentally benign tribological systems for metal forming. The present paper gives an overview of these efforts substituting environmentally hazardous lubricants in cold, warm and hot forging as well as sheet forming and punching/blanking by new, less harmful lubricants and furthermore describes other measures directed towards the same goal such as development of anti-seizure tool materials and coatings and application of structured workpiece and tool surfaces. © 2010 CIRP.
LFT Import::2019-08-05 (1897)
Keywords: Environmental impact; Lubricants; Metal forming tribology; Structured tool surfaces; Structured workpiece surfaces; Tool coatings; Tool materials

Erarbeitung einer Methodik zur Abbildung tribologischer Bedingungen im Presshärteprozess unter Verwendung einer Warmstreifenziehanlage mit Umlenkung - He, Franz; Harms, Arnold; Merklein, Marion (Tagungsband zum 19. Erlanger Workshop Warmblechumformung 2024, 2024)
Im Automobilbereich hat sich das Presshärten als Herstellungsverfahren für sicherheitskritische Komponenten in der Karosserie wie der B-Säule etabliert. Durch die Austenitisierung des Bor-Mangan-Stahls bei Temperaturen über Ac3 kann die Maßhaltigkeit gesteigert und die Rückfederung gesteigert werden, wenn bei hohen Temperaturen umgeformt wird. Der Kontakt mit dem gekühlten Werkzeug löst zusätzlich eine Martensithärtung aus, wodurch das finale Bauteil bei Raumtemperaturen gute mechanischen Eigenschaften und insbesondere hohe Festigkeiten aufweist. Aufgrund der hohen Temperaturen ist ein Einsatz von Schmierstoffen bisher nicht möglich. Um die auftretenden tribologischen Eigenschaften zu untersuchen werden bisher Laborversuche über eine flache Ebene genutzt, die die Kontaktbedingungen im Flanschbereich wiedergeben. Da sich der kritische Bereich der Ausdünnung und Verschleißentstehung im Bauteil auf die Kontaktzone im Matrizeneinlaufradius konzentriert, wurde mit dem Streifenzug mit Umlenkung ein neuer Versuchsprüfstand adaptiert, um die Verhältnisse in der Wirkfuge am Werkzeugradius wiedergeben zu können.<br
Keywords: Presshärten; Tribologie; Umlenkung; 22MnB5; Aluminium-Silizium

Erarbeitung einer Methodik zur semiempirischen Ermittlung der Umwandlungskinetik durchhärtender Wälzlagerstähle für die Wärmebehandlungssimulation - Lutz, Stefan (Friedrich-Alexander-Universität Erlangen-Nürnberg, 2019)
The numerical simulation of heat treatment processes is becoming increasingly important in the design of large and complex bearing components. Since the required thermophysical and thermomechanical material properties depend strongly on the microstructural composition of the material, a precise description of the phase transformation behavior is of crucial importance for the accuracy of the heat treatment simulation. Against this background, the overall objective of this work is to generate a more detailed understanding of the factors influencing the phase transformation of through hardening bearing steels and to develop a methodology for simplified determination and exact mathematical mapping of the transformation behavior for the FE simulation of heat treatment processes. The knowledge gained in this work enables a more efficient approach to the simulation of heat treatment processes, as the time and effort for characterizing new material batches as well as known materials with different austenitizing conditions is considerably reduced. In addition, the quality of the simulation results is significantly improved by the more accurate mapping of the transformation behavio

Erarbeitung eines grundlegenden Verständnisses zum Fließpressen betriebsangepasster Verzahnungen für den Einsatz in der Materialpaarung Metall-Kunststoff - Rohrmoser, Andreas (Friedrich-Alexander-Universität Erlangen-Nürnberg, 2024)
Zahnräder stellen integrale und unverzichtbare Maschinenelemente dar. Für Anwendungen im niedrigen und mittleren Leistungsbereich ist der Einsatz trockenlaufender Zahnradgetriebe der Materialpaarung Metall-Kunststoff vielversprechend, da die spezifischen Vorteile beider Werkstoffe kombiniert werden. Im Betrieb tritt allerdings Verschleiß auf, wodurch die Einhaltung der funktionsrelevanten Toleranzen und die Lebensdauer des Getriebes begrenzt werden. Innerhalb der Paarung beeinflussen die Eigenschaften des metallischen Partners das Verschleißverhalten wesentlich, weshalb dessen fertigungsbedingten Bauteileigenschaften eine entscheidende Bedeutung zukommt. Vor diesem Hintergrund bietet der Einsatz des Kaltfließpressens zur Verzahnungsherstellung Potential aufgrund kurzer Prozesszeiten, einer hohen Materialeffizienz sowie guten erzielbaren mechanischen Eigenschaften und einer hohen resultierenden Oberflächengüte. Herausforderungen sind allerdings die geringe Verzahnungsgenauigkeit sowie eine hohe Werkzeugbeanspruchung. Um das Einsatzpotential fließgepresster Zahnräder in der Materialpaarung Metall-Kunststoff zu steigern und den Verschleiß zu reduzieren, wird in dieser Arbeit ein grundlegendes Verständnis zur betriebsangepassten Herstellung erarbeitet. Dies beinhaltet die Ermittlung von Einflussgrößen der metallischen Verzahnung auf das Verschleißverhalten sowie die Identifikation der auftretenden Verschleißmechanismen. Des Weiteren werden Maßnahmen zum Fließpressen einsatzfertiger Verzahnungen erforscht. Hierzu werden Einflussgrößen auf die Prozess- und Bauteileigenschaften sowie die zugrundeliegenden Wirkzusammenhänge ermittelt. Aufbauend darauf werden Stellhebel zur systematischen Beeinflussung der umforminduzierten Bauteileigenschaften der fließgepressten Verzahnungen entwickelt. Abschließend werden anwendungsgerechte Empfehlungen zur Herstellung betriebsangepasster, einsatzfertiger metallischer Zahnräder für die Materialpaarung Metall-Kunststoff durch Kaltfließpressen abgeleit

Erarbeitung eines Prozessverständnisses zur Verbesserung der tribologischen Bedingungen beim Presshärten - Schwingenschlögl, Patrik (Friedrich-Alexander-Universität Erlangen-Nürnberg, 2020)
With the growing numbers of automobiles in Germany, the demands of modern passenger cars regarding safety and efficiency constantly increase. The application of hot stamped parts allows reducing the weight of the body in white and simultaneously improving passenger safety. However, high forming temperatures prevent the use of lubricants, so that high friction and tool wear limit the process window. In order to use the full potential of the hot stamping process, the development of measures to reduce friction and wear is needed. For this purpose, a method for characterizing the tribological conditions within hot stamping has been elaborated within this work. This method allows for analyzing the friction and wear conditions reproducible and specifically. With this method, a comprehensive process understanding regarding the predominant tribological conditions has been created. Based on the created process understanding tool-side measures for reducing friction and wear have been identified. The experimental investigations indicate that the choice, as well as the heat treatment of the tool material and the application of PVD-tool-coatings, can reduce friction and wear. Concluding, the transferability of the findings of the strip drawing tests on a B-pillar-geometry in laboratory-scale was shown. Thus, it can be concluded that the basic findings of this work can be used for hot stamping processe

Erarbeitung von Grundlagen zur Abbildung des tribologischen Systems in der Umformsimulation - Zöller, Fabian (Friedrich-Alexander-Universität Erlangen-Nürnberg, 2016)
The tribological system has a major impact on the process window of forming process in the manufacturing of car body parts. Therefore in the design process a realistic mapping of friction in simulation is necessary. In this work the influence of several for the manufacturing of car body parts relevant process variables on the friction coefficient have been investigated. Based on these findings a pressure dependent friction model has been developed. The verification of this model has shown a more realistic representation of the sheet thickness distribution in simulation by using the new approach in comparison to the industrial standar

Erfassung von Kontaktspannungen im Flansch während wirkmedienbasierter Blechumformprozesse - Merklein, Marion; Trägler, Horst; Blankl, Andreas (Automobiltechnik in Bayern, 2009)
LFT Import::2019-07-29 (1583)

Erhöhung der Lebensdauer von Werkzeugen durch Oberflächenstrukturierung - Popp, Uwe; Engel, Ulf (17.Jahrestreffen der Kaltmassivumformer, 2002)
LFT Import::2019-08-05 (1681)

Erkennung von Blechteilen mit Neuronalen Netzen - Wilke, Peter; Geiger, H; Greska, Wolfgang; Behrendtz, Jürgen (Zeitschrift für Wirtschaftliche Fertigung und Automatisierung, 1993)

Ermittlung des Reibverhaltens von Tailor Welded Blanks im Näpfchenziehversuch - Tolazzi, Massimo; Lamprecht, Klaus; Merklein, Marion (Tagungsband zum XXV. Verformungskundlichen Kolloquium 04.-07.03., 2006)
LFT Import::2019-08-05 (1259)

Ermittlung des Vorspannungszustandes von Matrizenverbänden mittels Ultraschall - Putz, Alexander; Engel, Ulf (Neuere Entwicklungen in der Massivumformung, 2005)
LFT Import::2019-07-16 (1132)

Ermittlung funktioneller Zusammenhänge beim Fügen von Stanzmuttern und Blechhalbzeugen - Weiss, Miriam (Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 2019)
Der zunehmende Einsatz moderner, insbesondere höher- und hochfester Werkstoffe zwingt die Stanzmuttertechnologie zu einem ständigen Weiterentwicklungsdruck. In der Praxis erfolgt die Durchführung anwendungstechnischer Untersuchungen rein experimentell. Dieses Trial-and-Error-Prinzip führt zu extrem langen Entwicklungszeiten. Zudem fehlt es an einem grundlegenden Prozessverständnis. Im Rahmen dieser Arbeit wurde durch die Anwendung der numerischen Simulation ein breites Verständnis des Fügeprozesses von Stanzmutterverbindungen und des Versagensverhaltens entwickelt. Durch die Werkstoffflussanalyse in Abhängigkeit des Prozessfortschritts wurden funktionelle Zusammenhänge zwischen geometrischer Verbindungsausbildung und mechanischer Verbindungsfestigkeit ermittelt und Maßnahmen zur werkstoffspezifischen Adaption von Stanzmutterverbindungen, insbesondere zur Erweiterung der Verfahrensgrenzen, identifizier
Keywords: mechanisches Fügen; numerische Fügeprozesssimulation; Stanzmutter

Ermittlung prozessrelevanter Werkstoffkenngrößen für die Blechumformung bei erhöhten Temperaturen - Merklein, Marion; Hußnätter, Wolfgang; Hecht, Joachim (Tagungsband Werkstoffprüfung 2006, 2006)
LFT Import::2019-08-05 (1319)

Ermittlung temperaturabhängiger Werkstoffkennwerte für die Auslegung von Halbwarm- und Warmumformprozessen - Kuppert, Andreas; Merklein, Marion (Metall, 2008)
LFT Import::2019-07-29 (290)

Ermittlung vin thermischen und mechanischen Werkstoffeigenschaften höchstfester Vergütungsstähle für das Presshärten - Merklein, Marion; Geiger, Manfred; Lechler, Jürgen (Tagungsband VDEh-Workshop: Moderne thermomechanische Prozessstrategien in der Stahlumformung, 2007)
LFT Import::2019-08-05 (1459)

Ermüdungsbruchversagen hartstoffbeschichteter Werkzeugstähle in der Kaltmassivumformung - Hinsel, Christian (Friedrich-Alexander-Universität Erlangen-Nürnberg, 2000)
The application of modern hard coatings provides a considerable potential to increase tool life if wear is the dominating reason for failure. Particularly in cold forging, however, tool life is often limited by fatigue and the resulting crack initiation. The Dr.-Thesis discusses the issue in which way different hard coatings influence the fatigue behaviour of tools steels. The results of fundamental low- and high-cycle fatigue experiments lead to conclusions which properties (especially residual stresses and surface topography) of the coated steel influence its strength in which way. Therefore a cold working steel (X 155 CrVMo 12 1) and a high-speed steel (S 6-5-2), coated with various materials by PVD and CVD, were investigated. Inferences from the experimental and numerical analysis of the residual stress distribution in coating and substrate provide insight into the load conditions. Thus, the decisive factors which influence the fatigue behaviour of coated tool steels are determined. Furthermore, the capabilities of surface and coating technologies to reduce the risk of premature fatigue crack initiation are discussed. The results of tool monitoring of cold forging punches demonstrates how advanced duplex treatment (plasma-nitriding and subsequent PVD coating) succeeds in increasing the tool life considerabl

Erratum: “Potential of joining dissimilar materials by cold formed pin-structures” (Journal of Materials Processing Tech. (2020) 283, (S0924013620301114), (10.1016/j.jmatprotec.2020.116697)) - Kraus, Martin; Merklein, Marion (Journal of Materials Processing Technology, 2021)
The publisher regrets that the below images appear incorrectly in the original article. Figure 3 should appear as follows:
CRIS-Team Scopus Importer:2021-05-14

Erstellung eines Werkstofforientierten Fertigungsprozessfensters zur Steigerung des Formgebungsvermögens von Aluminiumlegierungen unter Anwendung einer zwischengeschalteten Wärmebehandlung - Klaus, Kathleen (Friedrich-Alexander-Universität Erlangen-Nürnberg, 2015)
In the conventional sheet metal forming aluminum alloys exhibit compared with steel material-specific forming limits. This book shows how the use of an intermediate heat treatment allows an increase in the capability of forming of the selected naturally hardened aluminum alloy AA5182. The intermediate heat treatment in this case represents a novel process technology and is carried out using two different heating strategies, the global and the local induction heating furnace, with respect to the series-production of chassis components. The aluminum blank is pre-strained during an initial cold-forming step, then heat treated and then drawn to its final geometry at room temperature. The work provides information on the impact of heat treatment on the resulting material and forming properties based on different input parameters. In addition to the definition of a material-oriented process window, the reader is presented a method approach to take account of the material properties achieved in industrial FE simulatio

Erst umdenken, dann umformen - Diehl, Alexander; Summerauer, I.; Heimann, T.; Franke, Volker; Engel, Ulf; Schulze-Niehoff, H.; Vollertsen, Frank (Mikroproduktion, 2006)
LFT Import::2019-07-16 (1324)

Erweitertes Mesoskoisches Modell zur FE-Berechnung komplexer Mikroumformprozesse - Geißdörfer, Stefan; Engel, Ulf; Geiger, Manfred (Proceedings of the 2nd Colloquium of DFG Priority Program Process Scaling, 2005)
LFT Import::2019-08-05 (1201)

Erweiterung des Prozessfensters für das lokale Aufkohlen bei erhöhten Temperaturen eines pressgehärteten Komplexphasenstahls - Risse, Jan Henning; Merklein, Marion (Warmumformung von höchstfesten Vergütungsstählen: Tagungsband zum 18. Erlanger Workshop Warmblechumformung, 2023)
Als Leichtbaustrategie werden in der Automobilkarosserie, z. B. als B-Säulen, höchstfeste Stähle mit maßgeschneiderten Eigenschaften zunehmend für crashrelevante Bauteile eingesetzt. Mit dem Verfahren Tailored Carburization können Bauteile lokal verstärkt werden, ohne die Blechdicke zu erhöhen und ohne die Notwendigkeit von komplexer Werkzeugtechnik. Damit hat dieses Verfahren das Potenzial, bei Leichtbauteilen mit verformungsfreien Zonen, z.B. bei Batteriegehäusen, oder in Kleinserien Verwendung zu finden. Normalerweise wird die Aufkohlung bei 950 °C durchgeführt, wobei die höchsten Festigkeiten bei langen Zeiten von bis zu 6 Stunden erreicht werden, was die Gesamtprozesszeit verlängert. Durch die Erhöhung der Temperatur nimmt die Kohlenstoffdiffusion zu, was eine kürzere Wärmebehandlungszeit und folglich eine kürzere Prozessdauer ermöglicht, wie bereits grundlegend gezeigt wurde. Ziel dieser Untersuchung ist es daher, den Einfluss der einzelnen Aufkohlungsparameter beim Diffusionshärten auf die mechanischen Eigenschaften des aufgekohlten und gehärteten Komplexphasenstahls CP-W® 800 zu identifizieren sowie das Prozessfensters zu erweitern.<br
Keywords: Presshärten; Maßgeschneiderte Eigenschaften; Aufkohlung

Erweiterung und Verbesserung von Versuchs- und Auswertetechniken für die Bestimmung von Grenzformänderungskurven - Kuppert, Andreas (Friedrich-Alexander-Universität Erlangen-Nürnberg, 2015)
In this work, methods for the determination of forming limit curves have been investigated. Influencing parameters were analyzed for the test and its evaluation. As a result, a new time-based evaluation method was developed and the applicability to tests at elevated temperatures demonstrate

Erzeugung von Mikrostrukturen mittels Laserstrahlung - Eßer, Gerd; Roth, Stephan; Krauß, Hans-Joachim (Idee-Vision-Innovation, Festschrift anläßlich des 60. Geburtstages von Professor Manfred Geiger, 2001)
LFT Import::2019-07-15 (913)

Establishment of a new biomechanical measurement method for surface deformation of bone by force application via dental implants—a pilot study - Matta, Ragai; Riegger, Katharina; Trägler, Horst; Adler, Werner; Eitner, Stephan; Wichmann, Manfred; Motel, Constantin (Applied Sciences, 2021)
Purpose: To date, the qualitative and quantitative recording of biomechanical processes in dental implants represents one of the greatest challenges in modern dentistry. Modern, dynamic, 3D optical measurement techniques allow highly constant and highly accurate measurement of biomechanical processes and can be superior to conventional methods. This work serves to establish a new measurement method. Materials and Methods: A comparative analysis was undertaken for two different measurement systems, two conventional strain gauges versus the 3D optical two-camera measurement system ARAMIS (GOM GmbH, Braunschweig, Germany), as they detected surface changes on an artificial bone block under masticatory force application. Two implants (Straumann Standard Implants Regular Neck, Straumann GmbH, Freiburg, Germany) were placed in the bone block, and three different three-unit bridges were fabricated. Increasing masticatory forces, from 0 to 200 N, were applied to the bone block via each of these bridges and the inserted implants. Fifteen repetitions of the test were performed using a universal testing machine. The computer unit of the ARAMIS system was used to simultaneously integrate the surface changes recorded by the strain gauges and the ARAMIS system. The areas on the bone block examined by the dynamic 3D optical measurement method corresponded exactly to the locations and extent of the strain gauges. A statistical comparative analysis was carried out separately for the strain gauges and the corresponding optical measuring surface at the defined force magnitudes. The equivalence test and the intraclass correlation served as statistical means. Results: In the case of the intraclass correlation, a clear concordance of both measurement methods could be shown for all examined cases. For the equivalence test, no significance could be shown in individual cases. Conclusion: The accuracy of the modern, dynamic, 3D optical measurement method is comparable to that of conventional strain gauges. On this basis, versatile new research approaches in the field of biomechanics of dental implants can be pursued by establishing this method.
CRIS-Team Scopus Importer:2021-09-03
Keywords: Bone deformation; Dental implants; Implant biomechanics; Strain

Estimation of Tool Life in Bulk Metal Forming Based on Different Failure Concepts - Falk, Bernd; Engel, Ulf; Geiger, Manfred (Journal of Materials Processing Technology, 1998)
LFT Import::2019-07-16 (1155)
Keywords: Cold forging; Fatigue; Finite elements; Tool life

Es werde Strom - Dietrich, Simon; Trägler, Horst; Otto, Andreas (Design & Elektronik, 2007)
LFT Import::2019-07-16 (1398)

Evaluation and quantification by electron back-scattering diffraction of the microsturcture of laser-crystallized silicon thin films - Christiansen, S.; Nerding, M.; Eßer, Gerd; Urmoneit, U.; Otto, Andreas; Strunk, H.P. (Proceedings of the Microscopy of Semiconducting Materials XII Conference, 2001)
LFT Import::2019-08-07 (877)

Evaluation of Crack Propagation During Cyclic Bending of Wire Strip - Biallas, Alina; Merklein, Marion (Proceedings of the 14th International Conference on the Technology of Plasticity - Current Trends in the Technology of Plasticity, 2024)
Steel fibers applied as concrete reinforcement like in Ultra High Performance Concrete reduce the wall thickness and thus the amount of concrete [1]. The process chain notch rolling and cyclic bending presents the foundation of an ecologically and economically efficient approach for production of steel wire fibers. For fundamental perception of the characteristics and interdependencies of the innovative production method, analysis by experimental model processes is required. Previous research determined influence of various process parameters on crack propagation [2], which is further analyzed in this study. As testing material, a DP600 sheet metal (t0 = 0.8 mm) is applied. Cyclic bending tests of wire strip with staggered amounts of cycles and varying bending angles are performed and evaluated based on load curves and micrographs. The analysis supplies identification of stages of crack propagation, which allows recommendations for process design regarding controllability and geometry of fracture. For supporting the analysis, stamping and cyclic bending is numerically implemented in the simulation software LS DYNA to picture the present strain stage applied during bending. The process evaluation together with the built simulation model can later be used as reference for a suitable numerical modeling of crack propagation that will enable a more flexible analysis of the process chain and parameter effects by simulation.<br
Created from Fastlane, Scopus look-up
Keywords: Bending; Damage; Crack propagation

Evaluation of failure behaviour of sheet metals - Affronti, Emanuela (Friedrich-Alexander-Universität Erlangen-Nürnberg, 2020)
The full exploitation of sheet metal formability is crucial for process optimization. This applies in particular to the automotive industry, in which the current trend is in the development of lightweight structures. Nevertheless, the standard evaluation methodology shows weaknesses for brittle materials. In the present study, a detailed analysis of the failure mechanisms for different material classes was carried out to improve the failure limit evaluation. The aim was to analyse the validity of the definition of the onset of necking in order to assure the correct prediction of the deformation limits, including those that do not show any localizations. The knowledge gained was used to define a validity window using pattern recognition methodology and to optimize the forming limit evaluation while taking into consideration the peculiarities of the different material

Evaluation of kinematic hardening models for multiple stress reversals under continuous cyclic shearing and multi - step bending - Rosenschon, Martin; Suttner, Sebastian; Merklein, Marion (LS-DYNA Forum 2015, 2015)
LFT Import::2019-08-05 (2125)

Evaluation of Material Behavior for Wire Strip under Cyclic Bending Load and Preparation of an Experimental Test Method - Biallas, Alina; Merklein, Marion (Paper presented at ESAFORM 2021, 2021)
Steel fibers as concrete reinforcement improve the building material’s mechanical properties and enlarges its field of application. The production of steel fibers by the process chain notch rolling and cyclic bending promises energetic improvement compared to the conventional manufacturing process wire drawing. The innovative procedure is not yet researched extensively and modelling of the material behavior brings with it many challenges. Different stress states of both process steps require various material models and material failure must be considered. The study brings an appropriate modelling of the test sheet metal DP600 with a thickness of t0 = 0.8 mm for the second process step into focus. The wire strip’s notches are exposed to a cyclic tension-compression load for which high strength steel exhibits early yielding and a distinct transient region of the stress-strain curve after load reversal. For this reason, the isotropic-kinematic hardening model by Chaboche and Rousselier determined in tension-compression tests is validated by cyclic bending tests. For considering crack initiation, an appropriate ductile damage model for depicting material fatigue is identified. To allow practical realization of the process and validation of the material model, an experimental test method for manufacturing wire strip samples by notch stamping is introduc
Keywords: Kinematic hardening; Damage; Steel fibers

Evaluation of testing methods for the characterization of material properties under plane strain - Lenzen, Matthias; Merklein, Marion (INTERNATIONAL DEEP-DRAWING RESEARCH GROUP CONFERENCE (IDDRG 2022), 2022)
CRIS-Team WoS Importer:2023-01-20

Evaluation of the friction and wear behavior of a-C:H coatings for lubricant-reduced sheet metal forming - Reblitz, Jonas; Zettl, Bastian; Seynstahl, Armin; Orgeldinger, Christian; Tremmel, Stephan; Merklein, Marion (Materials Research Proceedings, 2024)
Industrial companies are confronted with increasing demands for sustainability, challenges in the availability of raw materials as well as rising energy and labor costs. Thus, technological measures for improving the ecologic and economic potential of production are required. An important production stage for the manufacturing of metal-based products is sheet metal forming which consists of several production steps. Initially, the semi-finished sheets are lubricated with oil to reduce friction in the actual forming stage and afterwards they have to be cleaned. One approach for the decrease of production costs and increase of sustainability is the avoidance or reduction of oil-based lubricants and hence subsequent cleaning of the sheet metal parts. However, reducing the amount of lubrication leads to higher friction and wear. Consequently, the part quality as well as tool lifetime are significantly decreased. To meet these challenges, surface modifications for the reduction of wear can be applied. In this study, diamond like carbon (DLC) tool coatings were combined with minimum quantities of a solid lubricant on semi-finished parts to analyze the potential of the coatings for beneficial friction conditions. In this context, suitable a-C:H coating systems were needed to be identified. The associated friction and wear behavior was evaluated as a function of the lubricant amount for different variants of semifinished parts. Initially, several a-C:H coatings were generated with varying deposition parameters. Promising variants regarding layer adhesion were analyzed for sheet metal forming in terms of tribological behavior. The resulting coefficients of friction (CoF) and wear resistance were investigated with strip drawing tests. For the comparison of the results over different industrially relevant sheet metals, two aluminum alloys as well as one steel material with different zinc coatings were evaluated. For all materials, the amount of solid lubricant was varied in a range below 0.8 g/m2 up to a completely dry condition without lubrication. Introduction
CRIS-Team Scopus Importer:2024-11-08
Keywords: DLC Coatings; Physical Vapor Deposition (PVD); Sheet Metal; Tribology

Evaluation of the properties of AA7020 tubes generated by a heat treatment based hydroforming process - Reblitz, Jonas; Trân, Ricardo; Kräusel, Verena; Merklein, Marion (SheMet2023, 2023)
Energy efficiency and sustainability are getting more and more relevant in society and industry. Especially energy-intensive sectors offer a high potential for power savings. Thus, different lightweight strategies are applied in the automotive sector. In this context, high strength profile components are used as crash structures. As an example, these profiles are deployed to protect the battery of electrically powered vehicles. Therefore, high strength aluminum alloys of the 7xxx series are suitable for compensating the high battery weight partly. Compared to steel, this material is characterized by a high strength-to-weight ratio as well as an increased thermal conductivity. However, one challenge in forming high strength aluminum alloys is the limited formability at room temperature. For this purpose, heat treatment based process routes for tube hydroforming are investigated within this research work. By the combination of W-temper forming and hydroforming complex part geometries can be generated. A subsequent artificial ageing process realizes the required high strength of the profiles. Using AA7020 tubes, the properties of a demonstrator geometry are compared to the initial state T6 of the semi-finished parts. For this purpose, the wall thickness distribution and the grain structure are evaluated. Thereby, the influence of forming and heat treatment on the geometrical and microstructural properties is to be analyzed. For the evaluation of the achievable hardening of the aluminum alloy, the mechanical properties are investigated by tensile tests. This investigations provide an assessment of the process route under industry-related conditions.<br
Keywords: Heat Treatment; Hydroforming; Tubes

Evaluation on influences of thin lubricant on fringe projection measurements - Metzner, Sebastian; Reuter, Tamara; Hausotte, Tino (Optical Technology and Measurement for Industrial Applications, 2019)
Sheet bulk metal forming processes pose challenges for fringe projection systems, as the lubricant applied for forming could influence the measurement result. The lubricant layer has an expected film thicknesses smaller than 35 μm after the forming process. This paper presents an approach for the measurement of the lubricant layer influence on fringe projection measurements. The lubricant (Beruforge 152DL) used for the forming process and investigated in this paper has special characteristics like a water-based basic fluidity and wax particles for friction reduction as component of the liquid. A newly developed fluid film thickness standard represents the film thickness in a continuous range. This paper shows the impact on the standard deviation of the measurement results and a significant deviation of the detected surface on fluid film thickness standard with the applied lubricating film.
Keywords: fringe projection system; lubricant measurement; sheet bulk metal forming

Evaluierung von Modellen zur Beschreibung der Umwandlungsplastizität durch experimentelle Untersuchungen an einem Wälzlagerstahl - Lutz, Stefan; Weninger, J.; Helldörfer, B.; Merklein, Marion (9. Erlanger Workshop Warmblechumformung, 2014)
LFT Import::2019-08-05 (2064)

Evolution of surface topography in microforming - Engel, Ulf; Weidel, Stephan (Proceedings of the 3rd International Conference on Tribology in Manufacturing Processes ICTMP, 2007)
LFT Import::2019-08-05 (1447)

Evolution of yield loci for aluminum alloy AA6016 and deep drawing steel DC06 under the influence of non-linear strain paths - Merklein, Marion; Suttner, Sebastian (Key Engineering Materials, 2013)
The application of modern materials plays an important role directly under the aspect of lightweight potential. To exploit these options effectively a numerical accurate reproduction of the material behavior is indispensable. Especially in the case of large deformations a directional and strain rate dependent hardening behavior can be observed. By disregarding this effect significant failure in the computed stress state can arise, which can conduct to a corruption of the spring-back forecast. Within this contribution a new test method for analyzing the evolution of subsequent yield loci under strain path changes for the aluminum alloy AA6016 and the deep drawing steel DC06 is presented. In the first stage of the experimental investigations, yield loci with linear strain paths were considered to characterize the material behavior for the initial condition. On further experiments with several stress states the strain path dependent hardening behavior of the material is determined. The non-linear strain paths are realized through uniaxial prestrained primary specimens with following extraction of secondary samples for following stress states, e.g. a modified ASTM simple shear test specimen. Subsequent yield loci are investigated and compared to the yield surfaces Hill'48 and Barlat 2000 (Yld2000-2d) with an isotropic hardening behavior. With this study the evolution of the yield locus for prestrained specimens is evaluated. The research of the subsequent yield loci for strain path changes serves as basis for further scientific investigations with a view to assess different approaches of isotropic-kinematic hardening models in consideration of the analyzed steel and aluminum sheet metals. © (2013) Trans Tech Publications.
LFT Import::2019-07-29 (1852)
Keywords: Hardening behavior; Simple shear test; Strain path changes; Yield locus evolution

Examination of controlled thermal radiation exchange for the production of tailored properties on press-hardened components - Reihani, Alborz; Heibel, Sebastian; Schweiker, Thomas; Merklein, Marion (Materials Research Proceedings, 2023)
Through the development of furnace technologies and tool concepts, partial press hardening has become an established process in the automotive industry for setting tailored properties on press-hardened components. Tailored properties on press-hardened components offer the potential to improve crash performance as well as to facilitate downstream joining processes and mechanical treatments. One approach to adjust these properties through local pre-cooling is based on a special oven chamber with an integrated masking technology, called TemperBox®. The integrated mask protects the blank locally from incident heat radiation and simultaneously absorbs the blank's own radiation. An important parameter during this process is the pre-cooling time in the TemperBox®. The pre-cooling time can influence the phase transformation and the component properties. Therefore, blanks made of the conventional press hardening steel 22MnB5 AS150 are partially precooled in the TemperBox® for different periods of time and the component properties are investigated on the basis of formed hat profiles. In addition, a simulation approach for calculating the heat radiation exchange with the finite element software LS-Dyna® is shown. Based on the simulative and experimental investigations, it is demonstrated that there is a dependency between pre-cooling time and the components properties.
CRIS-Team Scopus Importer:2023-04-28
Keywords: Heat Treatment; Hot Stamping; Tailored Properties

Examination of the Real Prestressing Conditions of Tooling Systems - Putz, Alexander; Engel, Ulf (ITC 2002, Proceedings of the 6th International Tooling Conference, 2002)
LFT Import::2019-08-05 (1668)

Examinations on Laser Pyrolysis of Preceramic Polymers - Krauß, Hans-Joachim; Otto, Andreas; Motz, G. (LANE 2004, Proceedings of the 4th International Conference on Laser Assisted Net Shape Engineering, 2004)
LFT Import::2019-08-05 (1109)

Examining Hot Crack Susceptibility of Aluminium Laser Welds with Help of FE Simulation - Komlodi, Attila; Merklein, Marion; Otto, Andreas (Proceedings of Modelling and Simulation Workshop, 20.-24.01, Igls, österreich, 2003)
LFT Import::2019-08-05 (972)

Examining the Impact of Intermediate Cooling on Mechanical Properties of 22MnB5 in a Tailored Tempering Process † - Reihani, Alborz; Heibel, Sebastian; Schweiker, Thomas; Merklein, Marion (Journal of Manufacturing and Materials Processing, 2024)
Tailoring the properties of hot-stamped components offers the potential to enhance crash performance while simultaneously improving downstream joining processes. In recent years, an innovative technology suited for achieving tailored properties involving the utilization of a specialized furnace chamber, known as the TemperBox®, has been introduced. Within this chamber, a cooled aluminum mask shields specific areas of the blank from incoming heat radiation and concurrently absorbs the blank’s own radiation. The duration of the heat radiation exchange can influence the diffusion-dependent phase transformation and, consequently, the resulting mechanical properties. Hence, the intermediate cooling duration assumes a pivotal role as a parameter, as is investigated in this study. To examine the effects, specimens of the steel 22MnB5 AS150 are subjected to intermediate cooling of varying durations, followed by forming and partial quenching. The temperature profile of the blank during intermediate cooling prior to forming and quenching is analyzed. Subsequently, the tailored hot-stamped components are assessed for hardness, strength, ductility, and thickness strain. The study reveals that with increasing duration of partial intermediate cooling and targeted radiation exchange, a homogeneous ferritic–pearlitic structure is formed from an austenitic structure. This uniform structure of ferrite and pearlite is reflected in lower hardness and strength values, along with improved ductility. Additionally, this paper introduces a simulation methodology designed to calculate the dynamics of thermal radiation and the kinetics of phase transformation.
CRIS-Team Scopus Importer:2025-02-04
Keywords: heat exchange; heat radiation dynamics; hot stamping; simulation; tailored tempering; view factor

Excimer Laser Micro Texturing of Cold Forging Tool Surfaces - Influence on Tool Life - Geiger, Manfred; Popp, Uwe; Engel, Ulf (CIRP Annals - Manufacturing Technology, 2002)
LFT Import::2019-07-16 (1680)
Keywords: Excimer Laser; Surface; Tribology

Excimer Laser Radiation - A Promising Tool for Microstructuring Ceramics - Geiger, Manfred; Lutz, Norbert; Goller, M. (Lasers in Engineering, 1993)
LFT Import::2019-07-15 (410)

Excimerlaserstrahlbiegen dünner metallischer Folien mit homogener Lichtlinie - Meyer-Pittroff, Frank (Friedrich-Alexander-Universität Erlangen-Nürnberg, 2003)
Thanks to laser technology, forming using thermally induced tensions has found Entrance into micro technology, initially starting from flame straightening in shipbuilding. To realize bendings the Temperature-Gradient-Mechanism can be used. Therefore the compressive stresses induced need to be limited to·surface-near areas of the work piece. Thus, the excimer laser allows the bending of thin metallic foils without the use of any exterior forces. The work illustrates excimer laser beam bending using a homogeneous light line, discusses various analytic models·and describes appearing phenomena, when irradiating at fluences above ablation threshold, within a newly developed descriptive mode

Excimer Laser Texturing of Hard Coated Cold Forging Tools - Investigations on Tool Life - Popp, Uwe; Neudecker, Thomas; Engel, Ulf; Geiger, Manfred (Advanced Technology of Plasticity, Proceedings of the 7th ICTP, 2002)
LFT Import::2019-08-05 (1682)

Excimer Laser Texturing of Tool Surfaces and its Influence on Friction in Cold Forging - Popp, Uwe; Neudecker, Thomas; Engel, Ulf; Geiger, Manfred (Proceedings of the 2nd International Conference THE Coatings in Manufacturing Engineering, 2001)
LFT Import::2019-08-05 (836)

Excimer laser treatment of tool surfaces and its influence on friction in metal forming processes - Neudecker, Thomas; Popp, Uwe; Engel, Ulf (Proceedings of the 1st International Seminar on Progress in Innovative Manufacturing Engineering (PRIME), Sestri Levante, Italien, 2001)
LFT Import::2019-08-05 (837)

Experimental analysis of laser welding of coloured thermoplastics and thermoplastic elastomers - Hopfner, M.; Frick, Thomas; Polster, Steffen; Eßer, Gerd; Gebert, K. (Proceedings of the LANE 2004, 2004)
LFT Import::2019-08-05 (1100)

Experimental analysis of the forming behavior of ash wood veneer with nonwoven backings - Zerbst, David; Affronti, Emanuela; Gereke, Thomas; Buchelt, Beate; Clauß, Sebastian; Merklein, Marion; Cherif, Chokri (European Journal of Wood and Wood Products, 2020)
In the present study, the forming behavior of veneer with nonwoven backings was analyzed. The paper contributes to the lack of data on numerical predictions of the formability of veneers for the manufacturing of automotive trim parts. Tensile and shear tests were carried out at normal climate conditions and after water immersion to obtain material parameters for a transverse isotropic material description. The Tsai Wu failure criterion was applied to the estimation of strength under different stress combinations. Analysis of the directional deep drawing capacity of the veneer laminate was done by the Nakajima test. Stress states from biaxial to uniaxial were induced into the material depending on the geometry of the sample. Strains were evaluated locally until material failure using the digital image correlation method. Major strain was defined in the direction perpendicular to the grain. Increasing major strain was found from biaxial to uniaxial stress states. Highest strain limits were found for wet veneers tested with heated forming tools. Cracks occurred in the early wood zone for all geometries and propagated in the direction parallel to the grain. Generally, the Nakajima test is suitable for the evaluation of the formability of veneer laminate sheets. The presented data and, in general, the suggested experimental program can be used for the development and validation of veneer laminate material models for forming simulations.
CRIS-Team Scopus Importer:2020-02-28

Experimental analysis of the influence of the embossing and upsetting process on joint strength in resistance element welding with upset auxiliary joining elements - Meinhardt, M.; Lechner, Michael; Merklein, Marion (INTERNATIONAL DEEP-DRAWING RESEARCH GROUP CONFERENCE (IDDRG 2021), 2021)
CRIS-Team WoS Importer:2021-11-05

Experimental and analytical investigations on friction stir welding of steel aluminium tailored hybrids - Geiger, Manfred; Merklein, Marion; Giera, Artur; Staud, Detlev (Production Engineering, 2006)
LFT Import::2019-07-16 (1254)

Experimental and Analytic Determination of Forming Limit Curves Applied to a Bainitic Steel - Kuppert, Andreas; Merklein, Marion; Mütze, S. (Proc. of MATFEM Conference 2010, 2010)
LFT Import::2019-08-05 (890)

Experimental and Numerical Analysis of Cold Formed Multi Pin Structures Using a Multi-Acting Tool Design - Römisch, David; Merklein, Marion (12th Tooling Conference and Exhibition Tooling 2022, 2022)
Intelligent material combinations for the production of multi-material systems as well as lightweight construction to save weight are becoming increasingly important in industrial applications. However, the joining process of dissimilar materials poses challenges to established joining processes due to different mechanical properties and chemical incompatibilities and lead to a need for new, versatile joining technologies. The use of cold extruded pins made from the sheet metal plane is the subject of current research due to the added potential for weight saving and the advantage of process-induced work hardening. To produce these pins and especially multi-pin structures, however, new tool concepts are needed. In the present work, a multi-acting tooling design is presented to produce a multi-pin array consisting of a 3x4 matrix by extrusion from the sheet metal plane. The tool allows the punches, the blank holder and the ejector to be controlled independently. The individual pins can be formed both simultaneously in one stroke and sequentially to control the formation of each pin individually. The numerical model utilised for designing the active parts of the tool is used to analyse the complex, resulting material flow and to gain insights into the pin forming. Furthermore, first experimental results of cold extruded multi-pin arrays are presented to obtain a basic scientific understanding of the influence of the tool on the process in combination with the numerical result
Keywords: Multi pin extrusion; Multi pin tool; Joining by forming; Mechanical joining

Experimental and Numerical Analysis of Fatigue of PVD and CVD Coated Steels for Cold Forging Tools - Hinsel, Christian; Engel, Ulf (ICIT’97 Conference Proceedings (Int.Conf.on Industrial Tools, April 21-22,1997 Maribor, Slov) Vol. I, 1997)
None
LFT Import::2019-08-05 (1988)

Experimental and numerical analysis of tribological effective surfaces for forming tools in Sheet-Bulk Metal Forming - Kersting, Petra; Gröbel, Daniel; Merklein, Marion; Peter, Sieczkarek; Wernicke, Sebastian; Tekkaya, A. Erman; Krebs, Eugen; Freiburg, Dennis; Biermann, Dirk; Weikert, Tim; Tremmel, Stephan; Stangier, Dominic; et al. (Production Engineering, 2016)
Sheet-Bulk Metal Forming (SBMF) allows the manufacture of complex parts with integrated functional form elements, such as teeth and thickened areas. Therefore, bulk forming operations are applied to sheets with initial thicknesses of 2 or 3 mm. The design and functionality of the tools are as important as the process itself. Therefore, the working group “Tools” of the Transregional Collaborative Research Centre on Sheet-Bulk Metal Forming (CRC/TR73) focuses on the optimization of the technical tool design. By varying topographies or applying tailored coatings, the friction behavior is changed to achieve a better form filling and to reduce process forces during the forming operations. In this paper, the potential of different tailored surfaces is validated by simulations and experimental studies. The tribological behavior of 14 surface microstructures is evaluated using a half-space model in order to select structures suitable for application. Those were characterized experimentally by ring-compression and pin-extrusion tests. The determined friction factors were used in a forming simulation to predict the form filling of small cavities in a flow forming operation. Furthermore, special attention is paid to the utilization of the anisotropic behavior of specific structures. The results were validated by an incremental gear forming process.
Keywords: Sheet-Bulk Metal Forming; Tailored surfaces; Milling technologies; Coating technologies; Forming simulations; Tribology simulation

Experimental and numerical evaluation of different powder metallurgical steels for cold forging tools - Falk, Bernd; Engel, Ulf; Geiger, Manfred (Advanced Technology of Plasticity 1999, Proc. of the 6th Int. Conf. on Technology of Plasticity, Vol. 1, 1999)
None
LFT Import::2019-08-05 (1997)

Experimental and numerical investigation of a strain rate controlled hydraulic bulge test of sheet metal - Suttner, Sebastian; Merklein, Marion (Journal of Materials Processing Technology, 2016)
LFT Import::2019-07-29 (2185)
Keywords: Constant strain rate; Hydraulic bulge test; Material characterization; Metal forming

Experimental and Numerical Investigation of the Formability of Laser Welded Patchwork Blanks - Lamprecht, Klaus; Geiger, Manfred (Sheet Metal 2005, Proceedings of the 11th International Conference on Sheet Metal; Advanced Materials Research, 2005)
Within the past decades tailored welded blanks have become a key product for the construction of lightweight automotive bodies. Following the principle of applying material only where it is really needed results in an improved stiffness and crash worthiness of the body-in-white, while at the same time weight and production costs may be reduced. An alternative to the concept of tailored blanks is the so-called patchwork blank technique. The principle of patchwork blanks is to add a flat piece of sheet metal onto the main blank in the areas where reinforcements are required. The assembly can be done by adhesive bonding, resistance spot welding or laser welding prior to forming. The major benefits of this technique in comparison to tailored blanks are the abolition of cutting operations and a high flexibility regarding the shape and position of the reinforcement. Even if there is a big application potential for patchwork blanks in automobile production, practical realisation of this innovative technique is hindered due to a lack of knowledge regarding the formability of patchwork blanks. In this study the formability of laser welded patchwork blanks is investigated by means of experimental trials and finite element analysis. In order to simulate accurately the forming processes of patchwork blanks using finite element analysis, knowledge about the characteristics of the weld metal, including the weld bead and the heat affected zone, is essential. Microhardness measurements have been applied to analyse the heat affected zone and to determine its lateral dimensions. The constitutive behaviour of the weld metal has been investigated by uniaxial tensile tests with a special sample geometry. The results obtained from these experimental investigations have been used to define different modelling techniques for the finite element analysis of patchwork blank forming processes. It can be shown that the consideration of the modified material properties along the weld seam leads to an improvement of the accuracy of the numerical calculation.
LFT Import::2019-08-05 (1126)
Keywords: Finite element method; Forming; Patchwork blank

Experimental and Numerical Investigation on a Full Forward Extrusion Process from Metal Strip - Stellin, Tommaso; Merklein, Marion; Engel, Ulf (Proc. 9th Int. Conf. Multi-Material Micro Manufacture, 2012)
LFT Import::2019-08-05 (1844)

Experimental and numerical investigations of the tribological conditions in a cup drawing process - Merklein, Marion; Zöller, Fabian; Sturm, V. (Proc. Int. Deep Drawing Research Group Conf. 2014 (IDDRG 2014), 2014)
LFT Import::2019-08-05 (2012)

Experimental and numerical investigations on a pressure dependent friction model - Zöller, Fabian; Vera, Sturm; Merklein, Marion (Key Engineering Materials, 2015)
The objective of this paper is the investigation of the implemented pressure dependent friction model in the FE simulation program AutoForm. Since the values for the required parameters of this approach are not defined in the actual FE simulation program, this paper contributes to a first definition of these parameters. Therefore, experimental investigations with the cup drawing tests are carried out. With the support of the experimental results regarding the maximum stamping force, the model is calibrated and subsequently validated by the comparison of the sheet thicknesses of the experimental and numerical investigations. The results of this validation reveal a good accordance of simulation and reality in nearly all areas. However there are also areas in which the prediction accuracy decreases in comparison to the basic simulation. Therefore, additional investigations have to be carried out which concentrate on the modification of this pressure dependent approach towards a better universal prediction accuracy of the simulation.
LFT Import::2019-08-05 (2084)
Keywords: Friction; Simulation; Tribology

Experimental and numerical investigations on frictional behaviour under consideration of varying tribological conditions - Merklein, Marion; Zöller, Fabian; Sturm, Vera (Advanced Materials Research, 2014)
In present time the FE-simulation of body parts in sheet metal drawing processes has to be continuously improved to increase the prediction accuracy. The objective of this paper is to describe a methodology to improve the simulation by mapping the complex tribological conditions of the process in the simulation. This methodology focuses on the dependency of influencing parameters on the friction coefficient. The influence respectively the dependency of these factors has been investigated, both in an experiment of a plane strip drawing test and in a FE-simulation of this test. With the sensitivity analysis in the numerical simulation it is possible to compare the implemented COULOMB-friction-model against the experimental results. The results of the experimental and numerical investigation show the need of further investigations on a more geometrical complex test to prove if it is possible to transfer the knowledge and dependencies that has been found in the experiment with the strip drawing test to a more geometrical complex test. © (2014) Trans Tech Publications, Switzerland.
LFT Import::2019-08-05 (1979)
Keywords: Numerical Simulation; Sheet Metal Forming; Tribology

Experimental and Numerical Studies on the Forming Behavior of High Strain Al-Mg-Si(-Cu) Sheet Alloys - Klos, Artur; Kahrimanidis, Alexander; Wortberg, Daniel; Merklein, Marion (Procedia Engineering, 2017)
Al-Mg-Si(-Cu) heat-treatable alloys are characterized by a significant increase in hardness upon ageing compared to 6xxx series alloys with a copper content of Cu<0.15 wt.%. With a higher amount of copper, the formability and ductility of the alloy are typically decreased compared to 6xxx alloys with a low content of Cu. The purpose of this paper is to discuss recent developments of high-strain 6xxx alloys for future automotive applications. The influence of copper content on the forming behavior of Al-Mg-Si(-Cu) sheet alloys was investigated. The examination was confined to four different alloys in total: Three of type AA6111 with varying Cu contents and a reference alloy type AA6016. All alloys were pre-aged at > 80 °C after quenching and had a solute content of Si/Mg ratio in balance (wt.%). The forming behavior was characterized by tensile tests, bending tests, cup drawing tests and Nakajima tests. The experimental results are supplemented by numerical simulation. Hocket-Sherby's hardening law and Hill 90 yield criterion were used for the material modeling behavior. The Marciniak-Kuczynski model (M-K-model) approach was chosen to construct forming limit diagrams for all alloys. The study showed that forming behavior is strongly dependent on the type of alloy, the thickness, and natural aging, which is in turn influenced by the storage period and the quenching rate in sheet production. Up to a Cu content of 0.8 wt.% the limiting drawing ratio is approximately equal to the reference alloy. With contents greater than 0.8wt%, an exponential drop of the formability is observed. Furthermore, the results of the cup drawing tests are compared to the numerical simulations in order to validate the simulation of parts with higher complexity. The results of this work contribute to the application of high strain 6xxx alloys in automotive applications.
CRIS-Team Scopus Importer:2023-03-29
Keywords: AA6016; AA6111; Aluminum; formability