Identifikation von Interphaseneigenschaften in Nanokompositen

Third party funded individual grant

Project Details

Project leader:
Dr.-Ing. Sebastian Pfaller

Project members:
Wuyang Zhao

Contributing FAU Organisations:
Lehrstuhl für Technische Mechanik

Funding source: DFG-Einzelförderung / Sachbeihilfe (EIN-SBH)
Start date: 01/10/2018
End date: 30/09/2020

Research Fields

Multiscale mechanics
Lehrstuhl für Technische Mechanik
Material Mechanics
Lehrstuhl für Technische Mechanik

Short description (intelligible to all):

In engineering
applications, plastics play an important role and offer new possibilities to
achieve and to adjust a specific material behaviour. They consist of
long-chained polymers and possess, together with additives, an enormous
potential for tailored properties.

techniques have been established to produce and to disperse filler particles
with typical dimensions in the range of nanometers. Even for low volume
contents of filler particles, these so-called nanofillers may have significant
impact on the properties of plastics. This can be most likely traced back to
their very large volume-to-surface ratio. In this context, the polymer-particle
interphase is of vital importance: as revealed by experiments, certain
nanofillers may e.g. increase the fatigue lifetime of plastics by a factor of

The effective
design of such nanocomposites quite frequently requires elaborated mechanical
testing, which might - if available - be substituted or supplemented by
simulations. For this purpose, however, continuum mechanics together with the
Finite Element Method (FE) as the usual tool for engineering applications is
not well-suited since it is not able to capture processes at the molecular
level. Therefore, particle-based techniques such as molecular dynamics (MD)
have to be employed. However, these typically allow only for extremely small
system sizes and simulation times. Thus, a multiscale technique that couples
both approaches is required to enable the simulation of so-called
representative volume elements (RVE) under consideration of atomistic effects.

The goal of this
4-year project is the development of a methodology which yields a
continuum-based description of the material behaviour of the polymer-particle
interphase of nanocomposites, whereby the required constitutive laws are
derived from particle-based simulations. Due to their very small dimensions of
some nanometers, the interphases cannot be accessed directly by experiments and
particle-based simulations must substitute mechanical testing. The recently
developed Capriccio method, designed as a simulation tool to couple MD and FE
descriptions for amorphous systems, will be employed and refined accordingly in
the course of the project.

In the first step, the mechanical
properties of the polymer-particle interphase shall be determined by means of
inverse parameter identification for small systems with one and two
nanoparticles. In the second step, these properties shall be transferred to large
RVEs. With this methodology at hand, various properties as e.g. the particles’
size and shape as well as grafting densities shall be mapped from pure
particle-based considerations to continuum-based descriptions. Further
consideration will then offer prospects to transfer the material description to
applications relevant in engineering and eventually suited for the simulation
of parts.

Last updated on 2019-20-03 at 08:25