Session Details

10:30
Stochastic modelling of microstructures for virtual material design (Keynote)
Claudia Redenbach (University of Kaiserslautern)

Kurzfassung:
Macroscopic properties of materials, e.g. the permeability of a filter or the mechanical strength of a fiber composite, are highly influenced by the microstructure. Models from stochastic geometry are valuable tools for studying these relations as they allow for the generation of virtual microstructures with controlled characteristics. The talk presents models for different material classes and explains how to fit the models based on geometric characteristics estimated from 3D image data.

11:10
Fiber-Orientation-Evolution Models for Compression Molding of Fiber Reinforced Polymers
Róbert Bertóti (Karlsruhe Institute of Technology (KIT)), Thomas Böhlke (Karlsruhe Institute of Technology (KIT))

Kurzfassung:
This presentation gives a short review on the Fiber-Orientation-Evolution models commonly used in commercial softwares. The basis of the considered models is Jeffery’s equation from 1922 which describes the motion of a single ellipsoidal particle in a Newtonian fluid. The later models extend Jeffery’s equation for many fiber system, with the use of Fiber-Orientation-Tensors. Models are discussed up to the o-iARD-RPR model (Tseng 2016), and compared considering representative flow modes.

11:30
Effective meso properties for fibre reinforced polymer curing
Christian Dammann (Paderborn University), Rolf Mahnken (Paderborn University), Peter Lenz (Paderborn University)

Kurzfassung:
Our work presents volumetric effective properties in dependence on the degree of cure. They are obtained by homogenization for a representative unit cell on the heterogeneous microscale. To this end, analytical solutions for (n)- and (n + 1)-layered composite sphere models are derived. In a numerical study it is demonstrated that the effective properties lie within certain bounds. Moreover, application of the effective properties to the curing of fibre reinforced polymers is investigated.

11:50
A micro-mechanically motivated approach for modelling the oxidative ageing process of elastomers
Darcy Beurle (Leibniz Universität Hannover), Markus André (University of Applied Sciences and Arts Hannover), Udo Nackenhorst (Leibniz Universität Hannover)

Kurzfassung:
The response of elastomers is strongly influenced by chemical ageing, which changes the polymer network through chain scission and formation of new links. In this work, a micro-mechanical approach based on chain statistics is used to introduce ageing into the constitutive model through a unit-sphere homogenization technique. As a first step, chain scission is handled by a modification of the underlying probabilistic model, and challenges of modelling a secondary network formation are discussed.

12:10
Rheology of Additive Manufacturing Processes for Medical Silicone
Philipp Hartmann (Leibniz Universität Hannover), Christian Weißenfels (Leibniz Universität Hannover), Peter Wriggers (Leibniz Universität Hannover)

Kurzfassung:
The objective of this project is to simulate the 3D-printing of medical grade silicone to support patient specific implant development. This requires the formulation of a thermodynamically consistent finite strain curing model, whereby a multiphysics approach for the mechanical, thermal and chemical fields is necessary. Due to the complexities of the manufacturing process, the Optimal Transportation Meshfree method is used to obtain a numerical solution.