Finite element simulations of microbeam bending
Background
Microbeam bending experiments for single crystals of the high temperature alloy IN718 have been initiated at Dept Applied Physics, Chalmers, see figures below. The purpose of these experiments is to understand the physical deformation processes in a grain and their influence on the macroscopic engineering behavior of the material. To obtain the macroscopic behavior, computational homogenization of grain structure models are performed. One key component in this homogenization is the material model for single grains. The standard choice of such a model is crystal plasticity where the crystallographic directions of the grain are explicitly taken into account.
Bending of microbeam with length »20µm (left) and resulting force-displacement (right).
Goal
The goal of the current project is to establish a procedure how to identify material parameters of a crystal plasticity model based on finite element simulations of microbeam bending. To achieve this a user material model UMAT (in Abaqus) of crystal plasticity must be implemented and a material parameter identification must be done by coupling an optimization algorithm with the finite element code. Furthermore, since each individual beam has its own geometry the finite element model in Abaqus of the microbeam should be parametrized.
Main steps in the project
· Finite element model of microbeams. Use Python script to build a model based on an individual geometry.
· User material model UMAT in Abaqus of crystal plasticity. Based on available implementation adapt model to Abaqus.
· Parameter identification. Couple optimization code (either Matlab or Python) with Abaqus.
· Study behavior of different microbeam geometries and compare with experimental data.
Preliminary project plan
Week 1-3: Literature study, Python scripting and Abaqus
Week 4-6: Crystal plasticity model
Week 7-13: Parameter identification
Week 14-16: FE simulations of different beam geometries and crystallographic directions
Weel 17-: Report writing
Student background
This project is suitable for preferably a student with an interest in computational material mechanics and the finite element method. The project will give you a deep understanding of how existing commercial finite element codes work. At the same time the project and its result will be part of current research at the Division of Material and Computational Mechanics and at Applied Physics.
Supervisors: The master thesis is a joint project between Department of Applied Mechanics and Applied Physics. The supervisors are Magnus Ekh () and Magnus Colliander ().