Department of Micromechanical and Macroscopic Modelling
The chair of Micromechanical and Macroscopic Modelling offers the following student projects. The precise topic and the duration of the project will be defined according to the type of student project, i.e. either project work or Bachelor or Master thesis. Please contact the named advisor or Prof. Alexander Hartmaier for further details.
Der Lehrstuhl Werkstoffmechanik bietet folgende Themen für Studierende an. Die genaue Thematik und der Arbeitsaufwand werden angepasst, je nachdem ob das Thema als Studien-, Projekt-, Bachelor- oder Masterarbeit behandelt werden soll. Bei Interesse nehmen Sie bitte mit dem genannten Betreuer oder mit Prof. Alexander Hartmaier Kontakt auf.
Currently, student projects are only available upon request, for more information please contact Prof. Alexander Hartmaier
Project Work/Master Thesis: Prediction of fatigue crack initiation life using micromechanical modeling and machine learning algorithm (Prof. Alexander Hartmaier, Dr.-Ing. Hamad ul Hassan)In the scope of this work, a framework will be developed to apply the crystal plasticity finite element modeling together with the machine learning algorithms. First of all, the micromechanical modeling of fatigue will be carried out using the finite element modeling at the microstructural level. Crystal plasticity will be used to define the material behavior. A number of synthetic microstructures will be generated and tested to determine the fatigue crack initiation life. This microstructural data will be used to train different machine learning algorithms like Support Vector Machine, Random Forest, Artificial Neural Networks etc. The main aim is to determine and analyze the influence of different microstructural parameters on the fatigue crack initiation life.
Project Work/Master Thesis: Numerical implementation of microstructural wear (Prof. Alexander Hartmaier, Dr.-Ing. Hamad ul Hassan)In the scope of this work microstructural wear will be simulated. First of all the parameters for the Johnson Cook damage model will be determined based on the experimental data from the literature for a scratch test. These parameters will be used to simulate the wear mechanism (using Continuum/SPH modeling).
Master Thesis: Atomistic simulations of the mechanical behaviour of interfaces (Dr. Rebecca Janisch, Prof. Alexander Hartmaier)The group „mechanical properties of interfaces“ is investigating the atomistic origins of interface-related processes during deformation and fracture with molecular dynamics simulations or ab initio DFT-based calculations. Ongoing projects focus on segregation and embrittlement effects at grain boundaries in steel, the deformation mechanisms at interfaces in fcc metals, as well as size effects in lamellar structures. Topics for a student project or master thesis are available upon request.
Master Thesis: Training artificial neural networks by micromechanical crystal-plasticity finite element simulations (Dr.-Ing. Napat Vajragupta, Prof. Alexander Hartmaier)The objective of this study is to train artificial neural networks (ANN) with results of crystal-plasticity finite element simulations of microstructural models. Within this so-called micromechanical approach, the mechanical response of a representative volume element, mimicking realistic microstructures of polycrystals, is calculated by finite element simulations. The plastic behavior of each grain within the microstructure is described by a nonlocal crystal plasticity model. The results of such simulations for various loading conditions describe the macroscopic mechanical behavior of a material. Within this study, it will be investigated how efficiently ANN can be trained to describe macroscopic material behavior for different microstructures.
Master Thesis: Multiscale modeling approach to parameterize the load-path dependent flow rule of DC06 steel (Dr.-Ing. Napat Vajragupta, Prof. Alexander Hartmaier)This study aims at using the micromechanical approach to parameterize a load-path dependent flow rule for DC06 steel. From on the microstructure characterization, the RVE mimicking the real microstructure will be generated. In the second step, the nonlocal crystal plasticity parameters of DC06 steel will be determined by comparing results from RVE simulations with experiments. In the third step, the load-path dependent flow rule will be parameterized by an optimization algorithm, which makes use of virtual experiments (RVE simulations at various loading condition) as input data. Finally, the obtained parameters will be used in metal forming simulations.
Project Work: Influence of crystal plasticity parameters on simulation of nanoindentation test and micro-compression test (Dr.-Ing. Napat Vajragupta, Prof. Alexander Hartmaier)The objective of this study is to study the influence of nonlocal crystal plasticity parameters on the well-known microscopic mechanical tests. First, the influence of these parameters on indentation pile-up profiles along with the load-depth response will be studied. Afterwards, a parametric study on the micro-compression test will be done as well.
Master Thesis: Implementation and parallelization of a nonlocal crystal plasticity model in the framework of FEM model (Dr.-Ing. Napat Vajragupta, Prof. Alexander Hartmaier)Because of the economic limitation, application of open source FEM software to solve complex multiscale materials simulation problem becomes more appealing. Therefore, the objective of this master thesis is to implement a nonlocal crystal plasticity model on an open source FEM software (‚Dealii‘). Within the scope of this thesis, several tasks must be completed within the thesis period include:
- Development of script for converting the ABAQUS model to be compatible with the working environment of Dealli and applying periodic boundary conditions.
- Implementation of a nonlocal crystal plasticity model which has been derived via a user-defined materials subroutine on Dealii by constructing a suitable interface between C++ and Fortran.
- Validation of simulation results by comparing with existing benchmark problems.
- Parallelization and testing the capabilities of UMAT.
To begin the thesis, following knowledges are recommended,
- A good command of C++ and basic in Fortran
- Basic knowledge on the finite element method
- Message Passing Interface (MPI)
As this master thesis is considerably complex, a student will be closely supervised by expertise and student initiatives are welcome.
Master thesis: Inverse method for determining the flow curve of steels from indentation tests (Dr.-Ing. Napat Vajragupta, Prof. Alexander Hartmaier)This master thesis which is a collaboration with Imprintec (https://imprintec.de) aims at improving the inverse method for determining the flow curve of several steel grades from indentation tests. In the first step, flow curves of various steel grades obtained from the inverse method with results obtained from the typical tensile test. As this inverse method is based on interpolation and extrapolation of the existing database, the student shall systematically analyze trends and important factors which can improve prediction accuracy. Furthermore, since this materials database is constructed using the optimization algorithm which adapts materials parameters of the finite element model to fit experimental results, another task within the scope of this thesis will also to improve the optimization scheme as well. It is recommended that the student should have experience on finite element method and a good programming skill.
Project work/Case study/Bachelorarbeit: Implementation of methods for determining elastic properties of steels from the indentation test
(Dr.-Ing. Napat Vajragupta, Prof. Alexander Hartmaier)This research topic which is a collaboration with Imprintec (https://imprintec.de) aims at implementation of existing methods for determining elastic properties of steels from the indentation test into the operating software of the indentation instrument. In the first step, the student shall review literatures and analyze both advantages and disadvantages of each method. Afterwards, the selected methods shall be implemented into the actual operating software and validated with results obtained from the tensile test. For this research work, the student should possess a good programming skill.