Adaptive mesh refinement and automatic remeshing in crystal plasticity finite element simulations
Résumé
In finite element simulations dedicated to the modelling of microstructure evolution, the mesh has to be fine enough to: (i) accurately describe the geometry of the constituents; (ii) capture local strain gradients stemming from the heterogeneity in material properties. In this paper, 3D polycrystalline aggregates are discretized into unstructured meshes and a level set framework is used to represent the grain boundaries. The crystal plasticity finite element method is used to simulate the plastic deformation of these aggregates. A mesh sensitivity analysis based on the deformation energy distribution shows that the predictions are, on average, more sensitive near grain boundaries. An anisotropic mesh refinement strategy based on the level set description is introduced and it is shown that it offers a good compromise between accuracy requirements on the one hand and computation time on the other hand. As the aggregates deform, mesh distortion inevitably occurs and ultimately causes the breakdown of the simulations. An automatic remeshing tool is used to periodically reconstruct the mesh and appropriate transfer of state variables is performed. It is shown that the diffusion related to data transfer is not significant. Finally, remeshing is performed repeatedly in a highly resolved 500 grains polycrystal subjected to about 90% thickness reduction in rolling. The predicted texture is compared with the experimental data and with the predictions of a standard Taylor model.
Mots clés
Adaptive mesh refinement
Anisotropic mesh refinement
Computation time
Crystal plasticity finite element
Crystal plasticity finite element method
Deformation energy
Experimental data
Finite element simulations
Level Set
Level set framework
Local strains
Material property
Mesh distortion
Mesh sensitivity
Microstructure evolutions
Polycrystalline aggregates
Remeshing
State variables
Taylor models
Thickness reduction
Unstructured meshes