A Centroidal Voronoi Tessellation Based Approach for Creating Grain Morphology for Crystal Plasticity Finite Element Simulations

A simple approach based on centroidal Voronoi tessellation (CVT) is proposed here to create three-dimensional microstructures, for crystal plasticity finite element (CPFE) simulations. In the proposed approach, the grain morphology for any given specimen geometry is created with a predetermined grain size. Instead of using the conventional way that generates the Voronoi cells first and then meshes them into finite elements, this new approach discretises the pre-meshed specimen with the grain seeds generated by the CVT method. This new technique prevents the presence of high density mesh at the vertices of Voronoi cells, and can tessellate arbitrary geometry much more easily. Using a grain aspect scaling algorithm, the proposed approach can create any arbitrary microstructure with a given grain size and aspect ratio. Examples for non-equiaxed polycrystals with different element types are shown. Specimens with irregular shapes and voids are tessellated using this new approach. The grain aspect scaling algorithm is not limited to CVT but can be used with arbitrary grain seeds, offering great flexibility to model diverse material morphologies. It is shown that this proposed approach is simple and efficient.