FE simulation of macro-, meso- and micro-scales in polycrystalline plasticity

Abstract

Three-dimensional finite element computations are performed on cubes made of several hundreds of grains. The local behaviour in each grain is represented by a crystallographic model. This approach allows us to compare the material response at different scales. A macroscopic stress–strain curve can be derived from the force–displacement response of the mesh. On the other hand, all the grains having the same crystallographic orientation can be taken in a unique phase, and the average response can be compared with models assuming uniform stresses/strains in each phase. Considering each grain individually allows us to characterise the effect of the surrounding grains. Finally, an analysis of the results inside the grains provides information about the relative contributions of the core of the grain and the grain boundary to the deformation/hardening process. The results obtained at the different scales are compared for various types of geometries, assuming either that the cube is in the material or that one or several faces are free surfaces.