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

Three-dimensional finite element computations are performed on cubes made o f several hundreds of grains. The local behaviour in each grain is represen ted by a crystallographic model. This approach allows us to compare the mat erial response at different scales. A macroscopic stress-strain curve can b e derived from the force-displacement response of the mesh. On the other ha nd, all the grains having the same crystallographic orientation can be take n in a unique phase, and the average response can be compared with models a ssuming uniform stresses/strains in each phase. Considering each grain indi vidually allows us to characterise the effect of the surrounding grains. Fi nally, an analysis of the results inside the grains provides information ab out the relative contributions of the core of the grain and the grain bound ary to the deformation/hardening process. The results obtained at the diffe rent scales are compared for various types of geometries, assuming either t hat the cube is in the material or that one or several faces are free surfa ces. (C) 1999 Elsevier Science B.V. All rights reserved.