Crystal-Plasticity FEM Study on Effects of Simplified Grain Representation and Mesh Types on Mesoscopic Plasticity Heterogeneities (Postprint).

摘要

A numerical study using crystal plasticity finite element method was performed in order to investigate the influence of the grain boundary morphology (stair-case or smooth/flat) and the selection of different mesh types (hexahedral and tetrahedral meshes) on the distribution of simulated plasticity heterogeneities. A bicrystal (a hard grain and a soft grain) sphere embedded in a cubic grain was utilized to perform the current numerical study. The volume averaged responses for the simulated plasticity values (von Mises stress, total accumulated slip system shear and maximum accumulated slip system shear) showed no significant dependence on the grain boundary representation and mesh type. However, the bicrystal represented by uniform hexahedral meshes with staircase grain boundaries tends to show more extreme local plasticity values (in the head and tail of the distribution), particularly populated in the grain boundary region. Differences in local plasticity values between the stair-case and the smooth (or flat) grain boundary cases and between the hexahedral and the tetrahedral mesh cases were largest in the grain boundary region, and the degree of the differences depended upon the plasticity susceptibility of the grain. The simulation results suggest that the grain boundary represented by the stair-case morphology can be a source and/or a sink for local extreme plasticity, compared to the grain boundary represented by the smooth (or flat) morphology.