Simulated Planar Polycrystalls With Planar and Spatial Random Lattice Orientations

A planar multiscale model of a polycrystalline aggregate was employed in this paper to arrive at new and interesting results. The model accounted for the most important mesoscopic features including explicitly modeled random grain structure with crystal grains represented as randomly oriented monocrystals obeying anisotropic elasticity and crystal plasticity (Schmid resolved shear stress) constitutive models. The results presented include the illustrative description of simulated mesoscopic strain fields, including the development of shear bands, and a sensitivity analysis of the equivalent macroscopic response at various sizes of polycristalls smaller than Representative Volume Element (RVE). Columnar grain structure is assumed in a planar (plane strain) finite element model. The presentation of results includes the comparison of aggregate responses obtained assuming 2-D only and full 3-D random grain orientations. The material properties have been chosen to represent the German nuclear reactor pressure vessel steel 22 NiMoCr 3 7.