Effects of grain interaction on deformation in polycrystals

The deformations of a face-centered cubic polycrystal are simulated under i dealized (plane strain compression) rolling conditions. A polycrystal is co nstructed using 1099 rhombic dodecahedron shaped crystals, each discretized with 48 tetrahedra elements. The rhombic dodecahedron is a 12-sided. space -filling polyhedron and serves as an idealized crystal geometry. The materi al behavior is specified at the level of a single crystal with rate depende nt slip. The numerical formulation maintains compatibility and equilibrium in a weak sense using hybrid finite element methodology. The influence of t he local neighborhood on crystal deformation is examined by conducting a se ries of numerical experiments on the same set of crystals. Each simulation uses a different spatial mapping of orientations to effectively alter the n eighborhood of each crystal, allowing the dependence of deformation on crys tal orientation to be examined. Comparisons are made to earlier results obt ained with brick shaped crystals and to the results obtained with a second polycrystal consisting of 172 crystals with 576 elements in each rhombic do decahedron. Coarse crystal discretizations are adequate for modeling bulk a nisotropic properties, but a detailed investigation of local neighborhood e ffects require a finely discretized mesh that is better able to capture gra dients in the deformation field. (C) 1998 Elsevier Science S.A. All rights reserved.