Assessment of crystal plasticity based calculation of the lattice spin of polycrystalline metals for FE implementation

When texture is incorporated in the finite element simulation of a metal fo rming process. much computer time can be saved by replacing continuous text ure and corresponding yield locus updates by intermittent updates after str ain intervals of e.g. 20%. The hypothesis that the evolution of the anisotr opic properties of a polycrystalline material during such finite interval o f plastic deformation can be modelled by just rotating the initial texture instead of continuously updating it by means of a polycrystal deformation m odel is tested in this work. Two spins for rotating the frame have been ass essed. the classical rigid body spin and a crystal plasticity based "Mandel spin" (calculated from the rotated initial texture) which is the average o f the spins of all the crystal lattices of the polycrystal. Each of these m ethods was used to study the evolution of the yield locus and the r-value d istribution during the 20% strain interval. The results were compared to th ose obtained by simulating the texture evolution continuously using a polyc rystal deformation model. When the texture was nor updated during deformati on, it was found that for most initial textures the Mandel spin does not pe rform better than the rigid body spin, except For some special initial text ures for which the Mandel spin is much better. The latter ones are textures which are almost stable for the corresponding strain mode. When the textur e was updated after each strain interval of e.g. 20% the Mandel spin perfor med much better than the rigid body spin. (C) 2001 Elsevier Science Ltd. Al l rights reserved.