Authors: Walid Hammami Laurent Delannay Anne Marie Habraken Laurent Duchêne
Publish Date: 2009/12/15
Volume: 2, Issue: 1, Pages: 65-
Abstract
The MULTISITE model 1 is based on polycrystalline plasticity and the underlying hypotheses of the model are i that the deformation of each grain is significantly influenced by the interaction with a limited number of adjacent grains and ii that local strains deviate from their macroscopic average according to specific “relaxation modes” The LAMEL model 2 is reformulated into the more general elasticviscoplastic MULTISITE model permitting various relaxation modes This model has been validated for cubic materials but hexagonal closepacked HCP crystals usually demonstrate larger anisotropy than cubic crystals The model was used to simulate uniaxial tensile tests performed on rolled sheets made of Ti6Al4V The Lankford coefficients r calculated in various directions in the plane of the sheet were analysed In this study different grain interaction hypotheses were tested Besides it appeared that the value of the critical resolved shear stresses CRSS of the different slip system families of the HCP metal had significant effects on the results Their influence as well as the influence of the strain rate sensitivity parameter was examined
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