Modeling slip, kink and shear banding in classical and generalized single crystal plasticity

Abstract

Classical crystal plasticity can account for slip, kink and shear band formation in metal single crystals exhibiting a softening behavior. In the case of multiple slip, the stability of symmetric multi-slip configurations depending on the self/latent hardening ratio is investigated. Finite element simulations of symmetric and symmetry-breaking localization modes in single crystals oriented for double slip in tension are presented. Some shortcomings of classical crystal plasticity are then pointed out that can be solved using a Cosserat crystal plasticity model that explicitly takes elastoplastic lattice torsion-curvature into account. The classical theory predicts for instance the same critical hardening modulus for the onset of slip and kink banding. This is not the case any more in generalized crystal plasticity, as shown by a bifurcation analysis and finite element simulations of Cosserat crystals.