Slip-plane plasticity using the theory of material evolution

Abstract

The theory of material evolution is used to model anisotropic plasticity. As suggested by the physics of plasticity, whereby the motion of dislocations yields relative slipping along a particular material plane, a shear-like isochoric material deformation is assumed as the admissible kinematic evolution variable, which is constitutively driven by the thermodynamically dual Mandel stress. A simple and intuitive anisotropic evolution law is considered, where slipping is permitted along a fixed material plane which is prescribed as part of the evolution law. An additional yield criterion is proposed to complete the model. It is demonstrated that the anisotropy of the evolution law renders perfect plasticity, hardening or softening and is rate dependent.