A finite deformation model for evolving flow anisotropy with distortional hardening including experimental validation

The paper presents a new constitutive model for anisotropic metal plasticity that takes into account the expansion or contraction (isotropic hardening), translation (kinematic hardening) and change of shape (distortional hardening) of the yield surface. The experimentally observed region of high curvature (“nose”) on the yield surface in the loading direction and flattened shape in the reverse loading direction is modeled here by means of the concept of directional distortional hardening. The modeling of directional distortional hardening is accomplished by means of an evolving fourth-order tensor. The applicability of the model is illustrated by fitting experimental subsequent yield surfaces at finite plastic deformation. The simulation results were compared with test data for aluminum low and high work hardening alloys. In this introductory paper we will consider only the proportional loading case.