Interpretation of the behavior of metals under large plastic shear deformations: A macroscopic approach

Abstract

In this paper, we attempt to simulate and interpret the behavior of metals under large plastic shear deformation involving reversal of the shearing direction in detail by a macroscopic approach. First, a model in the form of viscoplasticity, in which an anisotropic yield surface concept is coupled with a plastic spin concept, is provided. The plastic spin formulation used here is based on the concept of the noncoaxiality between the stress and the plastic rate of deformation. It is, for the first time, coupled with the concept of anisotropic yield surface. Next, simulations of free-end shear and simple shear are performed. Effects of anisotropy and spin tensors are examined. It is emphasized that the plastic spin associated with the anisotropic flow rule plays a key role in the successful simulations of the reverse shearing behavior. The present model with the plastic spin also succeeds in reproducing the behavior during cyclic shear deformations. It is concluded that the large strain behavior of metals during reverse and cyclic shear deformations can be well simulated and reasonably interpreted by the very simple anisotropic model with the simple relation for the plastic spin.