A Description of Creep Anisotropy Induced by Plastic Pre-strain : 2nd Report, A Form Based on a Mapped Effective Stress

Abstract

A mapped (effective) stress defined by a linear transformation of four rank was applied to formulate an anisotropic creep constitutive equation. First, a reduced version of the polynomial representation of isotropic strain rate function was discussed in connection with an effective stress mapped by a four-rank anisotropic tensor. Then, a rational effective stress defined by the four-rank anisotropic tensor proposed by Baltov-Sawczuk was examined, and it was extended so as to incorporate both isotropic and anisotropic hardenings. By using the proposed anisotropic effective stress tensor, a form of anisotropic creep constitutive relation was develpoed and embodied by using the functional form of Bailey-Norton creep law. The proposed model was applied to the anisotropic creep behavior after plastic deformation for 316 stainless steel at elevated temperature. A comparison between the predicted and experimental results showed reasonable agreement.