A plastic constitutive model for anisotropic hardening metals

摘要

Simplified anisotropic plastic constitutive equations for initially anisotropic metals are developed. After multiple-prestraining the initially anisotropic metals, were various plastic behaviors investigated experimentally by the author. The new constitutive model is based on numerous experimental facts and it contains new evolutionary rules for the outer/bounding surface based on the two-surface concept. Benchmark tests were performed to estimate the applicability of the new model compared to the two-surface constitutive models of isotropic/mixed hardening under combined axial and torsional stresses. The new model is expressed in the five dimensional deviatoric stress space and the directions of the principal axes of the anisotropic hardening outer surface are fixed. The model is not useful for a precise discussion on general anisotropies and on evolutionary changes including rotations of the principal axes, but it is comparatively simple and easy to apply to discuss evolutionary changes in the anisotropies due to multiple preloadings.