Ratcheting of 304 stainless steel under multiaxial step-loading conditions

摘要

The present study predicts ratcheting response of 304 tubular stainless steel samples undergoing multiaxial step-loading histories by means of nonlinear kinematic hardening rules of Ohno-Wang (O-W), Chen-Jiao-Kim (C-J-K) and the modified rule on the basis of Ahmadzadeh-Varvani (A-V) model. The plastic strain increment, d (epsilon) over bar (p), and the backstress unity vector (a) over bar/vertical bar(a) over bar vertical bar as components in the MaCaulay brackets enabled the modified rule to track different ratcheting directions over multiaxial loading. Term (2 - (n) over bar . (a) over bar/vertical bar(a) over bar vertical bar) further regulated coefficient gamma(2) to account the effect of non-proportionality. The modified rule held term to prevent the model experiencing plastic shakedown.