Anisotropic distortional hardening based on deviatoric stress invariants under non-associated flow rule. Part-II: Generalization combined with non-quadratic yield function under associated flow rule

Abstract

To control the curvature of yield loci, a generalized anisotropic distortional hardening ADH (G-ADH) model is established within the framework for Bauschinger effect prediction in ADH2022 (Hu and Yoon, 2022). Any yield criterion can be coupled with G-ADH. The convexity of G-ADH depends on the convexity of the coupled yield criterion. Under the proportional loadings, G-ADH still possesses the characteristics of the coupled yield criterion. In the present work, analytical Poly6-18p and Yld2000-2d yield criteria are coupled with G-ADH to predict the yield loci and R-values under the associated flow rule. Applying G-ADH to SPCC, EDDQ and DP780 materials, the result shows that G-ADH still processes the same ability as ADH2022 to predict the Bauschinger effect, permanent softening & strengthening behavior, and work-hardening stagnation & overshooting behavior. Applying G-ADH to AA6061-O and AA7075-T6, the result shows that G-ADH coupled with analytical Poly6-18p is capable of regulating the curvature of yield loci in pure shear and plane strain stress states, and accurately predicting the complex r-curve and uniaxial tension curve.