Proposing an improved cyclic plasticity material model for assessment of multiaxial response of low C-Mn steel

• Validation of current cyclic plasticity material models w.r.t. limited loading cases. • Low C-Mn steel showed Masing behavior with linear shift for uniaxial/ in-phase cases. • Chaboche model under-predicts axial and shear stress for non-proportional (NP) cases. • Chaboche-Tanaka-Meggiolaro (CTM) model results in better predictions for few NP cases. • Proposed modification in CTM model results in improved simulations for all NP cases. Present work is aimed at validation of existing popular cyclic plasticity material models and proposing an improved model for SA 333 Gr. 6 material. Recently reported in-house axial-torsion tests have been used for validation. Present analyses considered Chaboche’s non-linear kinematic hardening rule, Tanaka’s fourth order tensor and Meggiolaro’s non-proportionality considerations. The Chaboche-Tanaka-Meggiolaro model resulted in comparable assessments for stabilized loops under uniaxial, proportional and few non-proportional conditions. However, the axial stress response under most of non-proportional conditions was significantly under-predicted. The proposed modification in dynamic recovery term of kinematic hardening rule resulted in improved assessments for nearly all strain paths.