Nonlinear Mixed Hardening Constitutive Model Considering Coupling Damage Under Multiaxial Non-proportional Loading Conditions

The Ohno–Wang I model cannot fully characterize the effect of the loading path on the mechanical response of materials. Based on the influence of isotropic hardening and kinematic hardening on the shape and peak stress of hysteresis loop, qualitative analysis and quantitative analysis were used to analyze the mechanical behavior of Q355B under cyclic loading, and the influence of two kinds of hardening on hysteresis loop was determined. The Ohno–Wang I model was improved by coupling the critical value with Benallal & Marquis non-proportional parameters through the analysis of the influence of different components of the kinematic hardening model on the value of back stress and dynamic recovery terms. The relationship between isotropic hardening and kinematic hardening was established by cumulative plastic strain, and a nonlinear mixed hardening constitutive relationship was constructed that characterized the non-proportional hardening phenomenon. In order to reflect the law of mechanical property degradation of materials under cyclic loading, considering the coupling relationship between damage and elastoplastic deformation, a nonlinear mixed hardening constitutive model of coupled damage was constructed. The improved coupling damage constitutive model was realized by UMAT module in ABAQUS, the finite element simulation results had a good correlation with the experimental results.