On determination of material parameters in cyclic plasticity

In this study, the popular Chaboche-Rousselier elastoplastic constitutive equation is analyzed. Special attention is paid to the material parameter evaluation problem. Several model formulations for DP1000 steel have been calibrated. The influence of the step size assumed for the numerical computations on the solution of the parameter identification problem is demonstrated. Furthermore, it is shown that careful analysis of the model equations leads to derivation of several constraint conditions on the material parameter values. Application of these conditions during the material parameter identification process results in simplification of the elast squares optimization task. Moreover, a new material parameter identification algorithm and a generalization of another one, previously proposed in the literature, are presented. The new algorithm is based on the analytically derived uniaxial process equations. The two aforementioned algorithms are compared with other identification methods, in particular with those utilizing the radial return mapping algorithm.