A UNIFIED APPROACH FOR PARAMETER-IDENTIFICATION OF INELASTIC MATERIALMODELS IN THE FRAME OF THE FINITE-ELEMENT METHOD

This work is concerned with identification of parameters for inelastic material models. In order to account for possible non uniformness of stress and strain distributions, the identification is performed in th e frame of the finite element method. In particular, linearization pro cedures are described in a systematic manner for he case of complex ma terial models within a geometric linear theory. This unified approach allows one to apply the Newton method for solving the associated direc t problem and to apply gradient based methods for solving the associat ed inverse problem, which is considered as an optimization problem. Tw o numerical examples demonstrate the versatility of our approach: firs tly, we consider Cooks membrane problem based on simulated data for re -identification of material parameters for a viscoplastic power law. F urthermore, material data for J(2)-flow theory are determined, based o n experimental data obtained by a grating method for a compact specime n, and we will investigate the results by using different starting val ues and stochastic perturbation of the experimental data.