A NEW APPROACH TO IMPROVE MATERIAL MODELS

The inelastic behavior of materials is described most efficiently by u nified models when their material functions are determined so that flo w, hardening, creep etc. will be covered correctly. In this paper, the adaptation of a model is not confined to finding the optimal material parameters but is extended to the identification of the optimal shape of the material functions itself. Material functions given by series of simple shape functions defined in discrete sections which merge smo othly together lead to the best adaptation to experimental results. Fu rthermore, any remaining shortcomings of the model reveal deficiencies in the modelling of the microphysics of the material. Then by careful interpretation of the uncovered physical properties the original mate rial model has to be amended leading to the derivation of even entirel y new models. Thus, a powerful tool is presented here by which a unifi ed model can be checked and improved.