Inverse Identification of Advanced Yield Criteria Using Cup Drawing and Rensile Tests

Nowadays, the accuracy of forming simulations in automotive industry requires advanced material models having yield loci far more complicated than the conventional ones. The more sophisticated the employed material models are, the more material parameters have to be determined. At present, various mechanical tests under different loading conditions such as bi-axial stretching (hydraulic bulge and compression tests), plane strain, tensile, shear etc. are applied to identify the material parameters of these advanced models. Except for the tensile tests, the mentioned experiments are not only expensive to be performed but they are cumbersome to be evaluated, as well. Furthermore, these experiments are not standardized. The right specimen geometry and the correction of the edge effect are some of the problems that can be encountered while carrying out and evaluating these tests. This paper highlights an alternative inverse-analysis approach to determine the material parameters of the advanced yield loci like Yld2000-2d (Barlat2000) [1]. Both cup drawing, which can be performed at Erichsen machine, and the standard tensile tests for the angles of 0°, 45° and 90° to rolling direction are the essential experiments for the optimization of the parameters via FEM (finite element method). The applicability of the proposed method is investigated by comparing the obtained yield loci with the experimental data, received from tests with different loading conditions.