Effect of the Choice of Data Used for Analytical Identification of Orthotropic Criteria for Aluminum Extrusions

Recently, Cazacu [1] derived the expression in terms of stress invariants of the Yld91 yield function [2]. This enables the determination of the anisotropy coefficients analytically and makes possible the investigation of the influence of the data subset used for identification on the predictions. In this paper, we conduct such a study for AA 7079 extrusion. It is shown that if Yld91 and respectively Hill’s parameters are obtained analytically using the same data subset, similar predictions of the anisotropy in uniaxial tension are obtained. However, there are distinct differences in terms of the predicted yield surface evolution with the level of shear.