Modeling of Yield Surfaces for A5052 Aluminum Alloy Sheets with Different Tempers by Simplified Identification Method and Its Experimental Validation

Yield surfaces of A5052 aluminum alloy sheets with different tempers are modeled by the simplified identification method using the circumscribing polygon. In this method, a polygon circumscribing the equal plastic work contour is determined by uniaxial tensile, equal biaxial tensile and plane strain tensile tests. Anisotropic yield surfaces of A5052 aluminum alloy sheet are modeled by Yld2000-2d (Barlat et al., 2003) and Yld2004-18p (Barlat et al., 2005) yield functions. Both yield functions can express the inscribed curves of the polygons. The modeled yield surfaces of A5052-O agree with the stress points of the equal plastic work contours measured by the reliable bi-axial tensile tests. The proposed method to identify the yield function is effective for aluminum sheet metal. On the other hand, the two identified yield functions show different in-plane plastic anisotropy in the tension-compression combined stress state. To examine the suitability of identified models, the experiments and numerical analyses of the deep drawing tests are carried out. Comparing the experimental and analyzed results, the predicted ear height of drawn cup using the Yld2004-18p yield function agree with experimental results qualitatively. But the prediction of the ear using the Yld2000-2d cannot express the tendency of the experimental one.