The effects of anisotropic yield functions and their material parameters on prediction of forming limit diagrams

In this paper, the capability of five different yield functions to predict the forming limit diagram (FLD) of the continuous cast 5754 Aluminum sheet has been compared with focus on the differences in the predicted limit strains based on the method of determining the yield function parameters. The yield functions proposed by Hill (1948, 1990, 1993), Barlat and Lian (1989), and Plunkett et al. (2008) have been considered in this study. The FLDs have been calculated numerically based on the above mentioned yield functions together with the Marciniak-Kuczynski (M-K) approach. Simulations show that the predicted FLDs strongly depend on the method of determining the material parameters (used in the yield functions) and the corresponding shape of the yield surface. Furthermore, simulations show that for biaxial stretching, the shape of the yield surface is the most dominant factor affecting the FLD. (C) 2012 Elsevier Ltd. All rights reserved.