Aluminium sheet forming simulations: influence of the yield surface

The accuracy of simulations of the plastic deformation of sheet metal depend to a large extend on the description of the yield surface, the hardening and the friction. In this paper simulations of deep drawing of an AlMg alloy with a shell model are presented. The yield surface is described by a Von Mises, a Hill ’48 and a Vegter yield function. The parameters for the model are based on biaxial experiments. It is concluded that the shape of the yield locus has a minor influence on the prediction of the punch force–displacement diagram and a large influence on the prediction of the thickness strains. The Vegter model performs much better than the Hill ’48 model, based on the same R-values