Numerical study of springback using the split-ring test for an AA5754 aluminum alloy

The split-ring test provides a simple benchmark for correlating springback obtained by finite element analysis (FEA) with experimental measurements. This test consists in cutting a ring specimen from a full drawn cup and then to split the ring longitudinally along a radial plane. The difference between the ring diameters, before and after splitting, gives a direct measure of the springback phenomenon, and indirectly, of the amount of residual stresses in the drawn cup. In this paper, the numerical simulation of the deep drawing process and splitting of an aluminum alloy AA5754-O ring is performed using both the finite element code ABAQUS and the in-house code DD3IMP. The trimming of the ring is carried out with a devoted program, DD3TRIM, which allows the geometrical and material state remapping treatment of solid hexahedral element meshes. The punch-force evolution during deep drawing and thickness distribution obtained numerically are compared with experimental ones provided in [1] (Laurent et al., 2009). The influence of finite element formulation, mesh size and yield criteria on the numerical results for the ring opening is evaluated. The stress distributions in the cup, at the end of the drawing stage are analyzed and some explanations concerning their influence on springback mechanisms are given.