Effect of Yield Function on the Stamping Springback of Aluminum Alloy

The springback of aluminum alloy sheet after stamping is much larger than that of the steel sheet of the same strength. This is one of the reasons for the aluminum alloy sheets not yet being widely used in stamping automobile parts. The quality of springback prediction for a sheet metal forming process depends on a precise material model. In this paper, an A-pillar was selected as an example to investigate the effect of yield function (Hill’48, Barlat89 and Barlat2000) on the predicted springback of automotive parts pressed from the 5754 aluminum alloy sheet. A finite element model was established using commercial stamping software PAMSTAMP2G. The parameters of the material models were derived from the uniaxial and biaxial tensile tests. The stamping experiments of A-pillar were carried out to obtain the springback values of actual parts. The springback values of the stamped parts were measured by the 3D scanning technology. The comparison between the predicted values and experimental ones shows that the predicted springback using the Barlat2000 yield function is the best.