Failure analysis of DP600 steel during the cross-die test

Dual-phase (DP) steels are suitable candidates for automotive application due to their high strength and high initial work hardening rate. The forming characteristics and failure behaviour of DP steels, which show ductile behaviour with a dimpled fracture surface, have been the point of focus of different researchers. In the current work, the Gurson–Tvergaard–Needleman (GTN) model is utilised to predict the failure behaviour of DP600 steel during the cross-die test, which has been used extensively in the automotive industry to assess the formability of sheet metals. GTN model parameters were identified through the response surface methodology (RSM), and were verified by the comparison of predicted and experimental forming limit curves (FLCs). The good agreement between the simulation and experimental results concerning failure behaviour during the cross-die test indicates that the GTN model can be applied to predict the forming characteristics of DP600 steel. It was also concluded that RSM is a proper method of predicting GTN model parameters.

► Failure behaviour of DP600 steel during Nakazima and cross-die tests was simulated. ► Since DP600 steel shows ductile behaviour, the GTN model was applied for analyses. ► Relevant GTN model parameters for DP600 steel were identified utilising RSM.