Experiment and predictions of strain and stress based failure limits for advanced high strength steel0

Strain based failure measurements are traditionally very popular and implemented to construct the failure limits. The predictions of these measurements through various models were compared and agreed for the conventional steels. Whereas continuous demand on the reduction of the vehicle mass while maintaining comfort and passenger safety for current and future vehicles car manufacturers are attracted to a newly developed advanced high strength steel. These steels that promises high strength and enhanced ductility were produce to reduce the impact of fuel usage by balancing the above demands. However while implementing these steels many challenges were faced by manufacturers and tool designers. One of the challenges is to predict the forming limit diagram through the conventional strain based models. In this paper experiments were performed on Dual Phase and Transformed Induced Plasticity steels to plot the forming limit diagram and further compared with the conventional strain based models. It was observed that strain based model under predicts the failure whereas stress based models are the best agreement with experiments.