Numerical and Experimental Determination of Forming Limit Diagram for DIN 1623 St14 Steel

The prediction of forming limit diagram in industries is one of the most important challenges confronting engineers and researchers. One of the most famous methods in determination of forming limit diagram is Erichsen's cupped test. In this paper, a fully coupled elastic-plastic-damage model based on plane stress elastoplasticity theory was developed and implemented into an explicit code. For evaluation of the model, Erichsen's cupped test was numerically simulated to predict forming limit diagram of DIN 1623 St14 steel. Meanwhile, empirical tests were carried out to determine the forming limit diagram of the material experimentally. Comparison of the numerical and experimental results showed good agreement and adaptation. Hence, it is concluded that finite element method combined with continuum damage mechanics can be used as a reliable and rapid tool to predict the forming limit diagram of sheet metals and is able to reduce the number of costly trials.