The application of a ductile fracture criterion to the prediction of the forming limit in quadrate-cup deep drawing

At present, some ductile fracture criteria are applied only to predict the forming limit in stamping forming of simple axisymmetric part. The forming limits in non-axisymmetric square-cup deep drawing of aluminum alloy LF21, LY21(M) and steel st17 are predicted by means of the ductile fracture criterion (DFC) advanced by the author. Comparison of the results predicted by DFC with the results predicted by forming limit diagram (FLD) and the experimental values shows that the present approach can successfully predict the forming limits in square-cup deep drawing,which offers an effective method of predicting the initiation of fracture in non-axisymmetric part forming, and lays a foundation of predicting forming limit of complex shape stamping part.