应用韧性断裂准则预测盒形件拉深成形极限

目前已提出的韧性断裂准则预测板料成形极限，只在简单轴对称件中得到应用．利用作者提出的韧性断裂准则预测了铝合金板LF21，LY21(M)和钢板st17非轴对称的方盒件拉深成形极限，并与成形极限图的预测结果和实验结果进行比较．结果表明，这种方法较好地预测了盒形件拉深成形极限，为预测非轴对称件成形的断裂发生提供了一种有效的方法，也为预测复杂形状零件成形极限奠定了基础．

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.