Abstract：In order to predict when and where the rupture of multi-gauge high strength steel of laser tailor-welded blanks （LTWB） happens, new failure criteria are proposed based on the research of failure behavior. In the established criteria, for the left side of forming limit diagram, LTWB ruptures when the punch load achieves maximum; for the right side of forming limit diagram, rupture happens when the strain path drifts to plane strain state. On the basis of the failure criteria, combined with the FE simulation of forming limit test, the forming limit diagram （FLD） of high strength steel LTWB is established. Good correlation between simulation and experimental results is obtained, which also verifies the validity and reliability of the failure criteria. By combining the failure criteria with FEM, the FLD of multi-gauge high strength steel LTWB can be calculated accurately and conveniently.
2008, Vol. 29 
