激光拼焊板破裂判据的建立及成形极限预测

为准确判断差厚高强钢激光拼焊板何时、何处发生破裂,在失效行为研究的基础上建立一种新的破裂判据.该破裂判据为:在建立拼焊板左半边成形极限图时,凸模载荷达到最大值时拼焊板发生破裂;在建立拼焊板右半边成形极限图时,拼焊板应变路径向平面应变状态漂移时破裂发生.基于该破裂判据,结合对高强钢拼焊板成形极限试验的仿真,建立其成形极限图.预测结果与试验数据吻合较好,验证了拼焊板破裂判据的正确性和有效性.基于建立的破裂判据,结合对拼焊板成形极限试验的有限元仿真,能够准确、快速获得差厚高强钢激光拼焊板的成形极限图.

Establishment of failure criterion and prediction of forming limit for laser tailor-welded blanks

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.