轨道车辆大型结构件焊接变形及残余应力有限元分析

Finite element analysis of welding deformation and residual stress in large structure of railway vehicles

采用热弹塑性有限元方法对轨道车辆大型结构端墙部件焊接过程进行了数值模拟,并对其焊接变形和残余应力计算结果进行了分析。结果表明,端墙整体焊接变形较小,上顶板和端墙板部件边缘位置由于结构约束相对较小而出现较大变形,最大变形量在2.88 mm左右。门立柱、端墙板与横梁连接位置焊缝分布密集且有交错,相邻焊缝相互影响,导致残余应力分布状态复杂,且高应力(150~180 MPa)分布范围较广。沿垂直焊缝中心方向提取残余应力路程曲线发现,在高应力区,两端的应力水平略高于中间位置。这是由于两端的熔合线位置受到比中间熔池区更大的约束,导致了更高的残余应力。最后将模拟结果与试验测量值进行了对比,发现两者吻合良好,从而验证了所建立有限元模型的准确性。

A thermo-elastic-plastic finite element method was used to simulate welding process of large structure end wall of railway vehicle,and computational results of residual stress and welding deformation were analyzed.The results indicate that the total value of welding deformation in the end wall is relatively small,while larger deformation appears at the edge positions of the upper roof and wall panel components due to the relatively small structural constraints,which maximizes around 2.88 mm.Welds in the connection position among door column,end wall plate and cross beam are densely distributed and staggered,and adjacent welds affect each other,which results in complex distribution of residual stress with a wide-distributed range of high stress(150~180 MPa).The residual stress path curve extracted in the vertical weld center direction shows that,in the high stress zone,the stress level at both ends is slightly higher than that at the middle position.This is because the fusion line position at either end is more constrained than that at the middle weld pool area,which results in higher residual stress.Finally,the simulation results are compared with the experiment measured values,and it is found that they are in good agreement,which verifies the accuracy of the model.