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

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.