摘要：Four different welding sequences of double-pulse MIG welding were conducted for 6061-T6 aluminum alloy automobile bumpers by using nonlinear elastoplasticity finite element method based on ABAQUS *** post-welding residual stress and deformation were definitely different among the four welding *** results showed that the highest temperature in Solution A was approximately 200℃higher than the melting point of base *** residual stress was resulted from this large temperature gradient and mainly concentrated on the welding vicinity between beam and crash *** welding deformation primarily occurred in both of the contraction of two-ends of the beam and the self-contraction of crash *** with other welding sequences,the residual stress in Solution A was the smallest,whereas the welding deformation was the ***,the optimal sequence was Solution B because of the effective reduction of residual stress and good assembly requirements.

摘要：A three-dimensional finite element approach based on ABAQUS code was developed to investigate the effect of welding sequence on welding residual stress distribution in a thin-walled 6061 aluminum alloy structure. To obtain sound numerical results, the therrno-mechanical behaviour was simulated using a direct-coupled formulation. Nine different simulation sequences were carried out by single-pass TIG welding of an octagonal pipe-plate joint, and the distributions of longitudinal and transverse residual stresses both on the outer and inner surfaces of the pipe were analyzed. The results suggest that the final residual stresses in the weld and its vicinity are not affected by the initial residual stresses of the structure. Selecting a suitable welding sequence can reduce the final residual stress in an octagonal pipe-plate joint.