Study On Welding Stress Field Of Aluminum Alloy Based On Numerical Simulation

Welding structures are widely used in ships, vehicles, marine engineering, aerospace and other fields due to a lot of advantages. In the welding process, parts of an area are heated up to high temperature and then rapidly cooled, largely welding residual stresses appear in the weldment inevitably, the residual stresses in welding structures can directly influence their ability of bearing loads, strength and precision. Therefore, it is of great practical significant to predict welding residual stresses and optimize the welding process. If the welding process can be simulated by computer, we will easily determine the technological process and reduce the cost.This paper focused on a three-dimensional numerical simulation of pipe-plate joint welding by6061-T6aluminum in welding temperature field and stress field by the finite element software ABAQUS. And the regular pattern of the temperature field and stress field in several mutual coupling welds was obtained. Considering the penetration of the welding arc, the ellipsiod heat source was chosen and used FORTRAN language to compile program to apply moving heat source load in the welding simulation.In order to improve the accuracy of the numerical simulation, special concern was given to the nonlinear relationship between temperature and the material properties. In the actual welding process, welding temperature field and stress field are bi-directional couple, so this paper considered the bi-directional couple effects between the two physical fields. The real distribution of the residual stresses was acquired by an X-ray diffraction technique, good agreement was found between numerical and experimental data within weld zone.Nine different simulation sequences were carried out to investigate the effect of welding sequence on welding residual stress distribution, The results suggested that backstep welding can cut down the final residual stress. Secondly, the welding parameters such as welding current, welding voltage and welding speed were discussed, the change of the parameters had no effect on the regularities of the residual stress distribution but influence the peak value of the residual stresses.