Numerical simulation of residual stresses in aluminum alloy welded joints

The lightweight design makes thin-plate welded structures used widely, especially for the aluminum alloy thin-plate welded structure, it is very important to study the fatigue fracture properties of the structure considering the influence of residual stress. A solid model of a butt joint of aluminum alloy with a double-pass weld is established. Both the welding temperature fields and residual stress fields are simulated through the thermal elastic-plastic method. The welding experiment is also performed with the corresponding joint, which is welded by means of metal inert-gas (MIG) welding. Consequently, the computational and experimental results of residual stress are in good agreement. Moreover, the thermal elastic-plastic method is employed to calculate the residual stress fields of typical welded joints. Based on the inherent strain theory, the transverse and longitudinal inherent strain of the joints are decomposed from the total strains and applied to both solid and shell models of the three types of joints to calculate the residual stress fields of them. The results of the solid and shell models using the two methods are practically consistent, which indicates that the inherent strain method can predict the residual stress on the shell model efficiently and accurately. Thus, the method of predicting the welding residual stress of thin-plate structures based on the inherent strain is proposed, which provides a reference for the structural fatigue assessment under the influence of residual stress.