Welding sequence optimization using the strain direct boundary method based on the welding induced change in structural stiffness

The method proposed in this study is to determine the welding sequence to suppress welding de-formation using the strain directed as boundary (SDB) method. Welded joints are modeled by constructing tack welds and gaps as kinematic constraints in shell models. In addition, the SDB method considering the elastoplastic properties is used to evaluate the effect on the previous welding procedure. The results of the constructed analysis model are compared with the experimental results. The residual strain of each weld is calculated using the verified model, and joint stiffness is determined and compared by considering this together with the relationship between tensile stress and shrinkage strain of the weld. The optimal welding sequence is determined by comparing the stiffness of each welding joint, and this is compared and verified with the experimental results. In addition, it is confirmed that the determined welding sequence reduced the out-of-plane deformation by 2.01 % compared to the original welding sequence. The proposed method thus provides an analytical approach for welding sequence design.