Research on welding deformation of hollow thin-walled complex structural parts based on plane bending theory of constant section beam

In order to effectively forecast the welding deformation and deformation pattern of hollow thin-walled aluminum alloy complicated structural parts, based on the plane deformation theory of constant section beam and workpiece constraint conditions, the complex feature structure was split and the deflection curve equation of each position was constructed. Moreover, the inherent strain method was used to solve the welding equivalent load, and the welding deformation was calculated by combining the equivalent load with the deflection curve equation. On the basis of the theoretical load value, the welding deformation at different positions during and after welding was numerically simulated by finite element simulation. What's more, the theoretical deformation of each plate is verified by the simulated deformation results. Besides, the simulation deformation results of post welding deformation are verified by welding experiment. The results show that the shrinkage deformation of the welding position is the largest, the transverse and longitudinal deformation are 0.007 mm and 0.018 mm respectively, the error rates of theory and simulation are 5.2 % and 5.5 % respectively. What's more, the welding deformation at the non-welding position is mainly reflected in the vertical direction of the upper skin plate. After the external constraints are released, the actual maximal deformation values of the two sides of the upper skin plate are 0.08 mm and 0.064 mm respectively. The deformation presents an M-shaped distribution, which is comparable to the deformation distributions of theory and simulation. The deformation value caused by the welding process accounts for 10 % of the total deformation after the removal of external constraints. In addition, the welding process is the main stage of forming the deformation distributions at each position, and the release of external constraints is the main factor leading to the final deformation.