Abstract: The dynamic distortions with restraints are investigated by using 3D multi-body coupling numerical simulation. A multi-body coupling finite element model including clamp, clamping strip, worktable and welding piece is developed to perform the numerical simulation. In the model, spring elements with specified stiffness are adopted to simulate the elastic clamps, displacement constraints are imposed on the spring elements to implement the clamping of the welding piece before welding, and the contact conditions among welding piece, clamping strip and worktable are used to reflect the dynamic constraint imposed on the welding piece. The results of numerical simulation and experiment show that the clamping force is dynamic during welding, the variety of the clamping force is similar to that of welding distortion in z direction, and the clamping force before welding affects the distortion of welding piece after welding. The simulation results of multi-body coupling finite element model agree well with the experimental ones.

Key words: Multi-body coupling, 3D finite element, Dynamic restraints, Welding distortion