Out-of-plane distortion prediction of large thin-walled structures induced by friction stir welding

A numerical method is developed to predict the out-of-plane distortion for large thin-walled structures induced by friction stir welding. Considering the constraint of non-welded region in a large structure, the non-uniform stress distribution along the weld is accurately computed with a small structure. The welds in the small and large structures are divided into the beginning, middle, and end regions due to the non-uniform stress situation. By using the interpolation function, the stress components in various regions of the small structure are mapped to the corresponding locations in the large thin-walled structure. Then, the out-of-plane distortion of the large structure is computed when the clamps are released. The predicted residual stress and distortion for the large welded structure are in accordance with the experimental data.