Effect of boundary conditions on residual stress and distortion in T-joint welds

• Welding imperfections of T-joint are investigated under the various boundary conditions.
• Transverse residual stress is increased significantly under high restraint condition.
• High restraint condition results in a decrease of vertical deformation.
• The angular distortion is decreased significantly under the high restraint condition.

This study investigates the welding residual stress and distortion in T-joint welds under various mechanical boundary conditions. An experimentally calibrated and sequentially coupled thermal and mechanical 3D finite element (FE) model is developed, and Goldak's double ellipsoidal heat source model is implemented into the numerical model. The results show that the transverse residual stress, vertical displacement, angular distortion and transverse shrinkage depend significantly on the mechanical boundary conditions, and the influence on the longitudinal residual stress is not significant. Applying the clamped condition along the edges during the welding process and releasing it after the T-joint cools down to ambient temperature can significantly reduce the welding-induced geometric imperfections.