Prediction of welding deformation in stiffened structure by introducing thermo-mechanical interface element

•A thermo-mechanical interface element was developed to predict welding distortion.•The interface element model could enhance the calculation precision.•The validity of the new model was verified by large scale stiffened structures.

A thermo-mechanical interface element was developed to describe the effective penetration, the fillet weld size and the contact relationship between the skin plate and the stiffener during welding distortion simulation. Based on the interface element formulation, welding distortion in stiffened structures was predicted by means of thermal elastic–plastic finite element analysis. Comparisons between the traditional model and the interface element model were conducted. The results indicate that the calculated data of the interface element model are in better agreement with the experimental measurements. The influences of the welding sequence were discussed numerically based on these two models. The interface element model is more suitable for describing the effect of the welding sequence, which are of great importance on accurately predicting distortion in large scale structure welding. Simulations and experiments upon large scale structures were also carried out to verify the effectiveness of the developed numerical analysis procedure.