NUMERICAL SIMULATION OF WELDING DISTORTION USING EQUIVALENT THERMAL STRAIN SCHEME

Welding distortion is one major problem aroused in component assembly, which is typical in marine engineering. Predicting the deformations accurately and reducing the values effectively are very important to maintain good assembly quality and provide useful advice for welding technology. A thermal strain method, based on the inherent strain theory, is developed to precisely predict welding distortion. The paper describes an equivalent thermal strain formulation that derives the height of the layer with orthotropic expansion property and the coefficients of expansion. Welding deformations such as angular distortion and transverse shrinkage can be easily obtained by elastic FEM for welded part. In this study, inherent deformations are calculated with the results of thermal elastic-plastic finite element method, and two typical welding joints are simulated by the new developed method. The deformation results of the proposed method show good agreement with experimental results. Furthermore, welding distortion of a large structure is also simulated by the proposed elastic FEM. Comparison between numerical results and experiment results verifies the effectiveness of the proposed method in simulating large welding parts.