Simulating welding residual stress and deformation in a multi-pass butt-welded joint considering balance between computing time and prediction accuracy

Abstract

In this study, three different modeling approaches, namely, a model with moving heat source, a model with high effective heat source named instantaneous heat source, and a model with instantaneous heat source as well as coarser mesh density, were employed to systematically investigate welding residual stress and deformation in a multi-pass butt-welded joint. Moreover, the difference of material properties especially yield stress between base metal and weld has been considered. In addition, the hole-drilling method and three-coordinate measuring technique were employed to obtain welding residual stress distribution and deformation, respectively. The comparison between simulation results and measurements suggests that the model with moving heat source can obtain a good prediction of both welding residual stress and deformation, while the model with instantaneous heat source can only provide a reasonable result for welding residual stress but fail to predict welding deformation. However, the latter model can save a large amount of computing time. Numerical results indicate that the mesh density in the longitudinal direction has an insignificant influence on the calculated results of welding residual stress and deformation if the developed instantaneous heat source model has been used. From the viewpoint of engineering application, the model with instantaneous heat source model and coarser mesh density is potentially able to predict welding residual stress distribution in thick-plate joint using a shorter computing time.