Finite element modeling of GMAW process; evolution and formation of residual stresses UPON cooling

Fusion arc welding processes often generate substantial residual stresses, which may alter the performance of welded structures. Residual stresses are the results of incompatible elastic and plastic deformations in a body. Destructive techniques are generally used to experimentally determine residual stresses. Employment of these methods would not often be possible or practical in industry. In this study, three-dimensional (3D) and two-dimensional (2D) finite element simulations and experimental work have been performed to analyze the thermomechanical problem of GMAW and to obtain a full-field view of the residual stress field. One of the purposes of this study is to examine the formation of residual stresses upon cooling of a weldment. Comparisons of the results of 2D and 3D finite element models reveal many three-dimensional features in the thermomechanical problem of GMAW. The magnitude of longitudinal residual stresses obtained from the 2D model, however, compares well with the results obtained from the 3D model.