ABSTRACT
This chapter investigates the welding residual stress and distortion in a deck grillage welds. Some heavy weights loadings are placed on the panels between two adjacent stiffeners of the grillage during welding process and removed after the structure cooling down to ambient temperature. Welding as an efficient means of connection is widely used throughout the construction process of ship hull. Thermal elasto-plastic Finite Element Method is an effective way to predict the welding deformation of ship structure. A combined heat source model is used in thermal analysis to simulate the heat input distribution of welding torch. In the practical fabrication, ship blocks are usually placed on a support platform or pin jig when they are welded. All girders and stiffeners are tack-welded to the plate initially to provide an overall rigidity of the structure before welding. Applying heavy weight loadings on panels is an effective way to reduce welding-induced imperfection.
