The Influence of Mechanical Constraint on the Welding Deformation of a Large-scale Ship Bottom Grillage

摘要

Based on thermal elasto-plastic finite element method (FEM), the welding simulation of a large-scale ship bottom grillage was carried out in this paper. The structure comprises five transverse floors and three longitudinal girders. In order to enhance modeling and calculation efficiency, shell elements with section integration are adopted to model the entire structure and solid elements to model the local details of weld line region. Linear constraint equations are established between degrees of freedom of shell and solid elements. The techniques of segmented moving heat source model and static substructure are adopted in order to reduce the computation time of models. Some key welding parameters such as heat input, welding speed and welding sequence are considered in the analysis. The welding deformations under two different constraints, including global bending, transverse angular distortion and torsion distortion, are analyzed and compared in this paper.