ABSTRACT
For large structures in actual engineering practice such as shipbuilding, it is hard to realize the welding process simulation by thermal elastic plastic FEM owing to the calculation time and cost. Elastic FEM based on inherent strain theory was developed to investigate welding distortion of large scale and complex welded structures. Structural responses induced by welding were treated as initial strains in the local structure near weld lines. Deng & Murakawa (2007, 2008) used the elastic FEM to predict welding distortion of a large structures considering both local shrinkage and root gap and the accuracy were verified by experimental results. Based on the calculation results of small joints by thermal elastic plastic FEM, elastic FEM
1 INTRODUCTION
As an efficient and reliable joining method, welding technology is widely used in shipbuilding, with high productivity and flexibility during manufacture process of structural components fabrication, sections assembly and blocks closure (Zacke 2011). However, it is inevitable that residual distortion and stress exists in the welded structures due to the non-uniform expansion and shrinkage of material near weld line. Welding distortion not only affects the appearance of products but also degrades the structural performance due to the loss of structural integrity and dimensional accuracy. It is meaningful to predict welding induced distortion at the design stage itself, for the purpose of controlling such distortion in production (Tsai et al. 1999).
