Numerical simulation of welding distortion in large structures

Welding is a crucial manufacturing process and widely used in industries to assemble various products including ships, automobiles, trains and bridges. Welding distortion often results in problems such as dimensional inaccuracies during the assembly and increased fabrication costs. Therefore, prediction and reduction of welding distortion are critical to improve the quality of welded structures. Welding distortion during the assembly process is affected by not only local shrinkage due to rapid heating and cooling, but also root gap and misalignment between parts to be welded. In this study, based on inherent strain theory, an elastic finite element method is developed to precisely predict welding distortion during the assembly process considering both local shrinkage and root gap. First, thermal elastic-plastic finite element method is employed to estimate inherent deformations for different typical welding joints. Second, the proposed elastic FEM is used to predict welding distortion for large welded structures based on the obtained inherent deformations. Meanwhile, the influence of initial gap on welding distortion is investigated. Finally, experiments are carried out to verify the simulated results. The effectiveness of the proposed elastic FEM is confirmed using experimental results. (c) 2007 Elsevier B.V. All rights reserved.