Prediction of Laser Welding Distortion in Cylindrical Shell Structures Using Direct Application of Inherent Strain

Abstract

In this study, a simplified analysis method by directly applying inherent strain (DIS) at integration points to predict welding distortion of cylindrical shell structures was suggested. The 3D thermo-elastoplastic method demands substantial computational time. The strain as direct boundary (SDB) simplified method using virtual temperature encounters challenges in consecutive thermal structural analysis including welding distortion. The suggested method (that is, DIS) offers the advantage of enabling continuous thermal structural analysis after welding distortion analysis, with computational efficiency. To calculate inherent strain, lap laser welding with 2 mm and 2.6 mm SUS304 plates was performed, measuring fusion and heat-affected zone sizes via cross-sectional observations. Using the calculated inherent strain and our suggested direct input method, we conducted welding analysis and welding test on cylindrical shell structures. Comparison of welding distortion under same conditions revealed radial distortion difference within approximately 10%, corresponding with the experimental result and confirming a computational time reduction by over 2,000 times than those of thermo-elastoplastic analysis. Therefore, an efficient and accurate prediction of welding distortion was achievable through the suggested method.