Numerical and experimental investigations of outside corner joints welding deformation of an aluminum autonomous catamaran vehicle by inherent strain/deformation FE analysis

The welding deformation considerably plays a vital role in the production accuracy and efficiency of marine structures. In this study, welding deformation due to three outside corner joints (with angles of 60, 70 and 140°) used in an aluminum catamaran hull is evaluated by considering the length and welding speed parameters. The deformation is predicted via two numerical procedures based on finite element computations. Thermal-Elastic-Plastic (TEP) analysis is applied on local 3D solid models for each of the three outside corner joints to calculate inherent strain for global shell model of an aluminum catamaran to obtain deformation elastically based on inherent deformation theory. Validations of numerical results were performed by using metallographic observations and welding distortion. For more accuracy the softening effect was investigated by Vickers Microhardness test. The results from both TEP and FE elastic analyses indicate reasonably good agreement with experimental results. Besides, in the global shell model of the catamaran, out-of-plane welding deformation will occur significantly near the maximum angle of outside corner joint (140-degree) where the maximum welding distortion is obtained. Along with the welding speed parameter has considerable influence on decreasing distortion which results in reducing time-consuming and cost in the catamaran production stage.