A Parametric Analysis on Hull Penetration Position and Frame Spacing Leading to Minimal Welding Distortion

摘要

Hull penetration and openings are governed by standards, which ensure the structural integrity of the assembly. However, a number of stiffeners are usually welded to the panel, giving rise to welding residual stresses and distortion. This study identifies the optimal position and shape of penetration relative to various stiffener spacing configurations, leading to the least welding distortion. A numerical parametric study is adopted where an uncoupled thermo-elastoplastic technique based on the inherent strain method is used. The results have shown that the final distortion is highly dependent on the buckling mode shape predicted by the numerical models that in turn is influenced by the structural stiffness and support position of the assembly. When the models follow a similar buckling mode, the results have shown that smaller stiffener spacing leads to less distortion. Centrally positioning penetrations results in symmetric panel stiffness leading to near symmetric out-of-plane distortion and ultimately minimal distortion, when compared to positioning penetrations next to the stiffener. The difference in the predicted distortion for square and circular penetrations is relatively small when placed in the middle of the assembly. Nonetheless, when penetrations are placed close to the stiffener, circular penetrations are preferred to reduce distortion. Small circular penetrations gave rise to less overall distortions but more penetration residual twisting and rotations, particularly when placed close to the stiffener.