Stress amplification effect and fatigue strength evaluation of marine thin plate welded structure considering welding deformation: Theoretical and experimental analysis

Abstract

Due to the low bending stiffness of thin plate welded joints, welding deformations such as welding dislocation, welding angle deformation and initial welding deformation are easy to occur in the welding process. The existence of these deformations will cause additional stress concentration effect and reduce the fatigue performance of thin-plate welded structures. Therefore, the influence of various welding deformations should be considered when evaluating the fatigue strength of the welded joints of thin plates. Combined with the test data, the calculation formula of stress amplification factor considering various welding deformations proposed by this paper is compared with the calculation formula in the existing literature and finite element calculation results. Moreover, the analytical formula is applied to the fatigue assessment of 5059 aluminum alloy welded joints. According to the evaluation results, it is found that the structural stress method and equivalent structural stress method based on the proposed bending stress amplification coefficient formula have good evaluation results for aluminum alloy thin plate specimens with welding deformations. Fatigue strength class curves suitable for thin plate aluminum alloy welded joints corresponding to different fatigue evaluation methods are further suggested.