Fatigue strength of welded joints of marine aluminum alloy extrusion stiffened plate considering welding effects

Abstract

Due to the low stiffness of thin-plate welded structure, the influence of welding effect on fatigue evaluation of thin-plate welded structure cannot be ignored. Extruded stiffened plates are tried to be used in hull structures because of their excellent forming technology, which can greatly reduce welding deformation and defects. By carrying out fatigue tests of extruded reinforced welded joints and traditional T-shaped welded joints, the S-N curves of typical T-welded joints are obtained and compared. Furthermore, the residual stress and welding deformation of stiffened model and traditional T-model are predicted by numerical simulation. The welding effects are introduced into the calculation of hot spot stress as the initial value, and the hot spot stress class curves of extruded reinforced welded joints and traditional T-welded joints are renewed. Compared with traditional welded joints, extruded welded joints are less affected by residual stress and welding deformation. The study revealed that residual stress and welding deformation exhibited a higher sensitivity to the fatigue strength of traditional thin-plate welded structures.