Fatigue strength assessment of misaligned laser beam welded T-joints by effective stress method

Abstract This paper investigates the effect of the joint misalignment and the weld geometry on the fatigue strength of successive double-sided laser beam welded AA2024 and AA7075 T-joints using AA4047 filler wire. A finite element model was set up considering the misalignment and the weld geometry to obtain the notch stress. The effective notch stress was calculated by the fictitious radius concept and a microstructural length of 0.15 mm was estimated. Master design curves are proposed for different weld toe radii and microstructural length. The experimental results were better characterized by both a reference weld toe radius of 0 mm and a microstructural length of 0.15 mm. Furthermore, the geometric imperfections caused by variations on the weld toe generate fractures initiated by crack multinucleation.