Stress intensity factors for elliptical surface cracks in round bars with different stress concentration coefficient

In this study the fatigue properties of laser beam welded thin sheet aluminium are examined. Modelling the hydrogen pores as three-dimensional globular defects shows that their effect on fatigue strength exceeds the effect of the moderate weld toe curvature at butt welds. The cyclic strength of overlap joints with a slot weld is characterised by a two-dimensional crack-like notch between the sheets. Different modes of loading can be reduced to a single curve with a notch stress approach and a fictitious notch radius of 0.05 mm. The approaches allow fatigue test data derived from specimen geometry to be transferred to real structures with a master curve concept.