Fatigue crack propagation analysis for welded joint subjected to bending

In this paper, fatigue tests have been conducted on specimens, which are flat plate with a notch, stud-welded plate, T-shaped fillet welded joint and cruciform fillet welded joint, in such a way that fatigue cracks could be initiated and propagated in bending load. Under bending load, surface crack has formed flat semi-ellipse and propagated to about 80% of plate thickness before failure. Besides, the fatigue crack propagation life of cracked welded joint specimen has been predicted using fracture mechanics method. In particular, a correction factor equation has been developed for covering linearly varying stress distribution along crack propagation path under bending load. This equation has been applied to calculating stress intensity factor (SIF) in relation to fatigue life prediction.