Approach for the probabilistic fatigue assessment of welded joints based on the local geometry of the weld seam

Welded joints show large variation of the weld toe geometry along the weld seam, which is one important reason for the comparably large scatter in fatigue life. Therefore, it is crucial to take the local geometry at the weld toe into account, to reduce the conservatism in fatigue assessment of welded joints. This study is based on the IBESS procedure for the calculation of the fatigue strength, whereby the evaluation of local geometrical parameters is carried out by means of 3D surface scans. The approach is validated against 26 fatigue test series. The fatigue life is in general overpredicted, whereas good agreement is achieved for high stress ratio ( R=0.5 R=0.5 ). A sensitivity analysis conducted with IBESS shows that weld toe radii rho < 2 mm and flank angle alpha < 30(degrees) have a significant influence on the calculated fatigue strength. In contrast to this, no strong correlation between rho and the fatigue strength was determined experimentally in this study.