Fatigue assessment of laser stake-welded T-joints

This paper aimed to investigate the geometrical variations of laser stake-welded T-joints and their influence on fatigue assessment. Another aim was to determine which of the rref = 1 mm, rref = 0.05 mm, and J-integral assessment approaches are applicable for this joint type. Because of the specimen geometry and the loading condition in this study, J-integral approach was equivalent to mode I notch stress intensity approach. Accurate measurements of geometry were taken. Statistical analysis of the weld geometry showed that all the geometrical properties are normally distributed. The results of the fatigue assessment showed that all the approaches applied have a relatively small scatterband and are valid for this joint type. The fatigue strength at 2 million cycles, estimated by all approaches, corresponded to the fatigue strength of other welded steel joints from the literature. However, in case of rref = 0.05 mm approach, fatigue strength at 2 million cycles proposed in literature, appeared to be slightly conservative for laser stake-welded T-joints. All the approaches, applied in this study, had the slope of the fatigue resistance curves different from the usual m = 3.