Fatigue Life Estimation of Thin-Walled Fillet-Welded Joints Under Constant Amplitude Loading

This study evaluates the fatigue life estimation performance of nominal, hot-spot, and notch stress-based approaches for thin-walled fillet-welded joints made of steel subjected to constant-amplitude loading. The employed dataset comprised ten configurations with nearly identical wall thicknesses and load asymmetry ratios, which differed mainly in their geometry and loading conditions. Assessing this dataset as a whole revealed that all three approaches exhibited a comparable average level of conservatism. However, the nominal and notch stress-based approaches exhibited pronounced scatter, leading to substantial configuration-to-configuration variations in the level of conservatism. The most consistent predictions, reflected by the lowest scatter, were observed for the hot-spot stress-based approach. Its performance could be further enhanced by extending the wall-thickness ranges over which the thickness corrections are derived from the actual wall thickness. The notch stress-based S-N data exhibited a clear tendency to separate into two approximately parallel curves corresponding to hollow section-based and plate-based configurations.