Statistical correlation of 3D scanned weld geometry distributions and fatigue life for different welding methods

Abstract The relationship between local weld geometry and fatigue life has been extensively studied over the past decades, driven by the need to enhance structural integrity and optimize costs throughout a structure’s service life. While numerous studies have explored the influence of weld geometry on fatigue strength, the comparative effect of different welding methods under comparable weld geometry quality remains largely unexplored. Furthermore, the influence of local geometric variations for each welding method has not been systematically evaluated. This study explores a large dataset of laser-scanned butt welds, analyzing key geometric parameters. The dataset is categorized by welding method (laser-hybrid welding, submerged arc welding, and flux core arc welding), and statistical distributions are examined to assess variations in weld geometry and compliance with ISO 5817 quality groups. The characteristic fatigue life for each quality group is estimated. The correlation between geometric factor and fatigue life is evaluated through the residual analysis of stress-life curve linear fitting. According to the findings, different geometry features dominate depending on the welding method. The fracture location is strongly influenced by angular misalignment, while fatigue strength is better explained by quantile-based analysis of local geometry. These results provide a basis for future predictive modeling and quality assessment in welded structures.