PSI - Issue 75

Kevin Mouradian et al. / Procedia Structural Integrity 75 (2025) 616–624 Kevin Mouradian et al. / Structural Integrity Procedia (2025)

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5. Conclusions This paper investigates the impact of undercut on the fatigue strength of butt weld connections. A total of 12 specimens were tested under cyclic loading. Non-destructive testing methods were applied to accurately detect and measure imperfections, allowing for their classification according to the quality levels defined in ISO 5817 (CEN 2023a). The experimental results were then compared with the database used to derive the S – N curves in prEN 1993‑1‑9 (CEN 2023b). The following conclusions were drawn: • Despite the BW_TYPE specimens exhibiting imperfections corresponding to various quality levels, their fatigue resistance remained within the scatter band of the “filtered database”. Therefore, it is questionable whether quality level B was consistently achieved by the tests included in the database. • Undercuts with heights ranging from 0.54 mm (QL D) to 1.48 mm (QL