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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Fig. 4. Fatigue test results of BW_TYPE, BW_UND, filtered database and design S-N curves

Specimen TYPE_4 did not fail after 5×10⁶ cycles; consequently, the test was stopped, and the specimen was excluded from the statistical evaluation. As only five specimens were considered for BW_TYPE series, the resulting fatigue strength may be slightly conservative compared to the six specimens in the BW_UND series. prEN 1993 ‑ 1 ‑ 9 (CEN 2023b) defines a design category DC 71 for the butt weld connections welded from one side, considering the failure occurs on the weld root side. However, in the current experimental investigation, all failures occurred at the weld toe. The fatigue strength calculated for the BW_TYPE series was equal to 74 MPa. This relatively high value was achieved despite the presence of imperfections such as undercuts (quality level D), lack of fusion (quality level D), and porosity (quality levels C and

Fig. 5. Specimen BW_UND_3 (a) presence of undercut (b) failure location