PSI - Issue 79

Santi Marchetta et al. / Procedia Structural Integrity 79 (2026) 224–232

232

In contrast, for titanium joints, the lack of IIW reference FAT curves and the absence of a SED scatter band specifically calibrated for welded configurations limit the applicability of both methods. A preliminary strategy based on normalizing the steel FAT curves with respect to the Young’s modulus was implemented, to perform the comparison in terms of strain rather than stress. While this approach appears to be safe and conservative for fatigue design purposes, it remains an approximate solution that requires further validation. Moreover, the SED results for titanium joints fell outside the scatter band proposed by Meneghetti et al. , which was originally derived for the base material. These findings confirm that a new SED scatter band specifically tailored to welded Ti-6Al-4V is needed. Overall, the study highlights that while the hotspot stress and SED methods are reliable for steel welded joints, their transferability to titanium alloys is not straightforward. 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