Fatigue Life of 2024-T3 Aluminum under Variable Amplitude Multiaxial Loadings: Experimental Results and Predictions

This paper investigates fatigue behavior under variable amplitude multiaxial service loadings using 2024-T3 aluminum alloy. Experimental results for smooth and notched specimen fatigue tests under axial, torsion, and combined axial-torsion loadings are compared to predictions based on von Mises equivalent stress-based approaches. Predictions using the SWT mean stress correction were in better agreement with experimental results than those based on Modified Goodman. The stress-based approaches predicted fatigue life reasonably well for notched specimens where a local uniaxial stress state always exists for the geometry considered, but not so well for smooth specimens where multiaxial loading effects come into play.