Mean stress effect on fatigue life estimation for Inconel 718 alloy

Uniaxial and biaxial fatigue tests related to Inconel 718 specimens are simulated using the critical plane-based multiaxial fatigue criterion by Carpinteri et al. in conjunction with a like Smith-Watson-Topper (SWT) relationship. More precisely, specimens subjected to proportional and non-proportional loading consisting of tension, torsion, and combined tension and torsion loading under strain control are analysed, being characterised by both zero and non-zero mean values. Fatigue life is computed through the novel formulation here proposed and compared with the experimental fatigue life in terms of number of loading cycles needed to form a surface crack whose length is equal to 1 mm