MEAN STRESS EFFECTS IN MULTIAXIAL FATIGUE

A multiaxial fatigue strain energy density parameter has been formulat ed which normalizes fatigue data obtained under a variety of mean stre ss levels and loading combinations. This parameter represents that pro portion of the overall strain energy contributed by the stresses and s trains on the critical or fracture plane. It is shown that multiaxiaI fatigue life data may be accurately correlated by applying this parame ter to the experimental results of Inconel 718 alloy subjected to a va riety of mean normal and shear stress levels, as well as to SAE 1045 s teel tested under tension, torsion and simultaneous tension and torsio n.