Application of a criterion for lifetime prediction under multiaxial random loading

A multiaxial high-cycle fatigue criterion for random loading, recently proposed by the authors [1], is here applied to some tests characterized by variable amplitude combined bending and torsion. The criterion, applicable to hard metals, considers an equivalent uniaxial stress defined through a nonlinear combination of stress components acting on the critical plane, whose orientation is correlated to a weighted mean position of the principal stress directions. A specific cycle counting method and a general damage model are then employed to process such an equivalent stress and to predict lifetime.