Font Size: 

In the present paper, a new computationally-efficient frequency domainformulation of the critical plane-based Carpinteri-Spagnoli (C-S) criterion is proposedto evaluate the fatigue lives of smooth metallic structures subjected to multiaxial randomloading. The critical plane orientation is here proposed to depend on the PowerSpectral Density (PSD) matrix of the stress tensor. Then, the PSD function of anequivalent normal stress is defined by considering a linear combination of the PSDfunctions of the normal stress and the projected shear stress along the direction ofmaximum variance, with such stresses acting on the critical plane. The equivalent PSDfunction obtained allows us to apply the Tovo-Benasciutti method in order to determinethe fatigue life of the structure being examined. The frequency domain formulation ofthe C-S criterion is applied to some relevant random fatigue tests related to smoothspecimens under non-proportional bending and torsion random loading.