Time and frequency domain models for multiaxial fatigue life estimation under random loading

Engineering structures and components are often subjected to random fatigue loading produced,for example, by wind turbulences, marine waves and vibrations. The methods available in the literature forfatigue assessment under random loading are formulated in time domain or, alternatively, in frequency domain.The former methods require the knowledge of the loading time history, and a large number of experimentaltests/numerical simulations is needed to obtain statistically reliable results. The latter methods are generallymore advantageous with respect to the time domain ones, allowing a rapid fatigue damage evaluation. In thepresent paper, a multiaxial criterion formulated in the frequency-domain is presented to estimate the fatiguelives of smooth metallic structures subjected to combined bending and torsion random loading. A comparisonin terms of fatigue life prediction by employing a time domain methods, previously proposed by the authors, isalso performed.