Discussion on fatigue life estimation under multiaxial random loading: Comparison between time- and frequency-domain approach

In the present paper, two critical plane-based criteria proposed by Carpinteri et al. are discussed. Both criteria aim to estimate the fatigue life of smooth metallic structural components under multiaxial random loading, but one is formulated in time-domain whereas the other one in frequency-domain. Such criteria are here modified in order to improve their accuracy in terms of fatigue life estimation, and then applied to experimental fatigue data related to 18G2A structural steel tests available in the literature, performed on smooth specimens under random non-proportional bending and torsion loading.