Variance of the fatigue damage in non-Gaussian stochastic processes with narrow-band power spectrum

This paper presents two theoretical models to assess the variance of the fatigue damage in stationary narrow-band and non-Gaussian stochastic processes. The models extend two solutions existing in the literature and restricted to Gaussian processes. The new models here developed exploit a non-linear transformation that links Gaussian and non-Gaussian domains based on skewness and kurtosis coefficients, which are used to quantify the deviation from the Gaussian distribution. Monte Carlo numerical simulations in time-domain are performed to confirm the correctness of the proposed non-Gaussian models, and to investigate the sensitivity of the variance of the damage to the skewness, kurtosis, and inverse slope of the stress versus life (S-N) curve. An example is finally presented to demonstrate the increase of the failure probability due to non-Gaussian effects in the stochastic loading.