PSI - Issue 28

C. Mallor et al. / Procedia Structural Integrity 28 (2020) 619–626 C. Mallor et. al. / Structural Integrity Procedia 00 (2020) 00 – 00

624

(a)

(b)

(c) (d) Fig. 4. History values of the moments of provided by the Monte Carlo (MC) and by the probabilistic NASGRO equations (Pr.Eq.): (a) Expected value of and the deterministic (Det.) number of cycles; (b) Standard deviation of ; (c) Skewness of ; (d) Kurtosis of . The results demonstrated that:  The expected value, the standard deviation or variance, the skewness and the kurtosis provided by the MC and by the probabilistic NASGRO equations are really close, showing a good consistency to consider the FSOA to be reasonably accurate.  The key advantage of the FSOA method is the lower computational time, similar to a deterministic calculation.  Due to the accuracy and the computational efficiency, the FSOA outperforms the conventional MC method. At this point, the first to fourth moments of the lifespan probability distribution are available after applying the full second-order approach. Therefore, it is time to construct the probability density functions (PDF) from the prescribed moments. The moments of fatigue life for a crack depth equal to 50 mm are gathered in Table 1.