A second-order third-moment method for calculating the reliability of fatigue

Probabilistic assessments are a useful supplement to deterministic analyses and can also be used as an aid to decision making in areas such as safety analyses, design studies and deployment of resources on maintenance, inspection and repair. Because the initial crack size, the stress, the material properties and other factors that may affect the fatigue crack growth are statistically distributed, the first-order second-moment method is often adopted to calculate the reliability of fatigue of industrial structures. In this paper, a second-order third-moment method is presented and a three-parameter Weibull distribution is adopted to reflect the influences of skewness of the probability density function. The proposed method that has more characteristics of those random variables that are concerned in reliability analysis is obviously more accurate than the traditional first-order second-moment method with a case study.