Fatigue Reliability Assessment Using FORM

Abstract

#An efficient method for time-dependent fatigue reliability analysis is proposed in this paper based on a random process representation of material fatigue properties and a nonlinear damage accumulation rule. The proposed method uses the first-order reliability method (FORM) to calculate the reliability index based on a time-dependent limit state function. The proposed methods include the covariance structure of the stochastic damage accumulation process under variable amplitude loading. The proposed method is verified with direct Monte Carlo method first. Then, a wide range of fatigue data available in the literature is used to validate the proposed methodology, covering several different types of metallic and composite materials under different variable amplitude loading. It is observed that the correlation effect of the input random variables has a large effect on the fatigue reliability assessment. The significance of the correlation effect depends on different materials.