A Design Oriented Reliability Methodology for Fatigue Life Under Stochastic Loadings

Abstract

Fatigue damage analysis is critical for systems under stochastic loadings. To estimate the fatigue reliability at the design level, a hybrid reliability analysis method is proposed in this work. The First Order Reliability Method (FORM), the inverse FORM, and the peak distribution analysis are integrated for the fatigue reliability analysis at the early design stage. Equations for the mean value, the zero upcrossing rate, and the extreme stress distributions are derived for problems where stationary stochastic processes are involved. Then the fatigue damage is analyzed with the peak counting method. The developed methodology is demonstrated by a simple mathematical example and is then applied to the fatigue reliability analysis of a shaft under stochastic loadings. The results indicate the effectiveness of the proposed method in predicting fatigue damage and reliability.