Abstract:

：Fatigue life determines the length of the service life of engineering structure under normal working conditions, and it is very important to predict the fatigue life accurately for the fatigue design of parts. Due to mechanical parts subjecting to random variable load during the working time, the interaction effect between loads is significant which changes the fatigue damage caused by single cycle load. Ignoring this effect will affect the accuracy of the estimation of fatigue life. In the current study, the fatigue damage accumulation rule cannot be considered. To solve this problem, a method for estimating the fatigue life of components by combining the non-homogeneous Poisson stochastic process function with the theory of the concomitant damage is put forward, which takes the problem of loading sequence caused by the interaction effect between loads into account. The accuracy of this method is verified by the random loading test. It is applied to the estimation of the fatigue life of wind turbine blades. The results show that this method is reliable and effective, which provides a new path for the fatigue reliability design of wind turbine blades.

Key words: accompanying damage, fatigue life, Poisson stochastic process, sequence of loading, random variable amplitude load