Analysis and Comparison of Frequency-domain Approaches of Fatigue Life Prediction

This paper provides a brief review of several frequency-domain approaches of fatigue life prediction, specifically the narrow-band approximation, Wirsching-Light, Tovo-Benasciutti and Dirlilk models. By using sample calculation, this paper adopts rain-flow cycle counting method within the time-domain to obtain the stress cycles as well as their mean value and amplitude, which can be used to evaluate the accumulated fatigue damage. Then based on the results of fatigue cumulative damage of time-domain calculation, this paper detects the applicability and accuracy of the four frequency-domain approaches under different irregular factors. The results show that when stochastic stress process gets close to narrow-band random process, W-L method can predict the fatigue cumulative damage results more accurately. And with the decrease of the irregular factors, stochastic stress process gets closer to wide-band random process, and thus T-B method and Dirlik method can estimate the fatigue cumulative damage results more accurately.