An empirical mode decomposition-based frequency-domain approach for the fatigue analysis of nonstationary processes

摘要

Mechanical structures in service are often subjected to irregular loads, which are typically idealized as stationary random processes. However, the service loads in real applications are often nonstationary ones, in which case conventional frequency-domain methods are no longer applicable. Here, a novel frequency-domain approach based on empirical mode decomposition is developed for the fatigue analysis of nonstationary processes. A simplified approach is introduced to calculate the rainflow cycle distributions of non-Gaussian intrinsic mode functions. Two typical nonstationary processes in engineering practice are simulated numerically to validate the proposed method. The proposed method is applied to fatigue life estimation of a dynamical structure under nonstationary excitations. Reliable life estimations are obtained within much less computation time than the time-domain method. The results verify the applicability and effectiveness of the proposed method for the fatigue analysis of nonstationary processes.