Frequency domain analysis method of nonstationary random vibration based on evolutionary spectral representation

Abstract

Purpose A novel frequency domain approach, which combines the pseudo excitation method modified by the authors and multi-domain Fourier transform (PEM-FT), is proposed for analyzing nonstationary random vibration in this paper. Design/methodology/approach For a structure subjected to a nonstationary random excitation, the closed-form solution of evolutionary power spectral density of the response is derived in frequency domain. Findings The deterministic process and random process in an evolutionary spectrum are separated effectively using this method during the analysis of nonstationary random vibration of a linear damped system, only modulation function of the system needs to be estimated, which brings about a large saving in computational time. Originality/value The method is general and highly flexible as it can deal with various damping types and nonstationary random excitations with different modulation functions.