A Study of Joint Time-Frequency Analysis-Based Modal Analysis

Traditional modal-analysis methods use either time-domain or frequency-domain approaches. Because vibration signals are generally nonstationary, time and frequency information is needed simultaneously in many cases. This paper presents an overview of the applications of joint time-frequency methods for modal analysis. Since a joint time-frequency analysis can decouple vibration modes, it has an advantage, especially when information about the excitation is not available. In this paper, wavelet and Gabor analyses for the modal parameter identification are compared. Two reconstruction approaches - the FFT method and the Gabor expansion method$are also compared. Numerical simulations and experiments have been carried out