Rotating machinery fault diagnosis using time-frequency methods

Time-frequency analysis has been found to be effective in monitoring the transient or time-varying characteristics of machinery vibration signals, and therefore its use in machine condition monitoring is increasing. This paper proposes the application of time-frequency methods, which can provide more information about a signal in time and in frequency and gives a better representation of the signal than the conventional methods in machinery diagnosis. In this paper, we review the machine diagnosis techniques based on the verification of classical vibration parameters. Then the necessity of using time-frequency analysis in machinery diagnostics is discussed. Finally, the theory of the Short-Time Fourier Transform, the Wigner-Ville distribution and the Wavelet transforms are briefly studied and their advantages are shown by some practical examples.