Time-frequency Analysis Method of Feature Extraction of Rotor Crack AE Signal

Acoustic emission(AE) signal of rotor crack is a non-stationary and non-linear signal.For non-stationary and non-linear signals,time-frequency analysis methods are feasible.Wavelet packet has the capability of decompsition and reconstruction and Pseudo Wigner-Vill time-frequency distribution has the better characteristics to time-variant signal,so we combine the two methods for the diagnosis of early crack fault.It is shown by experimental verification that this method can accurately extract crack fault feature from weak AE signal and the early crack fault can be effectively diagnosed.