Crack detection for a Jeffcott rotor with a transverse crack: An experimental investigation

In this paper, an experimental investigation is carried out to verify the theoretical results of the dynamic behavior and the EMD based crack detection method for the cracked rotor proposed in our former research. The breathing crack in the rotor is simulated by a real fatigue crack. The whirl orbits during passage through the 1/2, 1/3 and 1/4 subcritical speeds are investigated. The dynamic responses in these subcritical speed zones are decomposed into several subcomponents by the EMD method, and the variation of the high-frequency component are studied. As a comparison, the fast Fourier transform method is used to derive the amplitude variation of the high order frequencies from the frequency spectra of the experimental vibration signal. The experimental results are well concordant with the theoretical analysis, which indicates that the EMD based crack detection method is practicable.