Abstract: The
nonlinear properties of rotating machinery vibration signals are
presented. The relationship between faults and quadratic phase
coupling is discussed. The mechanism that gives rise to
quadratic phase coupling is analyzed, and the coupling models
are summarized. As a result, higher order spectra analysis is
introduced into fault diagnosis of rotors. A brief review of the
properties of higher order spectra is presented. Furthermore,
the bicoherence spectrum is employed to extract the features
that signify the machinery condition. Experiments show that
bicoherence spectrum patterns of different faults are quite
different, so it is proposed to identify the faults in rotors.
Key words: Rotor
Fault diagnosis Quadratic phase coupling Higher order spectra Bicoherence spectrum
Manuscript
received on January 17, 2000; revised manuscript July 10, 2000
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