HOS Analysis of Measured Vibration Data on Rotating Machines with Different Simulated Faults

Vibration-based condition monitoring (VCM) has gained tremendous successes in the detection and differentiation of faults associated with rotating machines, through the installation of various numbers of vibration transducers at individual bearing pedestals of the monitored machine. This chapter however exposes the future potentials of the use of the higher order spectra (HOS) i.e., the bispectrum and the trispectrum for rotating machines faults diagnosis (FD). The aim of this is to achieve a significant reduction in the number of vibration transducers required at each bearing pedestal, without necessarily compromising valuable information required for the diagnosis. Four cases (healthy, shaft misalignment, cracked shaft and shaft rub) were simulated on an experimental rig with two rigidly coupled shafts supported by four ball bearings. Only four accelerometers (one at each bearing pedestal) were used for this study. The HOS results were compared for the different conditions of the rig. The observations and findings are presented in the chapter.