An Experimental Investigation of Condition Monitoring for Notched Rotors Through Transient Signals and Wavelet Transform

Experimental studies considering the dynamic transient signals of a notched rotor (i.e. a rotor with a transverse open crack) are investigated in order to examine the possibility of detecting the presence of open cracks in rotating machinery for low or high rotor accelerations. Firstly, the orbital patterns, spectrum cascade plots of the Power Spectral Density, evolutions of the 2× amplitudes of rotor with and without an open transverse crack are compared and discussed in the case of low accelerations of the rotor system. Secondly, the non-stationary vibration signals of the rotor with an open transverse crack at high accelerations are investigated. The timefrequency features and a tool based on the Continuous Wavelet Transform (CWT) to detect open cracks in a rotor system are discussed. It is demonstrated that both the Continuous Wavelet Transform (CWT) and changes on the 2× harmonic components are robust indicators for crack detection.