Vibration analysis of rotors for the identification of shaft misalignment Part 2: experimental validation

In Part 1 of this paper, a theoretical model to determine the dynamic behaviour of misaligned shaft rotors connected by a flexible coupling was developed. In this Part 2, experimental tests are performed to validate the model and simulation results obtained in Part 1. Vibratory characteristics, such as the frequency spectrum, waveform and phase shifts of the spectral components across the coupling are presented for different magnitudes of misalignment and types of coupling. Traditional vibration analysis rules used in practical predictive maintenance to diagnose shaft misalignment are evaluated. The influence of the frequency response functions on the amplitude of the spectral components and on the phase shifts of the spectral components across a coupling were studied. Finally, some practical conclusions for more reliable shaft misalignment identification using vibration analysis are suggested.