Vibration characteristics of a rotating flywheel-flexible coupling system with misalignment fault: Experiment and simulation

To avoid harmful and even catastrophic influences on internal combustion engine-generator set, it is essential to investigate early faults such as misalignment, rotor rubbing, shaft cracks, and bearing faults. To study the effect of the misalignment of the elastic coupling on vibration characteristics of the rotor system, experiment with different misalignment amplitudes and types is carried out on a flywheel-elastic coupling rotor test rig. Vibration responses of the rotor system with different amplitudes of parallel and angular misalignment are illustrated by amplitude frequency response curves, orbit plots and frequency spectra. Super-harmonic resonance phenomenon is revealed. Based on the misalignment of the high elastic coupling, dynamical equations of a generator rotor system, excited also by unbalanced magnetic pull and mass unbalance, are derived using the energy method and numerically investigated by the Runge-Kutta method. The theoretical results are in good accordance with the experimental ones. Besides, a new phenomenon of the flywheel-elastic coupling vibration system is found in the experiment.