Vibration Analysis of a Rotating Flywheel/Flexible Coupling System with Angular Misalignment and Rubbing Using Smoothed Pseudo Wigner–Ville Distributions



Detection of early faults such as misalignment, rotor rubbing, shaft crack and bearing fault is necessary to avoid harmful and even catastrophic influences on rotating machinery.


In this paper, the accelerating horizontal and pitching vibration responses of flywheel/flexible coupling model of an actual diesel generator, with angular misalignment and rubbing faults, are investigated using the smoothed pseudo-Wigner–Ville distributions (SPWVDs).

Results and Conclusions

Numerical simulations are performed through the dynamical equations of the flywheel/flexible coupling system; the results suggest that when an angular misalignment fault occurs, the super-harmonic resonance of order 3 can be found in the horizontal and pitching vibration signals. Meanwhile, both the 3fr and 5fr components (i.e., 3 and 5 times of the rotating frequencies) can also be found in SPWV distribution spectra. When rubbing fault occurs, more abundant sub- and super-harmonic frequency components can be observed in SPWV distribution spectra. Overall, the investigation shows that the smoothed pseudo-Wigner–Ville distribution spectra reveal obvious differences between the acceleration responses of the rotating system with different faults.

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This work is supported by the Natural Science Foundation of China through the Grants (51575378) and Natural Science Foundation of Tianjin City (Grant number 19JCZDJC38800).

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Correspondence to Qian Ding.

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Liu, Z., Wu, K., Ma, Z. et al. Vibration Analysis of a Rotating Flywheel/Flexible Coupling System with Angular Misalignment and Rubbing Using Smoothed Pseudo Wigner–Ville Distributions. J. Vib. Eng. Technol. 8, 761–772 (2020).

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  • Flywheel/flexible coupling system
  • Angular misalignment detection
  • Rubbing detection
  • Smoothed pseudo-Wigner–Ville distribution