Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 32468
Detection of Coupling Misalignment in a Rotor System Using Wavelet Transforms

Authors: Prabhakar Sathujoda


Vibration analysis of a misaligned rotor coupling bearing system has been carried out while decelerating through its critical speed. The finite element method (FEM) is used to model the rotor system and simulate flexural vibrations. A flexible coupling with a frictionless joint is considered in the present work. The continuous wavelet transform is used to extract the misalignment features from the simulated time response. Subcritical speeds at one-half, one-third, and one-fourth the critical speed have appeared in the wavelet transformed vibration response of a misaligned rotor coupling bearing system. These features are also verified through a parametric study.

Keywords: Continuous wavelet transform, flexible coupling, rotor system, sub critical speed.

Digital Object Identifier (DOI):

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 641


[1] Piotrowski, J. Shaft Alignment Handbook, third ed., CRC Press, Ohio, 2006.
[2] Sinha JK, Lees AW and Friswell MI. Estimating unbalance and misalignment of a flexible rotating machine from a single run-down. J Sound Vib 2004; 272: 967–989.
[3] Fei, C., Fengrui, B., Chao, C., Song, W., and Heng, Z. Research on double span rotor system driven by motorized spindle with coupling misalignment, Advances in Mechanical Engineering (2019) 11(4), 1–17.
[4] Rivin, E. I. Design and application criteria for connecting couplings. Trans. ASME, J. Mechanisms, Transm. Automn Des., 1986, 108, 96-104.
[5] Woodcock, J. S. The effect of couplings upon the vibrations of the rotating machinery. In Proceedings of International Conference on Flexible Couplings, University of Sussex, Brighton, 1977, pp. E-1-1 - E-1-20 (Michael Neale and Associates Limited).
[6] Gibbons, C. B. Coupling misalignment forces. In Proceedings of 5th Turbomachinery Symposium, Gas Turbine Laboratories, Texas A&M University, Texas, 1976, 111-116.
[7] Sekhar, A. S. and Prabhu, B. S. Effects of coupling misalignment on vibrations of rotating machinery. J. Sound Vibr., 1995, 185(4), 655-671.
[8] Xu, M. and Marangoni, R. D. Vibration analysis of a motor flexible coupling rotor system subjected to misalignment and unbalance, Part I: theoretical model and analysis. J. Sound Vibr., 1994, 176(5), 663-679.
[9] Al-Hussain KM. Dynamic stability of two rigid rotors connected by a flexible coupling with angular misalignment. J Sound Vib 2003; 266: 217–234.
[10] Patel, T.H. and Darpe, A.K. Experimental investigations on vibration response of misaligned rotors, Mech. Syst. Sig. Process. 2009, 23, 2236–2252.
[11] Qu, L., Lin, J., Liao, Y., & Zhao, M. Changes in rotor response characteristics based diagnostic method and its application to identification of misalignment. Measurement 2019, 138, 91-105.
[12] Prabhakar, S., Sekhar, A.S., and Mohanty, A.R. Vibration analysis of a misaligned rotor-coupling-bearing system passing through the critical speed. J Mech Eng Sci 2001, 215, 1417–1428.
[13] M.C.S. Reddy, M.C.S. and Sekhar, A.S. Detection and monitoring of coupling misalignment in rotors using torque measurements, Measurement 2015, 61, 111–122.
[14] 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. (2019):
[15] Nelson,,H. D. and McVaugh, J. M. The dynamics of rotor bearing systems using finite elements. Trans. ASME, J. Engng for Industry, 1976, 98(2), 593-600.
[16] Kramer, E. Dynamics of Rotors and Foundations, pp. 224 - 226 (Springer-Verlag, Berlin).