Title: Vibration signature analysis of high speed unbalanced rotating shaft supported on ball bearings

Authors: S.H. Upadhyay, S.P. Harsha, S.C. Jain

Addresses: S.V. Patel Institute of Technology, Vasad – 388306, Anand, India. ' Indian Institute of Technology, Roorkee – 247667, Uttaranchal, India. ' Indian Institute of Technology, Roorkee – 247667, Uttaranchal, India

Abstract: In this paper, non-linear dynamics of a high speed unbalanced rotor supported on ball bearings is analysed. The approach presented here accounts for contacts between balls and inner/outer races. The non-linearity in the rotor bearing system has been considered mainly due to Hertzian contact, unbalanced shaft and radial internal clearance. In the formulation, the contacts between balls and inner/outer races are considered as non-linear springs and also used non-linear damping, which is developed by correlating the contact damping force with the equivalent contact stiffness and contact deformation rate. The results show the appearance of instability and chaos in the dynamic response as the speed of unbalanced shaft is varied. The appearance of the regions like periodic, sub-harmonic and chaotic behaviour is observed to be strongly sensitive to the speed of the rotating shaft. Techniques like Poincare maps and frequency spectra are used to elucidate and to illustrate the diversity of the system behaviour.

Keywords: vibration signature analysis; high speed rotating shafts; unbalanced rotating shafts; ball bearings; frequency spectra; nonlinear vibration; chaos; Poincare maps; mechanical design; design engineering; nonlinear dynamics; rotor bearings; contact damping; contact stiffness; contact deformation; vibration damping.

DOI: 10.1504/IJDE.2009.028651

International Journal of Design Engineering, 2009 Vol.2 No.2, pp.191 - 204

Published online: 21 Sep 2009 *

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