On the stability of Jeffcott rotor in fluid-film bearings

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Authors

  • Milenko Stegić University of Zagreb, Croatia
  • Nikola Vranković University of Zagreb, Croatia
  • Nenad Kranjčević University of Zagreb, Croatia

Abstract

For some combinations of rotor speed and radial load, the pressure field of bearing fluid can perturb the pure rotational motion and disturb the normal operation of a rotating machine. Classical approach to the stability analysis of Jeffcott rotor in fluid-film bearings is modelling bearings as spring-damper elements and disregarding the external rotor damping [1, 5]. Nonlinear models are used to verify results obtained from a linearized model. This paper deals with the influence of external rotor damping on the size of stability regions. Stability analysis of the Jeffcott rotor in fluid-film bearings is performed by using both the linear model based on the linearization of bearing force around the static equilibrium position and the nonlinear model of the velocity linearization [2, 3].

References

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[3] S.H. Crandall. Velocity linearisation of the dynamic response of fluid-film bearings. In: L. Pust, ed., Proceedings of European Nonlinear Oscillation Conference, 119- 124. Institute of Thermomechanics, Prague, 1996.
[4] G. Genta. Vibration of Structures and Machines. Springer, New York. .. Tokyo, 1999.
[5] E. Krämer. Dynamics of Rotors and Foundations. Springer-Verlag, Berlin .. . Budapest, 1993.