Vibrations Analysis of a Rotor Supported by Tilting-Pad Journal Bearings with Considering of Geometric Nonlinearity

Document Type : Research Article

Authors

1 Kharazmi University

2 Department of Mechanical Engineering, Kharazmi University

3 Department of Mechanical Engineering, Faculty of Engineering, Kharazmi University, P.O. Box 15719-14911, Tehran, Iran

Abstract

Vibrations of a continuous rotor with uniform circular cross section supported by two tilting-pad journal bearings at both ends are analyzed. Since the shaft is slender, shear deformation is neglected, but, gyroscopic effect is considered (Rayleigh beam theory). In addition, geometric nonlinearity due to large deformation of the rotor is considered. Based on short bearing assumption, an analytical model of a tilting-pad journal bearing with laminar and turbulence flows has been derived. Galerkin method is applied to discretize differential equations of motion. By solving discrete rotorbearing system equations, the response is obtained. For further investigation, responses of rotor-bearing system in different situations are presented. Comparing the responses of the linear and nonlinear rotor with two tilting-pad journal bearings at both ends shows that the nonlinear rotor has less amplitude than linear rotor and nonlinear rotor is closer to reality. In addition, nonlinear model has a larger natural frequency in comparison to the linear rotor. Using turbulence flow makes the bearing stiffer and have less amplitude than laminar flow. Reducing viscosity of lubricant leads to increase of amplitude of response and shows that higher viscosity make the bearing stiffer.

Keywords

Main Subjects

References

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Amirkabir Journal of Mechanical Engineering
Volume 52, Issue 1
April 2020
Pages 141-154

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