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Stability evaluation of three-layered journal bearing with slip/partial slip

T.V.V.L.N. Rao (Department of Mechanical-Mechatronics Engineering, The LNM Institute of Information Technology, Jaipur, India)
A.M.A. Rani (Department of Mechanical Engineering, University Technology Petronas, Bandar Seri Iskandar, Malaysia)
M. Awang (Department of Mechanical Engineering, University Technology Petronas, Bandar Seri Iskandar, Malaysia)
F.M. Hashim (Department of Mechanical Engineering, University Technology Petronas, Bandar Seri Iskandar, Malaysia)

Industrial Lubrication and Tribology

ISSN: 0036-8792

Article publication date: 8 May 2017

Abstract

Purpose

This paper aims to present stability of a three-layered journal bearing considering magnitude of the layers’ thicknesses and viscosities with slip/partial slip on the bearing surface.

Design/methodology/approach

Modified Reynolds equation based on one-dimensional analysis is derived for a three-layered journal bearing with slip/partial slip. Dynamic coefficients are derived based on infinitesimal perturbation method. Linearized stability analysis is presented taking into account slip/partial slip on bearing surface; thicknesses and viscosities of bearing surface layer; and core layer and journal surface layer.

Findings

Results of threshold speed and critical whirl frequency ratio coefficients (Cω, CΩ), stiffness (Kij for i = x,y) and damping (Bij for i = x, y) coefficients and threshold speed (ωs) and critical whirl frequency ratio (Ωs) are presented. The bearing surface is analyzed for slip (total surface with slip) and partial slip (partial surface with slip). The slip-on bearing surface reduces stability, while partial slip improves bearing stability. The threshold speed coefficient (Cω) decreases with slip on bearing surface. The threshold speed (ωs) and critical whirl frequency ratio (Ωs) are influenced by the variation of threshold speed coefficient (Cω) and critical whirl frequency ratio coefficient (CΩ), respectively. A three-layered journal bearing with partial slip and thick high viscosity bearing surface layer results in higher threshold speed coefficient and has a potential to improve stability of journal bearing. The analyses indicate that optimal angular extent of partial slip region (θs) enhances the stability of journal bearing.

Originality/value

The paper presents parametric study of stability coefficients (Cω and CΩ) and evaluation of threshold speed (ωs) and critical whirl frequency ratio (Ωs) of a three-layered journal bearing with slip/partial slip.

Keywords

Acknowledgements

This research is funded by Ministry of Education (MOE) Malaysia under FRGS-0153AB-K49 grant. The authors appreciate the support of The LNM Institute of Information Technology and Universiti Teknologi PETRONAS.

Citation

Rao, T.V.V.L.N., Rani, A.M.A., Awang, M. and Hashim, F.M. (2017), "Stability evaluation of three-layered journal bearing with slip/partial slip", Industrial Lubrication and Tribology, Vol. 69 No. 3, pp. 334-341. https://doi.org/10.1108/ILT-08-2016-0184

Publisher

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Emerald Publishing Limited

Copyright © 2017, Emerald Publishing Limited