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Chaos in the unbalance response of journal bearings


Brown, RD and Addison, P and Chan, AHC, Chaos in the unbalance response of journal bearings, Nonlinear Dynamics, 5, (4) pp. 421-432. ISSN 0924-090X (1994) [Refereed Article]

Copyright Statement

Copyright 1994 Kluwer Academic Publishers

DOI: doi:10.1007/BF00052452


The behaviour of non-linear systems often yield unexpected phenomena which are extremely sensitive to initial conditions. The hydrodynamic journal bearing is a common machine element which is strongly nonlinear for large excursions within the clearance space. A simple model of a rigid journal, supported hydrodynamically using a short bearing theory is shown to behave chaotically when the rotating unbalance force exceeds the gravitational load. At these values of the force ratio the time history of the response is very sensitive to initial conditions and a spectral analysis demonstrates a significant broadening from the expected peak at the rotational frequency. A once per revolution sampling of the time history (Poincaré plot) revealed an apparent aperiodic pattern. An estimate of the fractal dimension using the Grasberger-Procaccia algorithm resulted in a lower bound of 2.15, a typical result for low dimensional systems with significant dissipative action. The required levels of unbalance are only an order of magnitude greater than acceptable levels for rotating machinery and thus could be achieved with in-service erosion or minor damage. The subsequent non-synchronous response could result in fatigue and potential shaft failure.

Item Details

Item Type:Refereed Article
Keywords:chaos, unbalance, journal bearings
Research Division:Engineering
Research Group:Control engineering, mechatronics and robotics
Research Field:Automation engineering
Objective Division:Construction
Objective Group:Construction design
Objective Field:Civil construction design
UTAS Author:Chan, AHC (Professor Andrew Chan)
ID Code:111770
Year Published:1994
Web of Science® Times Cited:65
Deposited By:Office of the School of Engineering
Deposited On:2016-10-05
Last Modified:2016-11-07

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