Identifier

etd-10302006-082326

Degree

Doctor of Philosophy (PhD)

Department

Mechanical Engineering

Document Type

Dissertation

Abstract

The dissertation focuses on the frictional characteristics of journal bearings as represented by the Stribeck curve. The behavior of lift-off speed and the factors that affect it are explored. An equation is proposed for predicting the lift-off speed. The comparison between the experimental results of oil- and grease-lubricated journal bearings with a mixed elastohydrodynamic lubrication model for line contacts is indicative of good agreement in the mixed lubrication regime. Efforts are made to modify the surface profile of bushing by putting dimples on its surface. Experimental results show that with proper dimensions of dimples, the friction performance of journal bearings can be improved, particularly for light oils. The friction hysteresis of oil and grease-lubricated journal bearings undergoing oscillatory motion are investigated under different load, with or without oil, oil type, oil inlet temperature, oscillating frequency, and bushing material. A dynamic friction model for infinitely long journal bearing is also developed that demonstrates the existence of hysteresis loop. Finally, a thermal analysis of oscillatory journal bearings is carried out by finite element method using ANSYS. Simulations are found to be in good agreement with experimental measurement of temperature at four locations along the circumference.

Date

2006

Document Availability at the Time of Submission

Secure the entire work for patent and/or proprietary purposes for a period of one year. Student has submitted appropriate documentation which states: During this period the copyright owner also agrees not to exercise her/his ownership rights, including public use in works, without prior authorization from LSU. At the end of the one year period, either we or LSU may request an automatic extension for one additional year. At the end of the one year secure period (or its extension, if such is requested), the work will be released for access worldwide.

Committee Chair

Michael M. Khonsari

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