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Rheological Characteristics for Thin Film Elastohydrodynamic Lubrication

Published online by Cambridge University Press:  05 May 2011

H.-M. Chu*
Affiliation:
Department of Mechanical Engineering, Yung-Ta Institute of Technology & Commerce, Ping-Tung, Taiwan 909, R.O.C.
R. T. Lee*
Affiliation:
Department of Mechanical and Electro-Mechanical Engineering, National Sun Yat-Sen University, Kaohsiung, Taiwan 804, R.O.C.
S. Y. Hu*
Affiliation:
Department of Marine Engineering, National Kaohsiung Marine University, Kaohsiung, Taiwan 811, R.O.C.
Y.-P. Chang*
Affiliation:
Department of Mechanical Engineering, Kun Shan University of Technology, Tainan, Taiwan 710, R.O.C.
*
*Assistant Professor
**Professor
***Associate Professor
*Assistant Professor
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Abstract

This paper uses three lubrication models to explore the differential phenomenon in the status of thin film lubrication (TFL). According to the viscous adsorption theory, the modified Reynolds equation for thin film elastohydrodynamic lubrication (TFEHL) is derived. In this theory, the film thickness between lubricated surfaces is simplified as three fixed layers across the film, and the viscosity and density of the lubricant vary with pressure in each layer. Under certain conditions, such as a rough or concentrated contact of a nominally flat surface, films may be of nanometer scale. The thin film elastohydrodynamic lubrication (EHL) analysis is performed on a surface forces (SF) model which includes van der waals and solvation forces. The results show that the proposed TFEHL model can reasonably calculate the film thickness and the average relative viscosity under thin film EHL. The adsorption layer thickness and the viscosity influence significantly the lubrication characteristics of the contact conjunction. The differences in pressure distribution and film shape between surface forces model and classical EHL model were obvious, especially in the Hertzian contact area. The solvation force has the greatest influence on pressure distribution.

Type
Articles
Copyright
Copyright © The Society of Theoretical and Applied Mechanics, R.O.C. 2005

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References

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