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Effects of Couple Stresses on Pure Squeeze EHL Motion of Circular Contacts

Published online by Cambridge University Press:  05 May 2011

H.-M. Chu ,
W.-L. Li  and
S. Y. Hu
H.-M. Chu*
Affiliation:
Department of Mechanical Engineering, Yung-Ta Institute of Technology & Commerce, Ping-Tung, Taiwan 909, R.O.C.
W.-L. Li*
Affiliation:
Department of Mechanical Engineering, National Kaohsiung University of Applied Sciences, Kaohsiung, Taiwan 807, R.O.C.
S. Y. Hu*
Affiliation:
Department of Marine Engineering, National Kaohsiung Marine University, Kaohsiung, Taiwan 811, R.O.C.
*
*Assistant Professor
**Professor
***Associate Professor
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Abstract

A method for investigating the pure squeeze action in an isothermal elastohydrodynamically lubrication (EHL) problem, i.e., circular contacts lubricated with couple stress fluid, was developed. A constant load condition was used in the calculations. The initial conditions such as pressure profiles, normal squeeze velocities, and film shapes were obtained from the classical hydrodynamic lubrication theory at a specified large central film thickness. The coupled transient modified Reynolds, elasticity deformation, and load equilibrium equations are solved simultaneously. The simulation results reveal that the effect of the couple stress is equivalent to enhancing the lubricant viscosity, thus enlarging the film thickness. The effect of couple stress in thin film lubrication varies with film size. That is, the thinner the lubricating film is, the more obvious the effect of couple stress is. For larger characteristic length, materials parameter, and load, the central pressure, central film thickness, and rigid separation are larger than those of smaller characteristic length under the same load. The time needed to achieve maximum central pressure and the Hertzian pressure increases with increasing characteristic length.

Keywords

EHLSqueeze filmCouple stress fluidsMicrocontinuum theory.
Type
Technical Note
Information
Journal of Mechanics , Volume 22 , Issue 1 , March 2006 , pp. 77 - 84
Copyright
Copyright © The Society of Theoretical and Applied Mechanics, R.O.C. 2006

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