0
Research Papers: Mixed and Boundary Lubrication

On the Behavior of Friction in Lubricated Point Contact With Provision for Surface Roughness

[+] Author and Article Information
H. Sojoudi

Department of Mechanical Engineering, Louisiana State University, 2508 Patrick Taylor Hall, Baton Rouge, LA 70803

M. M. Khonsari1

Department of Mechanical Engineering, Louisiana State University, 2508 Patrick Taylor Hall, Baton Rouge, LA 70803khonsari@me.lsu.edu

1

Corresponding author.

J. Tribol 132(1), 012102 (Nov 12, 2009) (8 pages) doi:10.1115/1.4000306 History: Received July 09, 2009; Revised September 23, 2009; Published November 12, 2009; Online November 12, 2009

This paper presents a simple approach to predict the behavior of friction coefficient in the sliding lubricated point contact. Based on the load-sharing concept, the total applied load is supported by the combination of hydrodynamic film and asperity contact. The asperity contact load is determined in terms of maximum Hertzian pressure in the point contact while the fluid hydrodynamic pressure is calculated through adapting the available numerical solutions of elastohydrodynamic lubrication (EHL) film thickness formula for smooth surfaces. The simulations presented cover the entire lubrication regime including full-film EHL, mixed-lubrication, and boundary-lubrication. The results of friction, when plotted as a function of the sum velocity, result in the familiar Stribeck-type curve. The simulations are verified by comparing the results with published experimental data. A parametric study is conducted to investigate the influence of operating condition on the behavior of friction coefficient. A series of simulations is performed under various operating conditions to explore the behavior of lift-off speed. An equation is proposed to predict the lift-off speed in sliding lubricated point contact, which takes into account the surface roughness.

FIGURES IN THIS ARTICLE
<>
Copyright © 2010 by American Society of Mechanical Engineers
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Figure 5

Total friction coefficient as a function of velocity (lubricant viscosity effect), FT=20 N

Grahic Jump Location
Figure 6

Total friction coefficient as a function of velocity (roughness effect), η0=1×10−2 Pa s and FT=40 N

Grahic Jump Location
Figure 7

(a) Hydrodynamic scaling factor γ1 for different roughnesses, η0=1×10−2 Pa s and FT=40 N. (b) Asperity scaling factor γ2 for different roughnesses, η0=1×10−2 Pa s and FT=40 N.

Grahic Jump Location
Figure 8

Total friction coefficient as a function of velocity (roughness effect), σs=0.04 μm and FT=40 N

Grahic Jump Location
Figure 4

Load effect on the friction coefficient, η0=8×10−3 Pa s. (a) Asperity contact friction coefficient and (b) hydrodynamic friction coefficient.

Grahic Jump Location
Figure 3

Total friction coefficient as a function of velocity (load effect), η0=8×10−3 Pa s

Grahic Jump Location
Figure 2

The film thickness parameter and effect of pressure-viscosity relations on the total friction coefficient, FT=40 N and η0=0.01 Pa s

Grahic Jump Location
Figure 1

Variation of the total friction coefficient (present simulations and experimental results (9))

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In