Continuum based methods are traditionally thought to be of little value in describing boundary lubrication, or the mode of lubrication in molecular scale films that may occur at asperity interactions during the sliding of nominally flat surfaces. There is considerable experimental evidence, which suggests that the classical theory may be valid with modification to films as thin as several nanometers. In addition, lubricants, which exhibit viscous liquid properties in bulk, may form attached solid-like elastic layers when confined between solid surfaces. In the present paper, the simple “elastic foundation” concept is used to model the elastic layers, in contact with a viscous fluid film. Several typical bearing contact flow problems are solved, giving hope that boundary lubrication may eventually be modeled in the same manner as hydrodynamic lubrication in thicker films.

Issue Section:
Technical Papers
Keywords:
rheology, lubrication, viscoelasticity, confined flow
Topics:
Boundary lubrication, Fluids, Journal bearings, Lubricants, Lubrication, Pressure, Rheology, Stress, Wedges, Film thickness, Bearings, Flow (Dynamics), Friction, Fluid films, Viscoelasticity
1.
Israelachvili, J., 1992, Intermolecular & Surface Forces, Academic Press, London.
2.
Gee
,
M. L.
,
McGuiggan
,
P. M.
, and
Israelachvili
,
J.
,
1990
, “
Liquid to Solid-Like Transitions of Molecularly Thin Films Under Shear
,”
J. Chem. Phys.
,
93
, No.
3
, pp.
1895
–
1906
.
3.
Homola
,
A.
,
Israelachvili
,
J.
,
Gee
,
M.
, and
McGuiggan
,
P.
,
1989
, “
Measurements of and Relation Between the Adhesion and Friction of Two Surfaces Separated by Molecularly Thin Liquid Films
,”
ASME J. Tribol.
,
111
, pp.
675
–
682
.
4.
Tonck
,
A.
,
Georges
,
J. M.
, and
Loubet
,
J. L.
,
1988
, “
Measurements of Intermolecular Forces and the Rheology of Duodecane Between Alumina Surfaces
,”
J. Colloid Interface Sci.
,
126
, No.
1
, pp.
150
–
163
.
5.
Georges
,
J. M.
,
Millot
,
S.
,
Loubet
,
J. L.
, and
Tonck
,
A.
,
1993
, “
Drainage of Thin Films Between Relatively Smooth Surfaces
,”
J. Chem. Phys.
,
98
, pp.
7345
–
7360
.
6.
Yoshizawa
,
H.
, and
Israelachvili
,
J.
,
1993
, “
Fundamental Mechanisms of Interfacial Friction
,”
J. Phys. Chem.
,
97
, No.
43
, pp.
300
–
11
.
7.
Chan
,
D. Y. C.
, and
Horn
,
R. G.
,
1985
, “
The Drainage of Thin Liquid Films Between Solid Surfaces
,”
J. Chem. Phys.
,
83
, No.
10
, pp.
5311
–
5324
.
8.
Hamrock, B. J., Fundamentals of Fluid Film Lubrication, McGraw-Hill, New York, pp. 141–165.
9.
Thompson
,
P. A.
, and
Robbins
,
M. O.
,
1990
, “
Shear Flow Near Solids: Epitaxial Order and Flow Boundary Conditions
,”
Phys. Rev. A
,
41
, No.
12
, pp.
6830
–
6837
.
10.
Thompson, P. A., Robbins, M. O., and Grest, G. S., 1993, “Simulations of Lubricant Behavior at the Interface With Bearing Solids,” Thin Films in Tribology, D. Dowson et al., eds., Elsevier, New York, pp. 347–360.
11.
Hu, Y. Z., Wang, H., and Guo, Y., 1993, “Molecular Dynamics Simulation of Poiseuille Flow in Ultra Thin Films,” Proceedings of the International Symposium on Tribology, Beijing, China, pp. 58–65.
12.
Landman
,
U.
,
Luedtke
,
W. D.
,
Burnham
,
N. A.
, and
Colton
,
R. J.
,
1990
, “
Atomistic Mechanisms and Dynamics of Adhesion, Nanoindentation, and Fracture
,”
Science
,
248
, pp.
454
–
461
.
13.
Tichy
,
J. A.
,
1995
, “
A Surface Layer Model for Thin Film Lubrication
,”
STLE Tribol. Trans.
,
38
, No.
1
, pp.
108
–
118
.
14.
Tichy
,
J. A.
,
1995
, “
A Porous Media Model for Thin Film Lubrication
,”
ASME J. Tribol.
,
117
, No.
1
, pp.
16
–
21
.
15.
Auslander, F., and Sideroff, F., 1996, “Nanorheological Behavior of Confined Liquid Layers for Normal Contact,” The Third Body Concept, D. Dowson et al., eds., Elsevier, New York, pp. 195–203.
16.
Johnson, K. L., 1985, Contact Mechanics, Cambridge University Press, New York, pp. 104–107.
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