An analysis of the classic friction modeling in lubricated contacts is conducted. Its major deficiency for soft materials (low-elastic moduli) leading to significant overstating of friction in heavily loaded isothermal and thermal lubricated contacts is revealed. An improved model of friction in a heavily loaded lubricated contact is proposed. The model is based on incorporating the tangential displacements of the solid surfaces in contact, leading to a significant reduction of the frictional stress due to the decrease of the actual sliding of lubricated surfaces. Generally, this frictional stress reduction increases with the slide-to-roll ratio, and it is extremely important for high slide-to-roll ratios for which classic approaches lead to unrealistically overestimated values of frictional stresses. The high slide-to-roll ratio values can be found in many practical applications, such as clutches. Several examples of the frictional stress calculated based on this model as well as the comparison with the classical results are given for the case of smooth solid surfaces and lubricants with Newtonian rheology. Also, the results allow to take a look at the role and the necessity of considering thermal and lubricant non-Newtonian effects on solution of various EHL problems for such heavily loaded contacts.

References

References
1.
Johnson
,
K. L.
,
1985
,
Contact Mechanics
,
1st ed.
,
Cambridge University Press
,
Cambridge, UK
.
2.
Jacod
,
B.
,
2002
, “
Friction in Elasto-Hydrodynamic Lubrication
,” Ph.D. thesis, University of Twente, Enschede, The Netherlands.
3.
Jacod
,
B.
,
Venner
,
C. H.
, and
Lugt
,
P. M.
,
2004
, “
Influence of Longitudinal Roughness on Friction in EHL Contacts
,”
ASME J. Tribol.
,
126
(
3
), pp.
473
481
.
4.
Jacod
,
B.
,
Venner
,
C. H.
, and
Lugt
,
P. M.
,
2001
, “
A Generalized Traction Curve for EHL Contacts
,”
ASME J. Tribol.
,
123
(
2
), pp.
248
253
.
5.
Jacod
,
B.
,
Venner
,
C. H.
, and
Lugt
,
P. M.
,
2003
, “
Extension of the Friction Mastercurve to Limiting Shear Stress Models
,”
ASME J. Tribol.
,
125
(
4
), pp.
739
746
.
6.
Bair
,
S.
, and
Winer
,
W. O.
,
1982
, “
Some Observations in High Pressure Rheology Off Lubricants
,”
ASME J. Lubr. Technol.
,
104
(
3
), pp.
357
364
.
7.
Bair
,
S.
, and
Winer
,
W. O.
,
2000
, “
The Pressure-Viscosity Coefficient at Hertzian Pressure and Its Relation to Concentrated Contact Traction
,”
26th Leeds-Lyon Symposium on Tribology
, pp.
433
443
.
8.
Bair
,
S.
,
2000
, “
Pressure-Viscosity Behavior of Lubricants to 1.4 GPa and Its Relation to EHD Traction
,”
STLE Tribol. Trans.
,
43
(
1
), pp.
91
99
.
9.
Evans
,
C. R.
, and
Johnson
,
K. L.
,
1980
, “
The Rheological Properties of EHD Lubricants
,”
Proc. Inst. Mech. Eng., Part C
,
200
(5), pp.
303
312
.
10.
Evans
,
C. R.
, and
Johnson
,
K. L.
,
1980
, “
Regimes of Traction in Elastohydrodynamic Lubrication
,”
Proc. Inst. Mech. Eng., Part C
,
200
(5), pp.
313
324
.
11.
Hoglund
,
E.
, and
Jacobson
,
B.
,
1986
, “
Experimental Investigation of the Shear Strength of Lubricants Subjected to High Pressure and Temperature
,”
ASME J. Tribol.
,
108
(4), pp.
571
578
.
12.
Johnson
,
K. L.
, and
Tevaarwerk
,
J. L.
,
1977
, “
Shear Behavior of Elastohydrodynamic Oil Films
,”
Proc. R. Soc. London, Ser. A
,
356
(
12
), pp.
215
236
.
13.
Moore
,
A. J.
,
1981
, “
The Derivation of Basic Liquid Flow Properties From Disk Machine Traction Tests
,”
7th Leeds-Lyon Symposium on Tribology
, pp.
280
295
.
14.
Yasutomi
,
S.
,
Bair
,
S.
, and
Winer
,
W. O.
,
1984
, “
An Application of Free Volume Model to Lubricant Rheology
,”
ASME J. Tribol.
,
106
(2), pp.
291
303
.
15.
Kudish
,
I. I.
, and
Covitch
,
M. J.
,
2010
,
Modeling and Analytical Methods in Tribology
,
Chapman & Hall/CRC Press
.
16.
Kudish
,
I. I.
,
2013
,
Elastohydrodynamic Lubrication for Line and Point Contacts: Asymptotic and Numerical Approaches
,”
Chapman & Hall/CRC Press
,
Taylor & Francis Group
.
17.
Kudish
,
I. I.
,
2000
, “
Formulation and Analysis of EHL Problems for Soft Materials
,”
ASME J. Tribol.
,
122
(
3
), pp.
705
710
.
18.
Galin
,
L. A.
,
1980
,
Contact Problems in Elasticity and Visco-Elasticity
,
Nauka Publishing
,
Moscow, Russia
.
19.
Van-Dyke
,
M.
,
1964
,
Perturbation Methods in Fluid Mechanics
,
Academic Press
,
New York
.
You do not currently have access to this content.