The physical conditions (pressure, shear stress, temperature) generated in an elastohydrodynamic (EHD) contact are the main parameters governing the evolution of the physico-chemical properties of the lubricant within the contact. This paper presents in-situ measurements of pressure in an EHD point contact using Raman microspectroscopy. Two model lubricants are studied: a pure polyphenyl ether (5P4E) oil and a mixture of this oil with a liquid crystal. The influence of load and speed on the pressure distributions is investigated. The Petrusevich pressure spike is measured and its evolution with the operating parameters is in good agreement with the theoretical predictions. The addition of the liquid crystal to the base oil leads to an important diminution of the mixture viscosity, and consequently of the film thickness in the contact. The different rheological properties of the lubricants induce significant variations of the pressure profiles.

1.
Dowson, D., and Higginson, G. R., 1966, Elastohydrodynamic Lubrication, The Fundamentals of Roller and Gear Lubrication, Pergamon Press, Oxford.
2.
Ranger
,
A. P.
,
Ettles
,
C. M. M.
, and
Cameron
,
A.
,
1973
, “
Solution of the Point Contact Elastohydrodynamic Problem
,”
Proc. R. Soc. London, Ser. A
,
346
, pp.
227
244
.
3.
Hamrock
,
B. J.
, and
Dowson
,
D.
,
1976
, “
Isothermal Elastohydrodynamic Lubrication of Point Contacts, Part I: Theoretical Formulation
,”
ASME J. Lubr. Technol.
,
98
, pp.
223
229
.
4.
Greenwood
,
J. A.
,
1972
, “
An Extension of the Grubin Theory of Elastohydrodynamic Lubrication
,”
J. Phys. D
,
5
, pp.
2195
2211
.
5.
Hamrock
,
B. J.
, and
Dowson
,
D.
,
1977
, “
Isothermal Elastohydrodynamic Lubrication of Point Contacts, Part III: Fully Flooded Contacts
,”
ASME J. Lubr. Technol.
,
99
, pp.
264
276
.
6.
Lubrecht, A. A., 1987, “Numerical Solution of the EHL Line and Point Contact Problem Using Multigrid Techniques,” Ph.D. thesis, (ISBN 90-9001583-3) University of Twente, Enschede, The Netherlands.
7.
Spikes
,
H. A.
,
1999
, “
Thin Films in Elastohydrodynamic Lubrication: the Contribution of Experiment
,”
Proc. Inst. Mech. Eng., Part J: J. Eng. Tribol.
,
213
, pp.
335
352
.
8.
Astridge
,
D. G.
, and
Longfield
,
M. D.
,
1967
, “
Capacitance Measurements of Oil Film Thickness in a Large-Radius Disc and Ring Machine
,”
Proc. Inst. Mech. Eng.
,
182
(3N), pp.
89
96
.
9.
Cameron
,
A.
, and
Gohar
,
R.
,
1966
, “
Theoretical and Experimental Studies of the Oil Film in Lubricated Point Contact
,”
Proc. R. Soc. London, Ser. A
,
291
, pp.
520
536
.
10.
Hamilton
,
G. M.
, and
Moore
,
S. L.
,
1971
, “
Deformation and Pressure in an Elastohydrodynamic Contact
,”
Proc. R. Soc. London, Ser. A
,
322
, pp.
313
330
.
11.
Bartz
,
W. J.
, and
Ehlert
,
J.
,
1976
, “
Influence of Pressure Viscosity of Lubricant Oils on Pressure, Temperature, and Film Thickness in Elastohydrodynamic Rolling Contacts
,”
ASME J. Lubr. Technol.
,
98
, pp.
501
508
.
12.
Safa
,
M. M. A.
,
Anderson
,
J. C.
, and
Leather
,
J. A.
,
1982
, “
Transducers for Pressure, Temperature and Oil Film Thickness Measurement in Bearings
,”
Sens. Actuators
,
3
, pp.
119
128
.
13.
Marginson
,
H. J.
,
Sayles
,
R. S.
, and
Olver
,
A. V.
,
1995
, “
Limitations of Thin Film Microtransducers in Highly Loaded Contacts
,”
Tribol. Int.
,
28
, No.
8
, pp.
517
521
.
14.
Cann
,
P. M.
, and
Spikes
,
H. A.
,
1991
, “
In Lubro Studies of Lubricants in Contacts using FTIR Absorption Spectroscopy
,”
Tribol. Trans.
,
34
, No.
2
, pp.
248
256
.
15.
Cann, P. M., Aderin, M., Johnston, G. J., and Spikes, H. A., 1992, “An Investigation into the Orientation of Lubricant Molecules in EHD Contacts,” Wear Particles, Proc. 18th Leeds-Lyon Symp. Trib., Lyon, D. Dowson et al., eds., Elsevier, New York.
16.
Mansot, J. L., 1986, “Study of Pressures in a Sphere/Plane Contact with a Thin Organic Layer at the Interface,” (in French) Ph.D. thesis, University of Lyon I, France, N.86-50.
17.
Gardiner
,
D. J.
,
Baird
,
E.
,
Gorvin
,
A. C.
,
Marshall
,
W. E.
, and
Dare-Edwards
,
M. P.
,
1983
, “
Raman Spectra of Lubricants in Elastohydrodynamic Entrapments
,”
Wear
,
91
, pp.
111
114
.
18.
Gardiner
,
D. J.
,
Baird
,
E.
,
Craggs
,
C.
,
Dare-Edwards
,
M. P.
, and
Bell
,
J. C.
,
1989
, “
Raman Microspectroscopy of a Working Elastohydrodynamic Contact
,”
Lubr. Sci.
,
1
, pp.
301
313
.
19.
Petrusevich, A. I., 1951, “Fundamental Conclusions from the Hydrodynamic Contact Theory of Lubrication,” (in Russian) Izv. Akad. Nauk SSSR (OTN), 2, p. 209.
20.
Sherman
,
W. F.
,
1980
, “
Bond Anharmonicities, Gruneisen Parameters and Pressure-Induced Frequency Shifts
,”
J. Phys. C
,
13
, No.
25
, pp.
4601
4613
.
21.
Etters, R. D., and Helmy, A. A., 1981, Physics of Solids Under High Pressure, J. S. Schilling and R. N. Shelton, eds., North-Holland Publishing Company, Amsterdam.
22.
Whalley
,
E.
,
Lavergne
,
A.
, and
Wong
,
P. T. T.
,
1976
, “
Hydrostatic Optical Cell with Glass Windows for 25 Kilobars
,”
Rev. Sci. Instrum.
,
47
, No.
7
, pp.
845
848
.
23.
Laplant
,
F.
,
Hutchinson
,
E. J.
, and
Ben-Amotz
,
D.
,
1997
, “
Raman Measurements of Localized Pressure Variations in Lubricants Above the Glass Transition Pressure
,”
ASME J. Tribol.
,
119
, pp.
817
822
.
24.
Bezot
,
P.
,
Hesse-Bezot
,
C.
,
Berthe
,
D.
,
Dalmaz
,
G.
, and
Vergne
,
P.
,
1986
, “
Viscoelastic Parameters of 5P4E as a Function of Pressure and Temperature by Light Scattering Technique
,”
ASME J. Tribol.
,
108
, pp.
579
583
.
25.
Hertz
,
H.
,
1882
, “
U¨ber die Beru¨hrung fester elastischer Ko¨rper,” (On the Contact of Elastic Solids
),
J. reine und angewandte Mathematik
,
92
, pp.
156
171
.
26.
Yasutomi
,
S.
,
Bair
,
S.
, and
Winer
,
W. O.
,
1984
, “
An Application of a Free-Volume Model to Lubricant Rheology (I): Dependence on Temperature and Pressure
,”
ASME J. Tribol.
,
106
, No.
2
, pp.
291
302
.
27.
Smeeth
,
M.
, and
Spikes
,
H. A.
,
1997
, “
Central and Minimum Elastohydrodynamic Film Thickness at High Contact Pressure
,”
ASME J. Tribol.
,
119
, pp.
291
296
.
28.
Krupka
,
I.
,
Hartl
,
M.
,
Poliscuk
,
R.
, and
Liska
,
M.
,
2000
, “
Experimental Study of Central and Minimum Elastohydrodynamic Film Thickness by Colorimetric Interferometry Technique
,”
Tribol. Trans.
,
43
, No.
4
, pp.
611
618
.
29.
Venner
,
C. H.
, and
ten Napel
,
W. E.
,
1992
, “
Multilevel Solution of the Elastohydrodynamically Lubricated Circular Contact Problem. Part 2: Smooth Surface Results
,”
Wear
,
152
, pp.
369
381
.
30.
Chevalier, F., 1996, “Mode´lisation des Conditions d’Alimentation dans les Contacts Elastohydrodynamiques Ponctuels,” (in French), Ph.D. thesis, INSA de Lyon, n ° 96ISAL0124.
You do not currently have access to this content.