On the state and severity of frictional sliding contacts between nominally flat metallic surfaces

Abstract

This paper develops and uses an analytically traceable model to study the state and severity of frictional contacts between nominally flat surfaces of elastic-perfectly-plastic materials. The state and severity of the contact is characterized by four area-of-contact variables. They include the real area of contact, the portion of the real area of contact in full plastic deformation, the portion of the real area of contact with high interfacial shear stresses, and the percentage increase of the real area of contact due to the friction-induced junction growth. Problems are studied ranging from very elastic to very plastic contacts under good-to-poor boundary-lubrication conditions. Dimensionless results are presented in a two-dimensional parameter space of the surface plasticity index and a system friction coefficient. Judged by these dimensionless results, the state and severity of the frictional contact is primarily governed by two model parameters: the plasticity index and the coefficient of friction. It is fairly insensitive to other system parameters such as the applied normal load and height distribution of surface asperities. The results may shed some lights on surface run-in, system operations, and possible friction instability of the tribo-system.

Keywords

frictional contact interfacial shear stress junction growth asperity plasticity index coefficient of friction

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References

Zhang

Chang

Webster

M. N.

Jackson

‘Effects of friction on the contact and deformation behavior in sliding asperity contacts’

Tribol. Trans. 46 (2003): 514–521

Greenwood

J. A.

Williamson

J. B. P.

‘Contact of nominally flat surfaces’

Proc. R. Soc. Ser. A 295 (1966): 300–319

Tabor

‘Junction growth in metallic friction: The role of combined stresses and surface contamination’

Proc. R. Soc. Ser. A. 251 (1959): 378–393

Chang

‘Modeling of asperity collisions and their effects in a frictionless sliding contact of nominally flat metallic surfaces’

ASME J. Tribol. 130 (2008): 7

Chang

Zhang

‘A mathematical model for frictional elastic-plastic sphere-on-flat contacts at sliding incipient’

ASME J. Appl. Mech. 74 (2006): 100–106

Johnson

K. L.

Contact mechanics (Cambridge: Cambridge University Press 1985)

Briscoe

B. J.

Tabor

‘Rheology of thin organic films’

ASLE Trans. 17 (1973): 158–165

Briscoe

B. J.

Scrutton

Willis

R. F.

‘The shear strength of thin lubricant films’

Proc. R. Soc. Ser. A 333 (1973): 99–114

Parker

R. C.

Hatch

‘The static coefficient of friction and the area of contact’

Proc. Phys. Soc. Ser. B 63 (1950): 185–197

10.

Bowden

F. P.

Young

J. E.

‘Friction of clean metals and the influence of adsorbed films’

Proc. R. Soc. Ser. A 208 (1951): 311–325

11.

Kayaba

Kato

‘Theoretical analysis of junction growth’ Technology reports, Tohoku University, 1978, vol. 43, pp. 1–10.

12.

Nayak

P. R.

‘Random process model of rough surface’

ASME J. Lubr. Technol. 93 (1971): 398–407

13.

McCool

J. I.

‘Comparison of models for the contact of rough surfaces’

Wear 107 (1986): 37–60

14.

Greenwood

J. A.

‘A simplified elliptic model of rough surface contact’

Wear 261 (2006): 191–200

15.

Chang

Zhang

‘On the two points of views of plastically deformed asperity contacts with friction loading’

Proc. IMechE, Part J: J. Engineering Tribology 219 (13) (2005): 201-208 DOI: 10.1243/135065005X33883

16.

McCool

J. I.

‘Extending the capability of the greenwood Williamson microcontact model’

ASME J. Tribol. 122 (2000): 496–502