The elastic-plastic contact between a deformable sphere and a rigid flat during presliding is studied experimentally. Measurements of friction force and contact area are done in real time along with an accurate identification of the instant of sliding inception. The static friction force and relative tangential displacement are investigated over a wide range of normal preloads for several sphere materials and diameters. Different behavior of the static friction is observed in the elastic and in the elastic-plastic regimes of sphere deformation. It is found that at low normal loads, the static friction coefficient depends on the normal load in breach of the classical laws of friction. The presliding displacement is found to be less than 5% of the contact diameter, and the interface mean shear stress at sliding inception is found to be slightly below the shear strength of the sphere material. Good correlation is found between the present experimental results and a recent theoretical model in the elastic-plastic regime of deformation.
Issue Section:
Contact Mechanics
Keywords:
static friction,
presliding,
elastic-plastic contact,
spherical contact,
in situ real-time measurement,
elastic deformation,
mechanical contact,
plastic deformation,
shear strength,
sliding friction
Topics:
Deformation,
Displacement,
Friction,
Stiction,
Stress,
Steel,
Sapphire,
Shear strength,
Copper,
Tangential loading,
Adhesives
1.
Tichy
, J. A.
, and Meyer
, D. M.
, 2000, “Review of Solid Mechanics in Tribology
,” Int. J. Solids Struct.
0020-7683, 37
, pp. 391
–400
.2.
Blau
, P. J.
, 2001, “The Significance and Use of the Friction Coefficient
,” Tribol. Int.
0301-679X, 34
, pp. 585
–591
.3.
Urbakh
, M.
, Klafter
, J.
, Gourdon
, D.
, and Israelechvili
, J.
, 2004, “The Nonlinear Nature of Friction
,” Nature (London)
0028-0836, 430
, pp. 525
–528
.4.
Chang
, W. R.
, Etsion
, I.
, and Bogy
, D. B.
, 1988, “Static Friction Coefficient Model for Metallic Rough Surfaces
,” ASME J. Tribol.
0742-4787, 110
, pp. 57
–63
.5.
Kogut
, L.
, and Etsion
, I.
, 2003, “A Semi-Analytical Solution for the Sliding Inception of a Spherical Contact
,” ASME J. Tribol.
0742-4787, 125
, pp. 499
–506
.6.
Brizmer
, V.
, Kligerman
, Y.
, and Etsion
, I.
, 2007, “Elastic-Plastic Spherical Contact Under Combined Normal and Tangential Loading in Full Stick
,” Tribol. Lett.
1023-8883, 25
, pp. 61
–70
.7.
Chang
, L.
, and Zhang
, H.
, 2007, “A Mathematical Model for Frictional Elastic-Plastic Sphere-on-Flat Contacts at Sliding Incipient
,” ASME J. Appl. Mech.
0021-8936, 74
, pp. 100
–106
.8.
Parker
, R. C.
, and Hatch
, D.
, 1950, “The Static Coefficient of Friction and the Area of Contact
,” Proc. Phys. Soc. London, Sect. B
0370-1301, 63
, pp. 185
–197
.9.
McFarlane
, J. S.
, and Tabor
, D.
, 1950, “Relation Between Fiction and Adhesion
,” Proc. R. Soc. London, Ser. A
1364-5021, 202
, pp. 244
–253
.10.
Courtney-Pratt
, J. S.
, and Eisner
, E.
, 1957, “The Effect of a Tangential Force on the Contact of Metallic Bodies
,” Proc. R. Soc. London, Ser. A
1364-5021, 238
, pp. 529
–549
.11.
Constantinou
, C. P.
, and Chaudhri
, M. M.
, 1989, “Optical Observations of “Junction Growth” in Asperities of Copper, Aluminium, PTFE and Nylon Under Combined Normal and Tangential Stresses
,” J. Mater. Sci.
0022-2461, 24
, pp. 4279
–4292
.12.
Etsion
, I.
, Levinson
, O.
, Halperin
, G.
, and Varenberg
, M.
, 2005, “Experimental Investigation of the Elastic-Plastic Contact Area and Static Friction of a Sphere on Flat
,” ASME J. Tribol.
0742-4787, 127
, pp. 47
–50
.13.
Ovcharenko
, A.
, Halperin
, G.
, Etsion
, I.
, and Varenberg
, M.
, 2006, “A Novel Test Rig for In Situ and Real Time Optical Measurement of the Contact Area Evolution During Pre-Sliding of a Spherical Contact
,” Tribol. Lett.
1023-8883, 23
, pp. 55
–63
.14.
Brizmer
, V.
, Kligerman
, Y.
, and Etsion
, I.
, 2006, “The Effect of Contact Conditions and Material Properties on the Elasticity Terminus of a Spherical Contact
,” Int. J. Solids Struct.
0020-7683, 43
, pp. 5736
–5749
.15.
Ovcharenko
, A.
, Halperin
, G.
, and Etsion
, I.
, “In Situ and Real Time Optical Investigation of Junction Growth in Spherical Elastic-Plastic Contact
,” Wear
0043-1648, in press, doi: 10.1016/j.wear, 2007.08.009.16.
Bowden
, F. P.
, and Tabor
, D.
, 1950, The Friction and Lubrication of Solids
, Oxford University Press
, London, Great Britain
, Chap. VII.17.
Rabinowicz
, E.
, 1965, Friction and Wear of Materials
, Wiley
, New York
, Chap. 4.6.18.
Brizmer
, V.
, Zait
, Y.
, Kligerman
, Y.
, and Etsion
, I.
, 2006, “The Effect of Contact Conditions and Material Properties on Elastic-Plastic Spherical Contact
,” J. Mech. Mater. Struct.
1559-3959, 1
, pp. 865
–879
.19.
Ovcharenko
, A.
, Halperin
, G.
, Verberne
, G.
, and Etsion
, I.
, 2007, “In Situ Investigation of the Contact Area in Elastic-Plastic Spherical Contact During Loading-Unloading
,” Tribol. Lett.
1023-8883, 25
, pp. 153
–160
.20.
Kagami
, J.
, Yamada
, K.
, and Hatazawa
, T.
, 1983, “Contact Between a Sphere and Rough Plates
,” Wear
0043-1648, 87
, pp. 93
–105
.21.
Greenwood
, J. A.
, Johnson
, K. L.
, and Matsubara
, E.
, 1984, “A Surface Roughness Parameter in Hertz Contact
,” Wear
0043-1648, 100
, pp. 47
–57
.22.
Jamari
, J.
, and Schipper
, D. J.
, 2007, “Deformation Due to Contact Between a Rough Surface and a Smooth Ball
,” Wear
0043-1648, 262
, pp. 138
–145
.23.
Kogut
, L.
, and Etsion
, I.
, 2000, “Electrical Conductivity and Friction Force Estimation in Compliant Electrical Connectors
,” Tribol. Trans.
1040-2004, 43
, pp. 816
–822
.Copyright © 2008
by American Society of Mechanical Engineers
You do not currently have access to this content.
