Theory of friction based on brittle fracture

Journal of Applied Physics
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Abstract

A theory of friction is presented that may be more applicable to geologic materials than the classic Bowden and Tabor theory. In the model, surfaces touch at the peaks of asperities and sliding occurs when the asperities fail by brittle fracture. The coefficient of friction, μ, was calculated from the strength of asperities of certain ideal shapes; for cone‐shaped asperities, μ is about 0.1 and for wedge‐shaped asperities, μ is about 0.15. For actual situations which seem close to the ideal model, observed μ was found to be very close to 0.1, even for materials such as quartz and calcite with widely differing strengths. If surface forces are present, the theory predicts that μ should decrease with load and that it should be higher in a vacuum than in air. In the presence of a fluid film between sliding surfaces, μ should depend on the area of the surfaces in contact. Both effects are observed. The character of wear particles produced during sliding and the way in which μ depends on normal load, roughness, and environment lend further support to the model of friction presented here.
Publication type Article
Publication Subtype Journal Article
Title Theory of friction based on brittle fracture
Series title Journal of Applied Physics
DOI 10.1063/1.1710026
Volume 38
Issue 7
Year Published 1967
Language English
Publisher AIP
Description 7 p.
First page 2928
Last page 2934
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