A Simple Mechanism for the Friction of Solid Metallic Bodies

A SIMPLE BASIC MECHANISM FOR THE FRICTION OF SOLID METALLIC BODIES 

The treatment o friction in the preceding chapter was primarily phenomenological, with emphasis on the observation and measurement of frictional behavior. In this chapter our inquiry will be directed toward the basic mechanisms of friction, particularly how the properties of solid surfaces and the conditions of sliding govern observable friction phenomena. 

The frictional behavior we are concerned with is a consequence of rubbing contact and involves the interaction of surfaces. Real surfaces are neither geometrically nor molecularly smooth. Discussion of the complexities of contact theory and their influence on rubbing behavior is the subject of Chapter 12. But even a simple treatment of the basic theory of friction involves the role of surface structure. 

Bowden and Tabor [1] describe the application of electrical resistance to the study of the contact of metallic surfaces. Two pairs of 

To make Eqn 8-1 useful in a physical sense we must answer the following questions (a) How many individual asperities are in contact to add up to the area A (b) What are the sizes of the asperity contacts Let us assume there are n asperities, all the same size and all situated at the same level in the nominal surface of the solid. The area A is then 

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