Asperities Friction Review

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Asperities Friction Review

Asperities. Regardless of how smooth a surface may appear, it has many small irregularities called asperities. In cases where a surface is extremely rough, the contacting points are significant, but when the surface is fairly smooth, the contacting points have a very modest effect. The real or true surface area refers to the area of the points in direct contact. This area is considerably less than the apparent geometric area.

Friction is also proportional to the size of the asperities, so larger asperities result in increased friction and vice versa. This has resulted in the development of nearly frictionless materials with minuscule asperities.