On the Mechanism of Contact between Solid Surfaces : 3rd Report, The Number and the Distribution of Radii of Contact Points

Abstract

Assuming that the asperities on normally distributed surface are cones or pyramids the slopes of which depend on the surface roughness, the three dimensional number and the distribution of the radii of contact points are deduced theoretically. The results of the theoretical analyses are compared with the experimental results for the numbers and the distribution of the radii of contact points in the case of contact between two nominally flat metal surfaces prepared by sandpaper-finishing, sandblasting and grinding. Results seem to support the plausibility of the proposed theory. Moreover they show that over a wide load range the average radii of contact points are almost constant ; consequently the total contact area is increased mainly owing to the increase in the number of the contact points.