Micro‐slip test equipment for point contacts

Abstract

AbstractMicro‐slip can be characterised as local slip in a contact. Test equipment has been developed to study the phenomenon in point contacts. Although the equipment is designed for any point contact, the surface configuration presented here is a sphere against a flat. With the equipment, it is possible to measure accurately forces and displacements in both the normal and the tangential direction of the contact. Three‐dimensional surface topography measurements of the contact surfaces can also be made before and after each test.A series of experiments has been carried out in which normal load, surface roughness, material combination, and lubrication were varied. The general experience gathered from the tests was that the equipment is accurate enough for very small contacts and is easy to use. The test results presented in this paper show tangential and normal displacement and tangential load for contacts subjected to small macro displacements, both undirectional and oscillating. The degree of plastic deformation in a contact is also shown for some tests.