Numerical Study of Asperity Distribution in an Electrical Contact

Abstract

Electrical contacts consists of parts where the surfaces are in contact and where the actual physical contact occur just in a few contact asperity points scattered over the whole apparent contact area. Through these contact spots between the mating bodies the mechanical load and the electric current is transmitted. Often a soft coating is used to enlarge the real contact area. Modeling the mechanical stress on the contacting material includes nonlinear effects of the electric conduction and heat generation as well as the actual mechanical contact of the asperities. A finite element model has been used to study the multiphysics of thermo electromechanical phenomena when two surface asperities are in contact. A three dimensional model describing the asperity size, distribution, normal and shear loads and material property. With geometry of hexagonal shape and symmetrical boundary conditions a larger contact surface of similar roughness can be described.