The Influence of Thermal Expansion and Plastic Deformation on a Thermo-Electro Mechanical Spherical Asperity Contact

Electrical contacts are expected to be influenced by coupled thermo-electro mechanical mechanisms. In this paper a single spherical asperity contact has been investigated with a coupled finite element thermo-electro mechanical approach. Thermo-electro mechanical behavior of a sphere in contact with a block has been analyzed while focusing on the effect of plastic deformation and thermal expansion. A finite element model is developed to analyze different cases and various parameters. Stress distribution, voltage drop and temperature profile have been presented. Results suggest that the thermal expansion influences the contact resistance significantly only for cases where the interferences are small. The thermal expansion decreases the contact resistance at a given interference, probably by effectively increasing the contact force. A non-dimensional parameter is derived to predict whether or not the influence of thermal expansion is important on an electrical contact.