Carbon to cast iron electrical contact resistance constitutive model for finite element analysis

Abstract

The electrical contact resistance at the interface between two materials is often an unknown when modelling certain processes, such as the anodes and cathodes in Hall–Héroult cells or the spot welding of sheet metal. In this paper, a 2D axisymmetric weakly coupled thermo-electro-mechanical finite element methodology built in the commercial code ANSYS is presented. It allows the generation of Joule heat directly at the interface, the precise representation of the contact areas as well as the testing of different contact resistance models. Using existing experimental results of industrial carbon and steel cylinders in contact at different temperatures, a novel phenomenological constitutive law for electrical contact resistance was developed. This experiment was repeated at room temperature with Alcoa-Lauralco carbon and cast iron cylinders, and the 2D finite element model was used to validate and calibrate the constitutive law. An excellent agreement was found between the model predictions and the new experimental data.