The influence of multiscale surface roughness on contact mechanics using finite element modeling: Applied to a Au-coated CNT composite electrical contact surface

It has been shown that a gold-coated multi-walled carbon nanotube (Au/MWCNT) composite can improve the lifetime of electrical contacts significantly in low current switching applications. The composite surface with gold sputtered on vertically aligned CNTs, shows two levels of surface roughness that causes a variation of contact resistance across the surface. In this study a mathematical surface model is developed to generate surfaces with multi-scale roughness. A finite element contact model is then developed to determine the contact area using the generated surface data. The influence of the multi-scale roughness and waviness is then applied to the contact mechanics of Au/CNT composite, and shows that there is a significant variation in predicted contact area across the surface, thus reflecting a variation in contact resistance. The surface model is shown to be a useful tool to predict the contact resistance variation with the multi-scale roughness.