The development of a finite element contact model of a rough surface applied to a Au-coated carbon nanotube composite

Multi-walled carbon nanotubes (MWCNTs) coated surfaces have been developed to improve the lifetime of electrical contact of MEMS switches. However, little research has been done on the contact mechanics of the surfaces. The surfaces, usually gold coated, demonstrated a complex structure due to the gold penetrating into MWCNT and a much higher roughness than metal surfaces, with R_a in the order of 1-2 μm. This study is based on a finite element model of a bi-layered structure model for Au/MWCNT composite that includes the surface roughness. The goal is to build up a model much closer to real surfaces, and real surface data was used in the modeling. It is shown that it is only a few asperities making contact due to the roughness, and the contact area is much smaller than that of smooth surface.