A Comparison of the Predictions of a Finite Element Model and Multiscale Model for a Rough MEMS Electrical Contact

Abstract

Rough surface contact is difficult to model effectively due to multiple scales of detail that need to be considered. This work presents the results of a multiscale rough surface contact model in comparison to a finite element based deterministic model for the electrical contact of a MEMS microswitch. The real area of contact and electrical contact resistance are predicted and compared as a function of normal load. The results show good quantitative and qualitative correlation between the two methods. As expected, the contact area increases nominally linearly with load, while the contact resistance decreases with load. It is notable though that the contact pressure is up to 16% higher than the hardness (2.8 times yield strength), and could be even higher for other surfaces.