Publications

Anomalies in the theory of viscous energy losses due to shear in rotational MEMS resonators

Dohner, Jeffrey L.; Dohner, Jeffrey L.; Jenkins, Mark W.; Walsh, Timothy W.; Rhodes, Kelly A.

In this paper, the effect of viscous wave motion on a micro rotational resonator is discussed. This work shows the inadequacy of developing theory to represent energy losses due to shear motion in air. Existing theory predicts Newtonian losses with little slip at the interface. Nevertheless, experiments showed less effect due to Newtonian losses and elevated levels of slip for small gaps. Values of damping were much less than expected. Novel closed form solutions for the response of components are presented. The stiffness of the resonator is derived using Castigliano's theorem, and viscous fluid motion above and below the resonator is derived using a wave approach. Analytical results are compared with experimental results to determine the utility of existing theory. It was found that existing macro and molecular theory is inadequate to describes measured responses.