The responses of MEMS actuators and switches immersed in fluids differ from those in a vacuum. Fluid inertia and viscosity delay the switch response in opening and closing, and fluid viscosity causes energy losses (squeeze film damping).
We developed multiphysics models of varying complexity to investigate the response of MEMS switches. Our models included coupled electrostatic-fluid-structure interaction that explicitly captured the electrostatic field, the resulting forces on the switch, the motion of the fluid as it moved in and out of the switch, and the contact interaction between the switch and base.
We also developed simpler models that approximately accounted for the electrostatic field or the fluid motion. We used the models to investigate the effect of the fluid on the switch response time, oscillation, and energy losses.