Hello,

I am designing a MEMS device that is essentially a stepper motor that is rotated with an electrostatic torque. It is monolithic, and a series of beams in series are deformed giving a cumulative rotation of the outermost ring (rotor). The electrostatic rotation mechanism and design are based on previous work demonstrated nicely at the end of the video linked below. Voltage is sent in 3 phases to alternating teeth, which act as parallel plate capacitors and pull the motor in a rotational motion in steps. I have not modeled the teeth and electrostatics because I assume that would be way too complicated, in the end it is just providing a rotational torque.

I have an initial simulation set up but I am totally new to ANSYS and do not know how to set up the electrostatic torque (moment) to be physically realistic. The main setting I am unsure of is behavior, I initially chose deformable because the "rotor" can in fact deform, but the "stator" providing the torque via electrostatics will not deform. I wonder if rigid or coupled is more realistic. Also, I have turned large deflections on.

I have gotten the solution to converge for smaller torques than would actually be applied (30,000 uN*um as opposed to ~90,000 uN*um) and with 20 substeps, but once again I don't know much about substeps and if that physically represents what is actually happening. 

Other info: there is a fixed support to a silicon substrate and I am also including gravity since it will be standing upright (eventually there will be a cylindrical pin coming out from the center of the device, which the main thing we want to rotate). The pin will be small so I believe deformation due to gravity will be negligible.

I am primarily interested in rotational range for a given voltage (i.e. moment), Von-Mises stress under deformation, and shift of the the center point. I have found a non-student license through my workplace, so I do not have the limitations of the student version.

Any help to make this simulation physically realistic would be really, really appreciated!