Erik Kostson
Ansys Employee

Did not say that, I said that I have not seen any examples of this - you might still be able to do what you want, but you would need to find out by trying yourself (so static dc bias followed by harmonic).

Also do you use solid226 for the internal airgap and to get the capacitive force on the membrane?
I would also say that the Lamb waves are mostly excited by the two support legs on either side of the membrane thus transferring the vibrations into the substrate.
All the best of luck -
let us know how it goes, and how you progress.