How to simulate two physics field: e.g. Solid Mechanics and Electrostatics

Hi ,

I have a simulation about two physics field, that is, solid mechanics and electrostatics.

In my model, there are two parallel plates. I give a force or pressure on one plate, then caculate the capacitance. But to my surprise , the deformation doesn't change the capacitance which is the same with that never giving a force. It seems that the two physical fields run separately.

Any suggestion?

Thank you,

Qize,