Discussion Forum

Hi COMSOL Forums,

I'm currently working on a simulation of capacitors with structured PDMS as a dielectric. I want to model the change in capacitance with a change in boundary load/pressure. My current model assumes that the top boundary of the PDMS has an applied voltage and applied boundary load. At the bottom of the film, there is a silicon film which acts as ground and a rigid base. The structure for the PDMS film I have currently selected is a triangular shape.

I have the mechanics portion of the simulation solved. I am using a stationary study and sweeping boundary loads. The geometry is constructed as an assembly. The deformation is modelled using contact-pair & solid mechanics assuming/forcing linear strains. (Currently, I do not have the non-linear mechanics package.) The deformation of the dielectric under pressure can be seen clearly and is quite large. The side walls of the triangle should come into contact with the base. I have also been able to successfully couple electrostatics in these domains. The simulation only takes into account the PDMS and silicon film but doesn’t include the vacuum/air surrounding the structure.

I would like to know add a vacuum/air environment in the remaining space between the PDMS and base. I have tried adding a deformed mesh to the remaining space but my solution does not converge. I'm not sure how I can couple the physics and deforming mesh together. Does anyone know what may be causing my problem and a possible solution?

Please let me know if what I am saying is unclear.

Thanks for your time and help, Michael