Multiphysics Simulation of a Coupled Electrostatic Structural Analysis of a Collapsing Capacitor - ProductGuy2/Multiphysics-welding-examples GitHub Wiki

This example describes the use of coupled electrostatic structural analysis in Marc. In this analysis type, the Coulomb force, the force between charged bodies, links the electrostatic part to the structural part, and the deformation influences the electrostatic field. This is a weak coupling where, in the first pass, the electrostatic field is computed and the corresponding Coulomb forces are calculated. In the next pass, the structural response is evaluated, such that the Coulomb forces are treated as additional external forces. In a subsequent increment, the deformed state is used in the calculation of the electrostatic field. Since the electrostatic solution is a steady state solution, a time dependent problem will be solved as quasi-static during the electrostatic phase of the solution

Two parallel plates form a capacitor, that contains a charge (see Figure 1). One plate is fixed and electrically grounded, while the other plate is attached to a spring. Boundary conditions are chosen so that the plate connected to the spring can only move perpendicular to the fixed plate. Then, when this plate is loaded with charge, it will move toward the fixed plate. The charge is chosen as the applied load instead of potential since with increasing charge at a certain moment the potential will decrease as shown later in the results. Since the two plates are circular, an axisymmetric analysis will be performed. Air, both between the two plates and outside the plates, is taken into account to get a good representation of the electrostatic field. The air is only active in the electrostatic pass. The position of the nodes of the air region "contacting" the plates is updated based on the displacements of the plates. In order to avoid getting badly shaped elements due to the motion of the free plate, a region of air surrounding the plates is periodically remeshed.

See capacitor.proc in the repo