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Utilizing a deforming geometry in a capacitor model

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Greetings,

I am working on a model of a capacitive displacement sensor. The terminal plates remain fixed while the ground plate is allowed to displace. At the nominal position, there is an equal overlap between the terminals and ground plates, and at the maximum functional displacement there would be a 2x overlap on one terminal and 0x on the other.

I have attached a simplified model of this system. The baseline capacitances of both terminals to ground is 1.4 pF with fringing effects. When I apply a displacement to the ground plate such that it would change the overlap areas to 0.5x and 1.5x (ideally making the matrix output 0.7 pF and 2.1 pF), I get the same results for my capacitance matrix, even though I can verify that my ground plate has moved and the overlap area has changed significantly.

Interestingly if I move the ground plate down, reducing the gap, there is an appropriate change in capacitance, thus the mechanical motion is being transfered into the electrical calculations, however it appears to have no effect.

Has anyone attempted a model similar to this before, and were you able to find a way to have the capacitance change with overlap without simply rebuilding the geometry in the displaced configuration?

Regards, Alex



1 Reply Last Post 2018年12月12日 GMT-5 13:54
Edgar J. Kaiser Certified Consultant

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Posted: 5 years ago 2018年12月12日 GMT-5 13:54

Alex,

you will need to add a moving mesh, otherwise movements in the model will not couple back to the electric field.

Cheers Edgar

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Edgar J. Kaiser
emPhys Physical Technology
www.emphys.com
Alex, you will need to add a moving mesh, otherwise movements in the model will not couple back to the electric field. Cheers Edgar

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