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Force between a parallel plate capacitor
Posted 23 avr. 2010, 15:12 UTC−4 2 Replies
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Hi,
I am very new to comsol. that being said, I have managed to model my problem in 3D, mesh it and view the results.
I am attempting to measure the electrostatic force between an AFM tip and a grounded sample. Before I do this I want to verify that my method corresponds with the theoretical result. To this end, I have modelled a parallel plate capacitor (a flat box with appropriate boundary conditions). The box is 1e-3 x 1e-3 x 1e-6 [m] with the top surface set to 1 [v] and the bottom surface grounded.
I would like to calculate the force one plate exerts on an other. Theoretically, the result should be:
F=V^2*permittivity*Area / ( 2*separation^2)
How would one set up post processing to obtain this solution?
I was thinking that the total charge on a place could be found by a surface integral of D.ds, but this would give you a Force field - not a total Force.
Thanks, all help would be much appreciated,
E
I am very new to comsol. that being said, I have managed to model my problem in 3D, mesh it and view the results.
I am attempting to measure the electrostatic force between an AFM tip and a grounded sample. Before I do this I want to verify that my method corresponds with the theoretical result. To this end, I have modelled a parallel plate capacitor (a flat box with appropriate boundary conditions). The box is 1e-3 x 1e-3 x 1e-6 [m] with the top surface set to 1 [v] and the bottom surface grounded.
I would like to calculate the force one plate exerts on an other. Theoretically, the result should be:
F=V^2*permittivity*Area / ( 2*separation^2)
How would one set up post processing to obtain this solution?
I was thinking that the total charge on a place could be found by a surface integral of D.ds, but this would give you a Force field - not a total Force.
Thanks, all help would be much appreciated,
E
2 Replies Last Post 7 mai 2010, 01:17 UTC−4
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Posted:
1 decade ago
Hi Anema,
Welcome to comsol community.
If I understand you right from your discription. I would suggest you to follow the 'cantilever beam' tutorial in MEMS model. In this tutorial they explain you to find the pull-in voltage using moving mesh method. But for your purpose you can use the same model, and see the deflection of cantliver for different applied voltages. Also, i would suggest to follow 2D model, as its faster and requires less computer resources.
Best of luck,
Dhwajal
Welcome to comsol community.
If I understand you right from your discription. I would suggest you to follow the 'cantilever beam' tutorial in MEMS model. In this tutorial they explain you to find the pull-in voltage using moving mesh method. But for your purpose you can use the same model, and see the deflection of cantliver for different applied voltages. Also, i would suggest to follow 2D model, as its faster and requires less computer resources.
Best of luck,
Dhwajal
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Posted:
1 decade ago
Hi,
I'm relatively a new user to COMSOL. I used a little bit of post processing to view results for equations like yours so I will make some suggestion based on what I have been using in my model. To begin with, you can write your equation in global expressions if it is not available in the application mode you are using. After you solve, under post processing you can select data display-> global. There you should be able to input the expression you used for force, say F. Computed results are shown in the results area at the bottom of your COMSOL window.
Hope this helps!
Rajesh.
I'm relatively a new user to COMSOL. I used a little bit of post processing to view results for equations like yours so I will make some suggestion based on what I have been using in my model. To begin with, you can write your equation in global expressions if it is not available in the application mode you are using. After you solve, under post processing you can select data display-> global. There you should be able to input the expression you used for force, say F. Computed results are shown in the results area at the bottom of your COMSOL window.
Hope this helps!
Rajesh.