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MEMS diaphragm electromechanic simulation: mesh not moving!
Posted 15 avr. 2010, 05:54 UTC−4 3 Replies
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I'm trying to simulate the deformation of a diaphragm due to electrostatic attraction with an underlying surface. I'm using the electrostatics, structural mechanics and moving mesh (ALE) modules. But: when I apply a voltage between the diaphragm and the surface the diaphragm does not move at all, even if I can plot the force acting on it in the plots! The force should be enough (and in fact it is when I apply it directly as a mechanical load).
What could be the problem? I'm attaching the model so you can check what I'm talking about.
Thank you,
Pippo
What could be the problem? I'm attaching the model so you can check what I'm talking about.
Thank you,
Pippo
Attachments:
3 Replies Last Post 17 avr. 2010, 15:51 UTC−4
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Posted:
1 decade ago
Hi
your model is not that easy to understand, I had to turn off the surface rendering to better see it. If I understand correctly what puzzles me is that your ALE surface 9,10,18,25 is supposed to move along u,v,w, but it's attached to the lower (-Z) surface area that si fixed.
It looks like you have overconstrined your ALE, but I'm not 100% sure I have got right all the details of you model
Now I do not have enought time to go into details of your model, mixing 3 physics requires some undestanding and study, buzt I would suggest you start with a 2D axi case and a pure Z motion, this is quicker to set up and easier to debug, and then you port it to 3D
Have fun Comsoling
Ivar
your model is not that easy to understand, I had to turn off the surface rendering to better see it. If I understand correctly what puzzles me is that your ALE surface 9,10,18,25 is supposed to move along u,v,w, but it's attached to the lower (-Z) surface area that si fixed.
It looks like you have overconstrined your ALE, but I'm not 100% sure I have got right all the details of you model
Now I do not have enought time to go into details of your model, mixing 3 physics requires some undestanding and study, buzt I would suggest you start with a 2D axi case and a pure Z motion, this is quicker to set up and easier to debug, and then you port it to 3D
Have fun Comsoling
Ivar
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Posted:
1 decade ago
I've followed your advice and simulated the thing on a simplified 2d axially simmetric model for now.
Do you know how can I plot the results in 3D?
Do you know how can I plot the results in 3D?
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Posted:
1 decade ago
Hi
for many cases this is possible, but the technique requires some work, there are a few examples in the doc, you need to use the "extrusion coupling variables", check the doc.
To be honest, I find it too long so I hardly use this approach as its only for a visualisation (in my cases so far, but can be also successfully used to port i.e. initial conditions to 3D) and the 2D is anyhow sufficient for me.
But once a model is running nicely in 2D, I often make it fully in 3D, with a coarser mesh mostly, otherwise I would have to wait a year for the PC to finish, for global check and for the presentation, when ttat is important.
Have fun Comsoling
Ivar
for many cases this is possible, but the technique requires some work, there are a few examples in the doc, you need to use the "extrusion coupling variables", check the doc.
To be honest, I find it too long so I hardly use this approach as its only for a visualisation (in my cases so far, but can be also successfully used to port i.e. initial conditions to 3D) and the 2D is anyhow sufficient for me.
But once a model is running nicely in 2D, I often make it fully in 3D, with a coarser mesh mostly, otherwise I would have to wait a year for the PC to finish, for global check and for the presentation, when ttat is important.
Have fun Comsoling
Ivar