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relation between eigen frequency and pressure
Posted 30 ott 2012, 14:27 GMT-4 MEMS & Nanotechnology, MEMS & Piezoelectric Devices Version 4.2 1 Reply
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we are currently doing a project on mems piezoresistive pressure sensor using comsol.... can you please tell how both eigen frequency and pressure are related to each other?
1 Reply Last Post 30 ott 2012, 14:38 GMT-4
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Posted:
1 decade ago
Hi
my first reaction is to say they are not related, as a pressure force is an external load and is ignored for an eigenfrequency analysis (by definition of the eigenfreuency solving sequence).
But if you want to study the stress stiffening that might have an influence on the material stiffness, hence change the eigenfrequency, then you need to do a coupled physics "loaded eigenfrequency" by first loading the system with your pressure load in a stationary solver case, then use that as the linearisation point (initial values) for the eigenfrequency solver case. This should give you the infleunce of the pressure on the material and the realetd stiffening change, hence eigenfrequency change. You might need to consider the non-linear geoemtry option depending on the load you are putting on your structure.
There should be some moel library, or model gallery cases illustrating this too, try a search ;)
--
Good luck
Ivar
my first reaction is to say they are not related, as a pressure force is an external load and is ignored for an eigenfrequency analysis (by definition of the eigenfreuency solving sequence).
But if you want to study the stress stiffening that might have an influence on the material stiffness, hence change the eigenfrequency, then you need to do a coupled physics "loaded eigenfrequency" by first loading the system with your pressure load in a stationary solver case, then use that as the linearisation point (initial values) for the eigenfrequency solver case. This should give you the infleunce of the pressure on the material and the realetd stiffening change, hence eigenfrequency change. You might need to consider the non-linear geoemtry option depending on the load you are putting on your structure.
There should be some moel library, or model gallery cases illustrating this too, try a search ;)
--
Good luck
Ivar