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Modeling resonant pressure sensor in COMSOL 3.5

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Dear All,

I am trying to model a simple resonant pressure sensor consisting of a rectangular beam suspended in the cavity formed on the top of the diaphragm. Pls refer to the figure in the attachment. Currently I am not so concerned with the beam excitation and want to only check the change in the resonant frequency of the beam with the pressure applied to the bottom of the diaphragm.

Do I need a moving mesh ?

I have tried two approaches.

1. I have taken 2 stress-strain models - one for the diaphragm (static linear mode) and one for the beam(Eigenfrequency mode). But in this case how do I transfer the stresses developed on the diaphragm on to the end face of the beam?

2. The other approach is to define 2 stress strain models as before and a moving mesh for the suspended beam and use the deformed mesh to solve for eigenfrequency. But I'm unable to get the eigen frrequency.

Can anyone give me a detailed procedure to model the sensor?

Thanks in advance,

Best regards,
Ashwin Simha.


1 Reply Last Post Jan 25, 2011, 3:02 a.m. EST
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago Jan 25, 2011, 3:02 a.m. EST
Hi

if it "stress stiffening" you are looking after, then in v3.5 you need to use matlab, to initiate a spatial solver, to stress your model, and then use that as a starting point for the egenvalue solver, as the latter linearizes the model.

in V4 you can link these sovler sequences as stated without the need for passing through matlab

--
Good luck
Ivar
Hi if it "stress stiffening" you are looking after, then in v3.5 you need to use matlab, to initiate a spatial solver, to stress your model, and then use that as a starting point for the egenvalue solver, as the latter linearizes the model. in V4 you can link these sovler sequences as stated without the need for passing through matlab -- Good luck Ivar

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