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Deflection of Thin Membrane Under Pressure

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I am working on modeling the deflection of a thin, circular parylene membrane with an attached cylindrical silicon boss (see attached file). I am using a 2D-axisymmetric model with the Solid Mechanics module.

I am getting results very different from those I expect. I have verified all the material properties and geometric parameters but cannot figure out what's wrong. I am solving for deformation in the z-direction and getting on the order of 2mm when I should be getting around 50 um (expected number is from experimental results and an ANSYS model).

The parylene membrane is fixed at its outermost edge and has a pressure of 100 mmHg pushing up on it, all of which I believe I modeled in the same way as the ANSYS model. The reason I'm trying to make a COMSOL model now is so that I can include the initial stress (to model the residual stress in the parylene). I solved the model without the initial stress in COMSOL and still got an unrealistic answer.

Can you offer any insight as to what I'm doing wrong?


0 Replies Last Post 03.08.2011, 15:29 GMT-4
COMSOL Moderator

Hello Ravi Shah

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