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Volume cavity

Posted Jan 11, 2023, 3:22 p.m. EST Geometry, Modeling Tools & Definitions, Results & Visualization Version 6.1 2 Replies

Y KO
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Hello

I am trying to calcuate volume cavity. I have a model with enclosed space on 2D axial symmety component. I assigned parapmetric sweep to increase pressure in the space. The pressress are 0, 20, 360 psi. I assigned definations " Areaint(-z*solid.nz)" on the boundaries in the space.

By using global evaluations, I got the volumes of the three different pressures. However, all the volume values are the same as the initial volume without pressure applied.

How can I get the correct volumes for the three different pressures.?

2 Replies Last Post Jan 12, 2023, 1:05 p.m. EST
Henrik Sönnerlind COMSOL Employee

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Posted: 2 years ago Jan 12, 2023, 9:05 a.m. EST

In order to do this kind of evaluation, you must use a geometrically nonlinear analysis. If not, there is no difference between the undeformed Z and the deformed z.

As an alternative, you could write Areaint(-(Z+w)*solid.nZ). It will give an approximative value, since only the coordinate, but not the normal direction is updated. Thus, it will work reasonably as long as rotations are small.

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Henrik Sönnerlind
COMSOL
In order to do this kind of evaluation, you must use a geometrically nonlinear analysis. If not, there is no difference between the undeformed Z and the deformed z. As an alternative, you could write Areaint(-(Z+w)\*solid.nZ). It will give an approximative value, since only the coordinate, but not the normal direction is updated. Thus, it will work reasonably as long as rotations are small.
Y Ko
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Posted: 2 years ago Jan 12, 2023, 1:05 p.m. EST
Updated: 1 year ago Feb 5, 2023, 12:27 p.m. EST

Hello Henrik

Areaint(-(Z+w)solid.nZ) works ! Thank you so much. And I also tried "geometrically nonlinear analysis". I could get different volume values for the different pressures. However, the displacements for the analysis were significantly differnt from "linear anaylysis"

In this case, I don't know what anaylsis is giving me the correct results. Would you mind letting me know about what to do with "geometrically nonlinear analysis". ? I just simply checked "Include geometic nonlinearity". According to this link below.

I attached my file.

https://www.comsol.com/blogs/what-is-geometric-nonlinearity/

Hello Henrik Areaint(-(Z+w)solid.nZ) works ! Thank you so much. And I also tried "geometrically nonlinear analysis". I could get different volume values for the different pressures. However, the displacements for the analysis were significantly differnt from "linear anaylysis" In this case, I don't know what anaylsis is giving me the correct results. Would you mind letting me know about what to do with "geometrically nonlinear analysis". ? I just simply checked "Include geometic nonlinearity". According to this link below. I attached my file. https://www.comsol.com/blogs/what-is-geometric-nonlinearity/

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