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Symmetric meshing

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Dear all,

I'd like to learn if it is possible to have symmetry axis in mesh. I'm working on a 3D model, and the geometry is symmetric in both x and y axis. I'm studying on eigenfrequency analysis and I'd like the mesh to be symmetric in x-axis only.

To be more clear, I don't expect to see symmetric results for all mode shapes of course but when the mode shape is known to be symmetric by analytical means I want to see a more realistic illustration of it.

Thanks,
Utku

6 Replies Last Post Nov 25, 2017, 8:19 a.m. EST

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Posted: 9 years ago Apr 29, 2015, 7:47 p.m. EDT
This is a really good question. With another package I've used this would happen by meshing the half-structure, then reflecting the meshed structure to generate a new meshed structure where the mesh was thus guaranteed symmetric to numerical precision. Is it possible to reflect after meshing?
This is a really good question. With another package I've used this would happen by meshing the half-structure, then reflecting the meshed structure to generate a new meshed structure where the mesh was thus guaranteed symmetric to numerical precision. Is it possible to reflect after meshing?

Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 9 years ago Apr 30, 2015, 1:22 a.m. EDT
Hi

have you really checked all mesh options/sub-nodes ?

You have thereunder copy mesh with or without mirror functions, no ?
COMSOL add new features for each release, so "my way" is to regularly click on all sub nodes and check that I remember all options down to the last leaf

--
Good luck
Ivar
Hi have you really checked all mesh options/sub-nodes ? You have thereunder copy mesh with or without mirror functions, no ? COMSOL add new features for each release, so "my way" is to regularly click on all sub nodes and check that I remember all options down to the last leaf -- Good luck Ivar

Henrik Sönnerlind COMSOL Employee

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Posted: 9 years ago Apr 30, 2015, 9:10 a.m. EDT
Hi,

To be a little more specific:

1. First mesh one side.

2a) If the two domains which are symmetric have a common boundary, then it is sufficient to add a Copy Mesh or Copy Domain node in the mesh sequence. The mesh is automatically mirrored.

2b) If the who domains are disjoint, use a Copy Domain node, and add an Edge Map or Two-Point Map subnode to control the orientation of the copied mesh.

Regards,
Henrik
Hi, To be a little more specific: 1. First mesh one side. 2a) If the two domains which are symmetric have a common boundary, then it is sufficient to add a Copy Mesh or Copy Domain node in the mesh sequence. The mesh is automatically mirrored. 2b) If the who domains are disjoint, use a Copy Domain node, and add an Edge Map or Two-Point Map subnode to control the orientation of the copied mesh. Regards, Henrik

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Posted: 9 years ago Apr 30, 2015, 8:02 p.m. EDT
Hi,

Thank you all for your detailed replies. I haven't seen a 'mirror' node but I've seen copy domain node which I thought something different.

After I see your replies, I separated my 1 domain geometry into 2 symmetric domains and copy the mesh, it worked. Very quick and easy solution and the results are very satisfactory.

Thanks again,
Utku
Hi, Thank you all for your detailed replies. I haven't seen a 'mirror' node but I've seen copy domain node which I thought something different. After I see your replies, I separated my 1 domain geometry into 2 symmetric domains and copy the mesh, it worked. Very quick and easy solution and the results are very satisfactory. Thanks again, Utku

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Posted: 7 years ago Jul 19, 2017, 7:51 a.m. EDT
This works. However, when adding an additional size-node with geometric entity level 'boundary' to the common boundary, the copy operation does not work any longer. Instead, it gives the error message: "different number of edge elements". How can I solve this problem?
This works. However, when adding an additional size-node with geometric entity level 'boundary' to the common boundary, the copy operation does not work any longer. Instead, it gives the error message: "different number of edge elements". How can I solve this problem?

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Posted: 6 years ago Nov 25, 2017, 8:19 a.m. EST

Hi,

I have found another problem, i.e., if I put two domains together, which are exactly same, and share one same face, it seems I cannot use the 'copy domain' node? Do you have solutions

Thanks in advance.

HX

Hi, I have found another problem, i.e., if I put two domains together, which are exactly same, and share one same face, it seems I cannot use the 'copy domain' node? Do you have solutions Thanks in advance. HX

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