Discussion Forum

Nithin,

Usually I get this error when I have a model that has swept meshing combined with free tetrahedral meshing operations. In order for the faces of the tetrahedra (triangles) to be conformal to the faces of the prisms or hexahedra (quadrilaterals), you need to convert the quadrilateral faces into triangles. If this is not possible because of adjacent face constraints, I would back up and consider if you might need to mesh everything using a free tetrahedral operations. Or, use partitioning of your geometry to slice up your domains to make them more appropriate for efficient meshing.

Hope that helps you get on the right track. If you want, you could try posting your mph file and seeing if someone could help when they have a look at your actual geometry and mesh sequence.

Regards,
Josh Thomas

Hi

in the mesh options you have "convert mesh" which splits 3D bricks into tets, or 2D quad into tri mesh elements

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Good luck
Ivar

Ivar,

I used the convert meshing, but the mesh still failed to generate. I received an error that said "Failed to respect boundary element edge on geometry face. Any suggestions on how to resolve this problem?

Thank you,
Ian

Hi,

Maybe you can upload your mesh if you want some more concrete help

Best regards

Julien

Hi

meshing is more an art than a science ;)
Difficult to say without some examples to talk about something specific. That error means basically that one of the edges cannot be subdivided correctly to get a homogeneous mesh on a given face. Often the edge and or face is stated, and then you can Zoom in with the Zoom icon (+ some fiddling in the mesh view selection edge, face, volume ...) to try to understand the issue, but often it's far from obvious.

Partitioning is the best way, still each case is asking for a different approach, see the excellent blog:

www.comsol.eu/blogs/improving-your-meshing-with-partitioning/

and the other mesh related blogs

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Good luck
Ivar

Julien,

I attached my model without any mesh or solutions. If there is a better way to upload my mesh, please let me know the method details.

If you build the mesh in my model as is, you should get the error I am talking about (it may take many minutes). The error seems to be associated with the faces or edges that I placed mapped mesh on. Each time I tried to mesh the model, the error was in a different location (but I only did it 3 times).

I will read up on using partitions to see if that can resolve the issue, but if you have any other recommendation, I would appreciate the help. Note, I am solving the eigenfunction around 7 GHz, so I need my mesh to be no larger than 0.35 inches (lambda/5) and I need include the small gaps at the top and bottom, as they cause a capacitance effect I need to capture. This is why the model has a lot of detail and the mesh is so refined.

Thank you,
Ian

Hi

You have a nice model of an true engineering object that requires defeaturing before meshing.
You will probably manage to mesh it if you use better the symmetries and make more "unions" particularly for en two end pieces.

A few tricks as you have a lot of symmetry, try to use these for the geometry generation it will help for the meshing strategy you can use copy and mirror ...

Then you have a long cylindrical section in the middle (probably better meshed with a structured mesh rather than free Tet's, try to cut through (partition) all your volumes such that the end parts are meshed separately (do add several mesh sub nodes and mesh from one end and mesh

And I suspect you need to add the vacuum by a fully contained cylinder, perhaps with INF or PML layers the latter need structured mesh for best response
========== correction I missed that you use one View with hidden elements, you know you can have several Views and hide different elements in the different views

Three are many ways to handle such a model, but definitively it's meshable ;)
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Good luck
Ivar

Hi,

You can use free triangular mesh on cross surfaces.
I think that the little holes are the problem. Maybe you can add some new domains closed to these holes, when you achieve to mesh in volume these new domains you can try to mesh the big cylinder.

Julien

Ivan,

I read up on partitions and mesh control operations. I am using version 4.2a. Those options did not appear in COMSOL until 4.3(b). I found this forum topic that discusses partitioning in 4.2, but this partitions the entire model, not just for meshing purposes: www.comsol.com/community/forums/geometry/thread/19901/. Would this still be useful in resolving my meshing and would I pay a cost in my solver?

I am able to mesh the model, but it requires 300K elements. I want to get that below 100K to reduce solver time. I am not sure I understand how copying geometry helps with meshing. Does COMSOL note geometry copying/mirroring and do the same with the mesh automatically, or will I need to instruct it to do so?

Thank you very much for all your help,
Ian