Comsol Nanoscale Meshing Problem

[keniwas]

Hi Everyone!

I hope someone here can help me with a meshing problem I am experiencing in comsol. What I have is a model which has large scale differences (Ranging from the mm range to the nm range). It seems that with these differences in scale, the free meshing engine has a hard time meshing the subdomains (in 3D) and always fails with a message akin to

Error: 4029
Failed to insert point.
- x coordinate: 5.04031e-005
- y coordinate: 0.002645
- z coordinate: 2.74364e-007
An empty cavity was generated.

I am wondering if there are any tips you might have on how to resolve this problem. I have already tried the swept meshing, however becuase the topology of the subdomain changes from one face to the opposing face (one face has additional boundaries which exist only on that surface), it fails with an invalid topology message.

I have access to the Altair Hyperworks suite which include hypermesh, and I read (http://cds.comsol.com/access/dl/papers/5376/Buchau_pres.pdf ) that hypermesh has been used to successfully model/mesh systems which can then be imported into comsol. Does anyone have any experience with this process? (Which appears to go via the nastran file format). I have attempted to export some of the example models in the hypermesh tutorials to a nastran file, but upon importing into comsol i get an error saying the nastran file was corrupt.

I would really appreciate any input you have on the matter.

Thanks.

 

[mmwave]

Thank you for reaching out with your meshing problem. It sounds like you are dealing with a complex model with a wide range of scales, which can certainly make meshing challenging. Have you tried adjusting the mesh settings, such as the element size or maximum element size, to see if that helps with the failure message you are receiving? Additionally, you may want to try using adaptive meshing, which can automatically refine the mesh in areas of high detail or change in scale.

As for using HyperMesh to model and mesh your system, I do not have personal experience with this process but I have heard of it being successfully used by others. I would recommend reaching out to Altair's technical support for assistance with exporting a compatible nastran file for import into COMSOL.

I hope this helps and good luck with your meshing efforts! Please let us know if you have any further questions or concerns.

 

[oswaler]

Hello,

Thank you for reaching out for help with your meshing problem in Comsol. It sounds like you are facing a common challenge in multi-scale modeling, where differences in scale can make it difficult for the meshing engine to accurately capture all the features in the model. I have a few suggestions that may help you resolve this issue:

1. Consider using adaptive meshing techniques. Comsol has several adaptive meshing methods that can be used to refine the mesh in areas where there are large scale differences. This can help improve the accuracy and efficiency of your simulations.

2. Try using a structured mesh instead of a free mesh. Structured meshes can be more suitable for models with large scale differences, as they can better capture the geometry and features of the model.

3. Use local mesh controls. You can use local mesh controls to specify different mesh sizes in specific areas of your model. This can help improve the mesh quality in areas with large scale differences.

4. Check your geometry. It's possible that there may be some issues with the geometry of your model that are causing the meshing problem. Make sure all your surfaces are properly defined and that there are no gaps or overlaps in your model.

I am not familiar with using Hyperworks to import meshes into Comsol, but it may be worth trying if you continue to have difficulties with the native meshing capabilities in Comsol.

I hope these suggestions are helpful in resolving your meshing problem. If you continue to have issues, I would recommend reaching out to the Comsol support team for further assistance. Good luck with your simulations!