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Meshing for very thin conductors
Posted Jun 8, 2018, 8:49 a.m. EDT Low-Frequency Electromagnetics, Geometry, Mesh Version 5.3 3 Replies
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I am attempting to mesh a simulation of a very thin conductor (0.1 um) with lateral dimensions in the range of 100's of um (for stationary COMSOL AC/DC magnetic and electric fields simulation).
Whenever I attempt to generate a tetrahedral mesh, I get a "face is much smaller than the specificed minimum element size" warning; but if I manually set the minimum element size to 0.1 um the geometry becomes excessively meshed.
It seems like this issue could be solved by a hexahedral mesh option but I can't seem to find that mesh option in COMSOL 5.3
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Regarding meshing objects with high aspect ratios using swept meshes, see this thread
But depending on the specifics of what you want to model and what you want to get out of the model, there may be better solutions than modeling the thin conductor as a 3D entity. Such capabilities are found e.g. in the AC/DC Module: "Modeling Thin Structures For modeling very thin structures, you can use shell formulations that are available for direct currents, electrostatics, magnetostatics, and induction simulations. Electromagnetic shell modeling makes it possible to replace the thickness of a thin solid in a CAD model with a physical property of a surface resulting in a much more efficient representation."
If you need further assistance, please contact support@comsol.com . Best,
Jeff
-------------------Jeff Hiller
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Unfortunately the technique described in the link on high aspect ratios using swept meshes did not converge
I read the Reference Manual chapter 8 on meshing, but it doesn't actually describe any techniques for such extreme 3D aspect ratios
I considered using electromagnetic shell modelling but this would not provide solutions within the small feature, which I will need for my analysis.
Please let me know if you have any recommendations, or if I can provide my COMSOL file for inspection by one of your experts
Thanks
Evan
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Swept meshing, described in Chapter 8 of the Reference Manual, is capable of producing meshes on geometries with higher aspect ratios than the one you are working with. The convergence problem you mention may come from somewhere else entirely, but my guess would be that it is due to ill conditioning induced by those high aspect ratio elements. Please contact support@comsol.com for a more in-depth discussion of your work, should the problem persist.
Best,
Jeff
-------------------Jeff Hiller