[Gmsh] Meshing stackup with thin & thick layers

Tue Oct 7 14:42:37 CEST 2014

If one layer of tetrahedra in the thin layer is OK for you, you can set the characteristic lengths at the corners, try different algorthms (Delaunay, tetgen) and see if you get the mesh you want that way. If you really need anisotropic mesh width, then it depends on the actual state of the MMG3D algorithm, which I don’t know…

Matthias

Von: Drew D [mailto:drewd423 at gmail.com]
Gesendet: Dienstag, 7. Oktober 2014 14:37
An: Zenker, Dr. Matthias
Cc: Christophe Geuzaine; gmsh at geuz.org
Betreff: Re: [Gmsh] Meshing stackup with thin & thick layers

Thanks for the response, Dr. Zenker. So it doesn't sound like there is a good way to do what I want currently?

Drew

On Tue, Oct 7, 2014 at 4:14 AM, Zenker, Dr. Matthias <Matthias.Zenker at erbe-med.com<mailto:Matthias.Zenker at erbe-med.com>> wrote:
Hi,

AFAIK in Elmer you cannot assign a material to a surface in a 3D simulation, so you need those very flat volumes.
There is a 3D meshing algorithm in gmsh (MMG3D) which in principle allows anisotropic mesh width. I have not succeeded in the past to get it working for a similar problem, as it was not available for volumes with internal boundaries. See the following post from the mailing list: http://www.geuz.org/pipermail/gmsh/2013/008379.html. This is a year ago, however, and things might have evolved since then.

@Christophe: Have they…? ;)

HTH,

Matthias

Von: Drew D [mailto:drewd423 at gmail.com<mailto:drewd423 at gmail.com>]
Gesendet: Montag, 6. Oktober 2014 14:52
An: Christophe Geuzaine
Cc: gmsh at geuz.org<mailto:gmsh at geuz.org>
Betreff: Re: [Gmsh] Meshing stackup with thin & thick layers

Christophe,

Thanks for the response. Don't I need to treat them as volumes so that I can assign them different materials in my solver? I'm using Elmer, btw.

Drew

On Mon, Oct 6, 2014 at 4:16 AM, Christophe Geuzaine <cgeuzaine at ulg.ac.be<mailto:cgeuzaine at ulg.ac.be>> wrote:

On 01 Oct 2014, at 22:23, Drew D <drewd423 at gmail.com<mailto:drewd423 at gmail.com>> wrote:

> I have a composite stackup with alternating thin & thick layers. The thick ones are are rougly 10x the thickness of the thin ones, and the aspect ratio is on the order of 100:1. The mesh for something like this is always huge. Is there a way to treat the thin layers as 2D shells, while keeping the thicker ones 3D? The model is being exported as a STEP file and brought into Gmsh.
>

Just include the surfaces in your model; Gmsh generates conformal meshes so this internal surface can then be treated as a thin layer in your solver. If you need duplicated nodes on the surface (which Gmsh normally does not generate), you can run Plugin(Crack) on the resulting mesh.

> Thanks,
> Drew
> _______________________________________________
> gmsh mailing list
> gmsh at geuz.org<mailto:gmsh at geuz.org>
> http://www.geuz.org/mailman/listinfo/gmsh

--
Prof. Christophe Geuzaine
University of Liege, Electrical Engineering and Computer Science
http://www.montefiore.ulg.ac.be/~geuzaine

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