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Is it possible to do FEM using hexahedral elements in Mathematica? If it possible, is there any help to do that?

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I think it is not possible in reasonable time. –  andre Apr 11 '13 at 15:33
    
To complicated, no advanced feature for FEM in the kernel yet, NDSolve doesn't use FEM methods –  andre Apr 11 '13 at 17:33
    
are you asking about meshing or about solving ? –  george2079 Apr 11 '13 at 18:41
    
@george2079 about solving. can you help me? –  user6527 Apr 12 '13 at 6:31
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The free Imtek Mathematica Supplement IMS ( https://simulation.uni-freiburg.de/downloads/ims ) does include hexaedron elements for FEM. As far as I know it has Not been updated in several years, therefore I do not expect all of it to work in Mathematica version 8 or 9. Here is an example of a calculation with tetrahedral elements ( http://homepage.cem.itesm.mx/jose.luis.gomez/research/fem2/index.html ). As you can see in that example, IMS does not use Mathematica for meshing, but other external meshing programs. Therefore, eventhough the hexaedron element does exist in IMS, you further need to create the mesh either with another program or to implement that yourself in Mathematica. If you install IMS in your computer, you will find the IMS documentation in the "Installed add-ons" section of Mathematica's documentation center. Then, the documentation about the hexaedral element can be found in ComputationalGeometry->Graphs->MeshElementLibrary, at the bottom of the page. If you decided to use IMS, I suggest you review carefully the application examples of FEM named "Quick Example(Mixed Elements 2D)" and "Quick Example(Periodic Boundaries 2D)", also in IMS documentation

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nice to hear from you! It's tlyru the IMS has not been updated in some years (would that be of interest?) but it still works OK. –  user21 Apr 12 '13 at 5:55
    
Hello Oliver! Yes I know IMS does work in version 8 and 9, I have use it in small, introductory lectures to FEM, however I thought I should warn a new user, specially since the documentation of IMS does include some non-IMS legacy/obsolete Mathematica commands. I do have some ideas about a possible updating of IMS: 1)To incorporate (at least some more) meshing inside Mathematica 2)Maybe to replace imsNexus with GraphicsComplex, or to integrate them somehow 3)To build higher-level commands, folloing the automation philosophy of Mathematica (aiming to a NDSolve-like command) –  MaTECmatica Apr 12 '13 at 13:33
    
Here is the link to the document I use to give an introduction to FEM (in Spanish). IMS is used after page 25, before that standard Mathematica is used to introduce some basic FEM concepts homepage.cem.itesm.mx/jose.luis.gomez/data/mathematica/… –  MaTECmatica Apr 12 '13 at 13:36
    
that pde quite nice! And yes, it's quite correct that there are some issues with IMS when used in newer versions of M-. What do you have in mind for meshing, what would be useful? –  user21 Apr 12 '13 at 14:48
    
Regarding meshing, most of IMS was developed before Mathematica version 6. At that time the graphics in Mathematica were very different. Now, with the use of GraphicsComplex and meshing functions, you can generate I plot like this RegionPlot[-1 <= x <= 1 && -0.5 <= y <= 0.5 && (x - 0.4)^2 + y^2 >= 0.1, {x, -1, 1}, {y, -1, 1}, Mesh -> All] which looks just like an example for a FEM meshing program, I know that mesh was designed for visualization, but some IMS commands could be designed to use that mesh and get some results, going in the direction of the NDSolve-like automation –  MaTECmatica Apr 12 '13 at 17:43
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