Integrating Elmer into FreeCAD FEM workbench

General discussion about Elmer

Re: Integrating Elmer into FreeCAD FEM workbench

Postby mzenker » 23 Aug 2016, 12:49

Hi Vejmarie,

I have just installed FreeCAD and started to play around with it, trying to generate two adjacent cubes and mesh them. Knowing how to do this with Salomé, I would need to make a partition first in order to get a matching mesh at the interface. How do I do this in FreeCAD? Should I better ask that kind of questions at the FreeCAD forum?
Second question: What do I have to install in order to see the Elmer module (or what already exists of it)? I have installed the stable Win64 version.

Thanks for a hint,

Matthias
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Re: Integrating Elmer into FreeCAD FEM workbench

Postby mzenker » 23 Aug 2016, 13:41

Next question:
according to the documentation, a mesh cannot currently be exported in unv format. But that one would be needed for Elmer. Is it planned to implement unv (as in Salomé)?

Matthias
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Re: Integrating Elmer into FreeCAD FEM workbench

Postby Wil » 28 Nov 2016, 12:39

Concerning your question regarding .unv export, you simply mark the part you want to export and choose File->Export-> Choose .unv .
The exported files can than be easily translated with ElmerGrid.
You can already define some boundary groups by simply applying constraints (e.g. fixed boundary) and exporting the mesh. It does not matter which type of constraint you use in Freecad, it is just for grouping the boundaries.

BR,
Wil
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Re: Integrating Elmer into FreeCAD FEM workbench

Postby mzenker » 28 Nov 2016, 12:44

Hi,

thank you for your answer.
However, I would need to mesh mutlibody geometries in order to be able to use the FreeCAD mesh module for my simulations.

Thanks,

Matthias
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Re: Integrating Elmer into FreeCAD FEM workbench

Postby tmd63 » 02 Dec 2016, 13:34

Hi,
How did the Elmer module work with FreeCAD. Were the tests successful?
I am interested in how this works. I need to simulate shock and vibration on a PCB assembly and could output an STP file that may be loaded into FreeCAD. But as I am new to Elmer and the whole Vibration Analysis, I would be interested in how you efforts were going.
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Re: Integrating Elmer into FreeCAD FEM workbench

Postby mzenker » 02 Dec 2016, 13:43

Hi,

I wasn't able to test it yet.
In the meantime, I advise to use the Salomé mesher.

HTH,

Matthias
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Re: Integrating Elmer into FreeCAD FEM workbench

Postby Wil » 07 Dec 2016, 17:11

mzenker wrote:However, I would need to mesh mutlibody geometries in order to be able to use the FreeCAD mesh module for my simulations.

It is now possible to define multibody geometries/meshes in Freecad. Please see here for some basic examples http://forum.freecadweb.org/viewtopic.p ... 05#p147949 .

tmd63 wrote:How did the Elmer module work with FreeCAD. Were the tests successful?
I am interested in how this works.

There is no Elmer Integration done yet. Before starting the integration the multibody-meshing has to be polished a little bit further. Therefore, testers are welcome to give feedback. You also can use FC to simply create your complete mesh including boundary and domain definition for ElmerGUI 'without' the need of Gmsh and Salome.
BR,
Wil
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Re: Integrating Elmer into FreeCAD FEM workbench

Postby RaJa » 08 Dec 2016, 11:28

This looks quite promising!! Is there a tutorial on how to achieve the multi-body mesh?

Is there another tutorial about how to add functionality to FreeCAD via Python scripts? Interesting part is, how the external Python script (link to ELMER) can be integrated in the GUI.
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Re: Integrating Elmer into FreeCAD FEM workbench

Postby Wil » 09 Dec 2016, 16:08

RaJa wrote:This looks quite promising!! Is there a tutorial on how to achieve the multi-body mesh?

No there is no specific tutorial for creating a multi-body mesh. Please see the tutorials for the FEM-Workbench in the wiki (http://freecadweb.org/wiki/index.php?ti ... tilever_3D, http://freecadweb.org/wiki/index.php?title=FEM_Module) to learn how it is intended to work with FEM-WB.
EDIT: This is needed to see/find the used Constraint-elements/definitions from the current in FC used solver 'calculix'. These definitions are used for setting boundary-constraints (they are also exported with their FC-name to .unv.) while material definitions are used to create different domain/body. The mesh can be tuned by using mesh-regions (which are not in master now but you can use the femmeshregion branch of bernd to test it, see below).

Then you can follow the discussion over here .... http://forum.freecadweb.org/viewtopic.php?f=18&t=18780 and study the added pictures and look into the files (with an updated Freecad from https://github.com/berndhahnebach/FreeC ... meshregion).

RaJa wrote:Is there another tutorial about how to add functionality to FreeCAD via Python scripts? Interesting part is, how the external Python script (link to ELMER) can be integrated in the GUI.

I think this is what you are looking for.... http://forum.freecadweb.org/viewtopic.php?f=22&t=4887
... it is a post from bernd who is also coding the multibody-mesh in FC.
There is also the idea to reuse some python-code written for the integration of Elmer into Salome ... see this discussion viewtopic.php?f=15&t=3636&start=0 (This is more or less for documentation ... Rainer, you know this post)

BR,
Wil
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Re: Integrating Elmer into FreeCAD FEM workbench

Postby tmd63 » 09 Dec 2016, 18:55

In the meantime, I advise to use the Salomé mesher.

I had a look at Salome. I am on a windows 7 system. I noticed there are only linux/unix installs listed. So maybe it is not so easy to get Salome to work for me.
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