Questions concerning the INP file format

About the development of the FEM module/workbench.

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uwestoehr
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Questions concerning the INP file format

Postby uwestoehr » Sun Mar 10, 2019 3:16 pm

In the FC preferences, section Import-Export -> INP there are 2 options that I don't understand:

- Which mesh elements to export
The tooltip states that "If Highest is selected, only the highest elements will be exported." but what is meant with "highest elements". Are there several elements the highest ones?

- Export group data
There is no tooltip and I couldn't google what this option means.

(These are the 2 open points in https://www.freecadweb.org/wiki/Preferences_Editor#INP )
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bernd
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Re: Questions concerning the INP file format

Postby bernd » Mon Mar 11, 2019 3:16 pm

uwestoehr wrote:
Sun Mar 10, 2019 3:16 pm
In the FC preferences, section Import-Export -> INP there are 2 options that I don't understand:
- Export group data
There is no tooltip and I couldn't google what this option means.
select a mesh and show in poperty editor Data there is the mesh informations. If there are groups and the pref is set to export them, they are exported. Attached a rather small mesh with 10 groups. Export to *.inp and have a look at the inp files in an editor.


mesh_with_groups.FCStd
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bernd
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Re: Questions concerning the INP file format

Postby bernd » Mon Mar 11, 2019 3:43 pm

uwestoehr wrote:
Sun Mar 10, 2019 3:16 pm
In the FC preferences, section Import-Export -> INP there are 2 options that I don't understand:

- Which mesh elements to export
The tooltip states that "If Highest is selected, only the highest elements will be exported." but what is meant with "highest elements". Are there several elements the highest ones?
https://github.com/FreeCAD/FreeCAD/blob ... 1296-L1305

the standard mesh process for a solid mesh is as follows:

- mesh the edges, save these elements
- mesh the shell, save these elements
- mehs the solid, save these elements

means a solid mesh has edge, shell and volume elements. Select the mesh from 3D FEM cantilever example, right click mesh informations.

For the analysis of a solid mesh only the solid mesh elements are needed. All would export Edge, Shell and Volume elements. Highest would only export the highest order, means Volumes for a Volume mesh and Faces for a Shell mesh. FEM was implemented for mixed meshes it export the following elements: only edges not belonging to faces and faces not belonging to volumes

See https://github.com/FreeCAD/FreeCAD/blob ... 1296-L1305

BUT the FEM is nearly useless ... :oops: It is easy possible to have an mixed mesh in which a edge which belongs to a face is needed for an edge too. A simple example is a slab the a beam or pretension. The slab is modelled with a shell elements and the beam (pre tension) with edge elements. These edges belong to the face of the slab.

Any way the FEM was really helpful when I started to implement the mixed mesh analyis, which is not finished because of the described export problem.

Bernd
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bernd
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Re: Questions concerning the INP file format

Postby bernd » Mon Mar 11, 2019 3:52 pm

bernd wrote:
Mon Mar 11, 2019 3:43 pm

BUT the FEM is nearly useless ... :oops: It is easy possible to have an mixed mesh in which a edge which belongs to a face is needed for an edge too. A simple example is a slab the a beam or pretension. The slab is modelled with a shell elements and the beam (pre tension) with edge elements. These edges belong to the face of the slab.

Any way the FEM was really helpful when I started to implement the mixed mesh analyis, which is not finished because of the described export problem.
We might should rename or deactivate the option?
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uwestoehr
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Re: Questions concerning the INP file format

Postby uwestoehr » Mon Mar 11, 2019 11:07 pm

bernd wrote:
Mon Mar 11, 2019 3:16 pm
select a mesh and show in poperty editor Data there is the mesh informations. If there are groups and the pref is set to export them, they are exported. Attached a rather small mesh with 10 groups. Export to *.inp and have a look at the inp files in an editor.
Thank you. This is now described.

While playing around with the latest FC Conda build I got this error when applying a material:

Code: Select all

Traceback (most recent call last):
  File "C:\FreeCAD\FreeCAD_0.18.16078_Conda_Py3QT5-WinVS2015_x64\Mod\Fem\femguiobjects\_ViewProviderFemMaterial.py", line 219, in choose_material
    self.set_mat_params_in_input_fields(self.material)
  File "C:\FreeCAD\FreeCAD_0.18.16078_Conda_Py3QT5-WinVS2015_x64\Mod\Fem\femguiobjects\_ViewProviderFemMaterial.py", line 509, in set_mat_params_in_input_fields
    self.parameterWidget.spinBox_poisson_ratio.setValue(float(matmap['PoissonRatio']))
Maybe this is relevant?

OS: Windows 7
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.18.16078 (Git)
Build type: Release
Branch: master
Hash: 67df9f3a828fbb0fec29d039792d4baf3d9ee8e0
Python version: 3.6.6
Qt version: 5.6.2
Coin version: 4.0.0a
OCC version: 7.3.0
Locale: German/Germany (de_DE)
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uwestoehr
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Re: Questions concerning the INP file format

Postby uwestoehr » Mon Mar 11, 2019 11:20 pm

uwestoehr wrote:
Mon Mar 11, 2019 11:07 pm
While playing around with the latest FC Conda build I got this error when applying a material:
This is now a separate bug report:
https://forum.freecadweb.org/viewtopic.php?f=38&t=34847
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uwestoehr
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Re: Questions concerning the INP file format

Postby uwestoehr » Mon Mar 11, 2019 11:27 pm

bernd wrote:
Mon Mar 11, 2019 3:52 pm
We might should rename or deactivate the option?
If the option doesn't really change anything, the option should be removed, otherwise be renamed.
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bernd
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Re: Questions concerning the INP file format

Postby bernd » Tue Mar 12, 2019 9:29 am

uwestoehr wrote:
Mon Mar 11, 2019 11:27 pm
bernd wrote:
Mon Mar 11, 2019 3:52 pm
We might should rename or deactivate the option?
If the option doesn't really change anything, the option should be removed, otherwise be renamed.
It is not that the options does not change anything. It is just it is not as useful as asumed when it was implemented. Furthermore the name FEM ist not a good name. I will think of something better in 0.19. Feel free to make a FEM bug report and assign it to me.