add new function to fem module
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Re: add new function to fem module
The time beeing we have set up a very simple example for eigenvalue analysis for Elmer. For this example we have results from Elmer in FreeCAD and from Elmer in the tutorial to compare with. Would be cool if we could extend this example by a calculix solver ...
- see https://forum.freecadweb.org/viewtopic. ... 40#p488277
- and https://github.com/FreeCAD/FreeCAD/blob ... ic_beam.py
If we would get the same results in Calxulix than in Elmer, I would immediately merge the buckling code.
Neverless the lateral torsional buckling problem would be extremly cool to solve too
- see https://forum.freecadweb.org/viewtopic. ... 40#p488277
- and https://github.com/FreeCAD/FreeCAD/blob ... ic_beam.py
If we would get the same results in Calxulix than in Elmer, I would immediately merge the buckling code.
Neverless the lateral torsional buckling problem would be extremly cool to solve too
Re: add new function to fem module
attached the FreeCAD file which calculates the frequencies ... they match, means only the eigenvalue analysis is missing.
which is close to what Elmer tutorial gives ...
Code: Select all
- 643.49
- 1099.57
- 1580.31
- 1650.34
- 2521.68
Re: add new function to fem module
git commit cf241d0c936c
- start FreeCAD
- switch to FEM
- open examples Gui
- setup Solver --> ccxtools --> elmer tutorial 01
- save and run
- frequencies should match
I am curious if the eigenvalues match too?
- start FreeCAD
- switch to FEM
- open examples Gui
- setup Solver --> ccxtools --> elmer tutorial 01
- save and run
- frequencies should match
I am curious if the eigenvalues match too?
Re: add new function to fem module
Cool, Ill have a look at this tomorrow. Should not be hard at all to check.
Update:
I have been struggling making a hex-mesh in GMSH for a couple of days and finally I think I made it work.
Now the buckling factors, from the manual calculation, calculix, and another FEA program are all within a 5% margin.
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Re: add new function to fem module
wow, would you shsre the the file.
Re: add new function to fem module
The elmer example is a frequency calculation, the only that causes compression loads are the self weight of the element. Which is not included in the FreeCAD example.
Why dont we use Calculix verification examples to validate the results instead? The only problem is that you need to manually read the .inp file to try to replicate it in FreeCAD. http://www.feacluster.com/CalculiX/ccx_ ... ode403.php
Re: add new function to fem module
perfect! very good idea! This one http://www.feacluster.com/CalculiX/ccx_ ... beam8b.inp ? Or are there others?
You can import the inp file. The mesh will be imported and can directlx be used for the analysis. Fem utility in mesh menu can convert the fem mesh to surface freecad mesh. with part you get a part. or make this simple part yourself. make the fixes yourself and you should be done.
You can import the inp file. The mesh will be imported and can directlx be used for the analysis. Fem utility in mesh menu can convert the fem mesh to surface freecad mesh. with part you get a part. or make this simple part yourself. make the fixes yourself and you should be done.
Re: add new function to fem module
Ahh material should be Calculix_Standard or similar. Search for a card with Calculix in the card name. It is available in FreeCAD FEM materials ...
Re: add new function to fem module
Yeah exactly, beam8b example.bernd wrote: ↑Thu Mar 18, 2021 2:54 pm perfect! very good idea! This one http://www.feacluster.com/CalculiX/ccx_ ... beam8b.inp ? Or are there others?
You can import the inp file. The mesh will be imported and can directlx be used for the analysis. Fem utility in mesh menu can convert the fem mesh to surface freecad mesh. with part you get a part. or make this simple part yourself. make the fixes yourself and you should be done.
Didnt know you could import an ".inp" file to get the mesh, nice. I already made an hex-mesh, but this is better.
Below is the result from the reference and my calculation with the exact same mesh.
Beam8b.dat Referencefile:
Code: Select all
B U C K L I N G F A C T O R O U T P U T
MODE NO BUCKLING
FACTOR
1 0.5353338E+02
2 0.1123187E+03
3 0.4425644E+03
4 0.8385897E+03
5 0.1063985E+04
6 0.1751251E+04
7 0.1770198E+04
8 0.2406977E+04
9 0.2597970E+04
10 0.2992558E+04
Code: Select all
B U C K L I N G F A C T O R O U T P U T
MODE NO BUCKLING
FACTOR
1 0.5353773E+02
2 0.1123524E+03
3 0.4429172E+03
4 0.8406785E+03
5 0.1066613E+04
6 0.1760440E+04
7 0.1781060E+04
8 0.2428616E+04
9 0.2625109E+04
10 0.3032522E+04
I need to update Calculix on my ubuntu machine and test again. It´s ancient
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- Skärmavbild 2021-03-18 kl. 16.54.48.png (204.28 KiB) Viewed 2332 times