Help with solvers (Nastran)

About the development of the FEM module/workbench.

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I_failed_Cpp
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Help with solvers (Nastran)

Postby I_failed_Cpp » Tue Sep 10, 2019 5:55 pm

I've read the wiki and it seems to indicate that other solvers can be used other than those that come with FreeCAD but I can't figure out how to do that. I'm trying to get the NASA-JPL NASTRAN to run because I have need to do a DDAM analysis. What would that workflow be like? Any help on this appreciated. Also has anyone here gotten pyNastran to work? Apparently someone ported the nastran code to python but I'm not having success getting it to work but I suspect the python port would be easier to get to work within FreeCAD.

Thanks,
Bill
Last edited by Kunda1 on Fri May 01, 2020 11:25 am, edited 1 time in total.
Reason: Added "(Nastran)" to title thread
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bernd
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Re: Help with solvers

Postby bernd » Tue Sep 10, 2019 6:54 pm

Before a new solver runs with FreeCAD FEM the new solver needs to be implemented in FreeCAD FEM. As an example have a look at the implementation of oofem solver in FreeCAD FEM.

https://github.com/berndhahnebach/FreeC ... s/femoofem
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bernd
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Re: Help with solvers

Postby bernd » Wed Sep 11, 2019 5:58 am

mainly what FreeCAD FEM does:

- writes an solver input file
- executes the solver
- reads the results

The biggest part is the input file. Since every solver has its own input file format this usually needs to be implemented.
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saso
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Re: Help with solvers

Postby saso » Wed Sep 11, 2019 1:11 pm

As I understand https://github.com/SteveDoyle2/pyNastran is only about reading and writing the input and output files for Nastran, so you still need the actual solver. While there seems to be some work going on on the open source code of the Nastran https://github.com/SteveDoyle2/NASTRAN-95 I don't think it is actually working, so at least for now, as I understand, one still needs an commercial Nastran solver for this to work.
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Re: Help with solvers

Postby johnwang » Fri May 01, 2020 11:26 am

saso wrote:
Wed Sep 11, 2019 1:11 pm
As I understand https://github.com/SteveDoyle2/pyNastran is only about reading and writing the input and output files for Nastran, so you still need the actual solver. While there seems to be some work going on on the open source code of the Nastran https://github.com/SteveDoyle2/NASTRAN-95 I don't think it is actually working, so at least for now, as I understand, one still needs an commercial Nastran solver for this to work.
Just saw this. Download the 95 version and tried to compile it. 2 errors now.
nas.jpg
nas.jpg (305.63 KiB) Viewed 926 times
Last edited by johnwang on Fri May 01, 2020 11:46 am, edited 2 times in total.
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Re: Help with solvers (Nastran)

Postby johnwang » Fri May 01, 2020 11:36 am

ln is not a DOS command.

Code: Select all

LN=ln -s

ln -s
What's $^ means in Shell command? How can I do it under DOS? I may not need to make this target under DOS.

Code: Select all

NASINFO: rf/NASINFO
	$(LN) $^ $@
Last edited by johnwang on Fri May 01, 2020 12:14 pm, edited 1 time in total.
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saso
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Re: Help with solvers (Nastran)

Postby saso » Fri May 01, 2020 11:57 am

As for the solver, it might be good to review the different forks if someone has done some more work on it (I haven't looked at it for some time)...
https://github.com/OdonataResearchLLC/N ... rk/members

maybe some interesting work to review further after a quick look at the forks
https://github.com/nasa/NASTRAN-95
--- https://github.com/AeroDME/NASTRAN-95
--- https://github.com/OdonataResearchLLC/NASTRAN-95
--- --- https://github.com/SteveDoyle2/NASTRAN-95
--- https://github.com/Open-Cascade-SAS/NASTRAN-95 <- Open Cascade !?
--- https://github.com/twuerfl/NASTRAN-95
--- --- https://github.com/ldallolio/NASTRAN-95
--- --- --- https://github.com/Atamisk/NASTRAN-95
--- --- --- https://github.com/dad98253/NASTRAN-95

Here one can find also some manuals that might come useful at some point :)
https://github.com/SteveDoyle2/NASTRAN- ... /reference

also the pyNastran documentation https://pynastran-git.readthedocs.io/en/latest/

also https://www.mystran.com/ which was developed independently but in general supports the NASTRAN format (similar to CalculiX for Abaqus)
https://github.com/dr-bill-c/MYSTRAN
--- https://github.com/Open-Cascade-SAS/MYSTRAN
Last edited by saso on Sat May 09, 2020 10:44 am, edited 12 times in total.
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saso
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Re: Help with solvers (Nastran)

Postby saso » Fri May 01, 2020 12:01 pm

johnwang wrote:
Fri May 01, 2020 11:36 am
What's this mean? How can I do it under DOS?
mklink ?

https://www.computerhope.com/unix/uln.htm
https://www.computerhope.com/mklink.htm
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Re: Help with solvers (Nastran)

Postby johnwang » Fri May 01, 2020 12:50 pm

saso wrote:
Fri May 01, 2020 11:57 am
As for the solver, it might be good to review the different forks if someone has done some more work on it (I haven't looked at it for some time)...
Just built a few Targets.

nastplot seems working. Is there any test case to plot? Never used nastran. Have no idea.

These two Targets nasthelp & jobs not built yet. Thought they are just files. Maybe could build under Linux and then copied into DOS.
Last edited by johnwang on Sun Jul 26, 2020 8:40 am, edited 4 times in total.
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Re: Help with solvers (Nastran)

Postby johnwang » Mon Jun 29, 2020 3:57 am

um folder means user manual.
Last edited by johnwang on Fri Jul 03, 2020 4:08 am, edited 3 times in total.