Help with solvers

About the development of the FEM module/workbench.

Moderator: bernd

I_failed_Cpp
Posts: 1
Joined: Fri Sep 06, 2019 8:59 pm

Help with solvers

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
User avatar
bernd
Posts: 9003
Joined: Sun Sep 08, 2013 8:07 pm
Location: Zürich, Switzerland

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
User avatar
bernd
Posts: 9003
Joined: Sun Sep 08, 2013 8:07 pm
Location: Zürich, Switzerland

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.
User avatar
saso
Posts: 1387
Joined: Fri May 16, 2014 1:14 pm
Contact:

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.