Felt in FEM Workbench

About the development of the FEM module/workbench.

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Sudhanshu
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Felt in FEM Workbench

Postby Sudhanshu » Tue Jan 15, 2019 4:46 am

Kunda1 wrote:
Mon Jan 14, 2019 11:48 am
Sudhanshu wrote:
Mon Jan 14, 2019 10:42 am
I wish to work on adding FElt as a solver in the FEM workbench.
For that purpose I have tried to understand how other solvers take input and show output in FreeCAD from the source code but that wasn't
much helpful.
So a pointer in the right direction would be really helpful.
Try following this thread on ooFem whereby @bernd mentors how to integrate a solver in to FEM. Also you probably want to start your own thread and perhaps reference it from this thread so people can follow it (to avoid hijacking this thread)
Thanks!
I will go through that thread and see what all I could learn from it.
Sudhanshu
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Re: Felt in FEM Workbench

Postby Sudhanshu » Tue Jan 15, 2019 5:22 am

bernd wrote:
Mon Jan 14, 2019 11:54 am
Sudhanshu wrote:
Mon Jan 14, 2019 10:42 am

I wish to work on adding FElt as a solver in the FEM workbench.
For that purpose I have tried to understand how other solvers take input and show output in FreeCAD from the source code but that wasn't
much helpful.
So a pointer in the right direction would be really helpful.


last version on sourceforge is from 2009 and last windows version is from 2000 :shock: Only the non officeal github repo has activity. Which seams your repo! Has the project been reactivated on github?
The original developers left the Felt project after releasing from 3.02 to 3.05 (as per the Changelog), and they had the copyright till 2005 (as per the User Guide).
A developer pvossos picked up the Felt code in 2000 and started working on it. He has releases till 3.07 (same as on sourceforge) and his last commit was from 2011. He also had a branch in which he was preparing for the 3.08 release but had to stop his work due to personal reasons.

What I worked on was a fork of pvossos repo by inderpreetsingh. When I picked up felt, it had errors in it because of the changes in C++ that had happened over time. I removed all the errors (took me a considerable time) and had to remove Burlap (an octave-like mathematical environment for felt) and Velvet (a GUI for felt) so that felt could compile on the latest linux system with latest c++.

So yeah, felt has been revived but I can't develop it further for a 3.08 release due my lack of knowledge of FEM.
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bernd
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Re: Felt in FEM Workbench

Postby bernd » Tue Jan 15, 2019 6:23 am

check this branch https://github.com/berndhahnebach/FreeC ... s/femoofem I rewrote history for a better understanding what is needed for a new solver ...

bernd

ahh welcome to the world of FreeCAD FEM ... :D
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bernd
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Re: Felt in FEM Workbench

Postby bernd » Tue Jan 15, 2019 6:39 am

what is the advantage of felt compared to other FEM solver like CalculiX, Elmer and OOFEM ?

bernd
Sudhanshu
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Re: Felt in FEM Workbench

Postby Sudhanshu » Tue Jan 15, 2019 9:19 am

bernd wrote:
Tue Jan 15, 2019 6:39 am
what is the advantage of felt compared to other FEM solver like CalculiX, Elmer and OOFEM ?

bernd
Correct me if I am wrong but as far as I know all the other solvers have 3D solid elements and don't support 1D beam element.
Felt has 1D beam element which is used to solve frames, i.e beams and columns and their assembly.

Thus, having Felt in FreeCAD will help in efficient and economical solving of beam elements.
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bernd
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Re: Felt in FEM Workbench

Postby bernd » Tue Jan 15, 2019 11:57 am

Sudhanshu wrote:
Tue Jan 15, 2019 9:19 am
bernd wrote:
Tue Jan 15, 2019 6:39 am
what is the advantage of felt compared to other FEM solver like CalculiX, Elmer and OOFEM ?

bernd
Correct me if I am wrong but as far as I know all the other solvers have 3D solid elements and don't support 1D beam element.
Felt has 1D beam element which is used to solve frames, i.e beams and columns and their assembly.

Thus, having Felt in FreeCAD will help in efficient and economical solving of beam elements.
That is true. Neither CalculiX nor Z88 have native beam elements. I do not know about Elmer.

XCFEM ( https://forum.freecadweb.org/viewtopic.php?f=18&t=31262 ) has beam elements. Thus I am experimenting with this solver.

OOFEM the one harry has started to implement does beam elements as well (http://www.oofem.org/resources/doc/elem ... alsu2.html) AFAIK, and is still in development! Furthermore it can some nice stuff in the regard of nonlinear material needed for concrete ...

BTW: What mesh format does Felt uses for input and what format does use Felt for results? Any standard format?
Sudhanshu
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Re: Felt in FEM Workbench

Postby Sudhanshu » Sat Jan 19, 2019 5:35 am

bernd wrote:
Tue Jan 15, 2019 11:57 am

BTW: What mesh format does Felt uses for input and what format does use Felt for results? Any standard format?
In Felt, corduroy is the application used for meshing. From felt.pdf (User's Guide and Reference Manual):

<q>

corduroy is a command line application for
automatically generating nodes and elements. It takes
a text input file and generates FElt format nodes and
elements for inclusion into a FElt problem. Like felt
then, it is a command line interface to some of the
same functionality that you can get in velvet.
However, unlike felt and velvet, which share their
file syntax (the standard FElt syntax), corduroy has
its own special syntax to describe the way elements
are generated.

</q>

For results, Felt uses a text file.
And I don't think it uses any standard format for either input or output.
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bernd
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Re: Felt in FEM Workbench

Postby bernd » Sat Jan 19, 2019 6:16 am

a cool, but it seams you could use some other mesher too. This would you get started faster ...
Sudhanshu
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Re: Felt in FEM Workbench

Postby Sudhanshu » Mon Jan 21, 2019 2:59 am

bernd wrote:
Sat Jan 19, 2019 6:16 am
a cool, but it seams you could use some other mesher too. This would you get started faster ...
What are the other meshers that are already there in FreeCAD?
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bernd
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Re: Felt in FEM Workbench

Postby bernd » Mon Jan 21, 2019 9:25 pm

Netgen and Gmsh, try them in FEM WB.