Generate a truss and analysis with frame3DD

[johnwang]

Given Span, Pitch angle and a max member length to generate a truss. A Frame3DD input file is generated at the same time. At the moment, only a point load at a fixed node is applied.

Referenced this post: https://forum.freecadweb.org/viewtopic. ... t=frame3dd

Input:

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Result:

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OS: Windows 10 (10.0)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.18778 (Git)
Build type: Release
Branch: master
Hash: f55cf3ef103532c9718c108bd856a4ef06ad49a5
Python version: 3.6.7
Qt version: 5.12.1
Coin version: 4.0.0a
OCC version: 7.3.0

[bernd]

cool, Would you share the code as well? Do you regularly use Frame3DD? If yes we could add it as a real FEM solver!

[johnwang]

cool, Would you share the code as well? Do you regularly use Frame3DD? If yes we could add it as a real FEM solver!

The answer is no. I haven't use Frame3DD before. Just testing.

[vocx]

cool, Would you share the code as well? Do you regularly use Frame3DD? If yes we could add it as a real FEM solver!

I remember this other thread, 2D structures basic calculations. It never got much attention.

https://anastruct.readthedocs.io/en/lat ... arted.html

anaStruct is a Python implementation of the 2D Finite Element method for structures. It allows you to do structural analysis of frames and frames. It helps you to compute the forces and displacements in the structural elements.

Besides linear calculations, there is also support for non-linear nodes and geometric non linearity.

Also this thread, Solving Beam Bending with SymPy.

Maybe these could be implemented as solvers in FEM?

[johnwang]

PointLoads added at two nodes in program, not interactively yet.

frame3dd.exe saved under freecad/bin folde. The generated frame3dd input case file also saved there.

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[johnwang]

After runing frame3dd, it genearets gmsh pos files which shows the orginal truss and deflection under each load case. This example only defined one load case.
These pos files could be viewed with gmsh.

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[bernd]

Depending what kind of obj this is in gmsh you export the objects from gmsh into unv (mesh) or brep (geometry). Both formats could be opened in FreeCAD. I am curious if this works.

bernd

[johnwang]

Depending what kind of obj this is in gmsh you export the objects from gmsh into unv (mesh) or brep (geometry). Both formats could be opened in FreeCAD. I am curious if this works.

bernd

The POS ASCII file is Gmsh’s old native post-processing format. Maybe I should let Frame3DD output in the current MSH file format. Does FreeCad's FEA can show MSH file directly?

chakkree's code can reads Frame3DD's 3DD file and show the mesh in FreeCAD. It's easy to add to show more variable values.

I am interested if FreeCad's FEA can provide its own post-processing format, so people who write their own FEA solver could output in that format and quickly view their result with FreeCAD.

[bernd]

there is a generic postprocessing format already, vtk. FreeCAD FEM supports this format. If a solver would suport vtk the output is suported by FreeCAD FEM out of the box. Otherwise one would need to write a parser for the output format of the solver. This was done for Calculix and z88 output formats in FreeCAD FEM.


https://github.com/FreeCAD/FreeCAD/blob ... Results.py

https://github.com/FreeCAD/FreeCAD/blob ... Results.py

[johnwang]

Read in result file and draw the mesh and dispalcement with two fem::femmesh objects.

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