fem analisys on carbon tube frame gmesh warnings...

About the development of the FEM module/workbench.

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josheeg
Posts: 82
Joined: Tue Nov 12, 2013 3:10 pm

fem analisys on carbon tube frame gmesh warnings...

Postby josheeg » Sat Jul 21, 2018 3:33 pm

I am running windows 10 freecad .17 13522 git
I assembled some parts the dragonplate carbon fiber pieces I modeled using assembly2.
Now I get a error when I gmesh it.
The other generator works but the solver does not it says 0.0: Check dependencies...
I am using tubes maby that shape is not good for this? :mrgreen: :geek: :ugeek:
fem2.png
fem2.png (212.51 KiB) Viewed 496 times
fem.png
fem.png (205.27 KiB) Viewed 496 times
0.0: We are going to start ...
0.0: Start Gmsh ...
3.7: Gmsh had warnings ...
3.7: Warning : OCC Project Point on Surface FAIL Warning : OCC Project Point on Surface FAIL Warning : OCC Project Point on Surface FAIL Warning : OCC Project Point on Surface FAIL Warning : OCC Project Point on Surface FAIL Warning : OCC Project Point on Surface FAIL Warning : OCC Project Point on Surface FAIL Warning : OCC Project Point on Surface FAIL Warning : OCC Project Point on Surface FAIL Warning : OCC Project Point on Surface FAIL Warning : OCC Project Point on Surface FAIL Warning : OCC Project Point on Surface FAIL Warning : OCC Project Point on Surface FAIL Warning : OCC Project Point on Surface FAIL Warning : OCC Project Point on Surface FAIL Warning : OCC Project Point on Surface FAIL Warning : OCC Project Point on Surface FAIL Warning : OCC Project Point on Surface FAIL Warning : OCC Project Point on Surface FAIL Warning : OCC Project Point on Surface FAIL Warning : OCC Project Point on Surface FAIL Warning : OCC Project Point on Surface FAIL Warning : OCC Project Point on Surface FAIL Warning : OCC Project Point on Surface FAIL Warning : OCC Project Point on Surface FAIL Warning : OCC Project Point on Surface FAIL Warning : OCC Project Point on Surface FAIL Warning : OCC Project Point on Surface FAIL Warning : OCC Project Point on Surface FAIL Warning : OCC Project Point on Surface FAIL Warning : OCC Project Point on Surface FAIL Warning : OCC Project Point on Surface FAIL Warning : OCC Project Point on Surface FAIL Warning : OCC Project Point on Surface FAIL Warning : OCC Project Point on Surface FAIL Warning : OCC Project Point on Surface FAIL Warning : OCC Project Point on Surface FAIL Warning : OCC Project Point on Surface FAIL Warning : OCC Project Point on Surface FAIL Warning : OCC Project Point on Surface FAIL Warning : OCC Project Point on Surface FAIL Warning : OCC Project Point on Surface FAIL Warning : OCC Project Point on Surface FAIL Warning : OCC Project Point on Surface FAIL Warning : OCC Project Point on Surface FAIL Warning : OCC Project Point on Surface FAIL Warning : OCC Project Point on Surface FAIL Warning : OCC Project Point on Surface FAIL Warning : Surface mesh: worst distortion = -6.45584 (avg = 0.496641, 418 elements with jac.
3.7: Gmsh done!
thschrader
Posts: 1757
Joined: Sat May 20, 2017 12:06 pm
Location: Germany

Re: fem analisys on carbon tube frame gmesh warnings...

Postby thschrader » Sat Jul 21, 2018 8:57 pm

Try to use 2D-shell elements.
The "pipe" you see has a diameter of 10 mm and a length of 1000 mm.
In FEM, you can define a shell thickness. No need to use 3D-meshing.
2D_shell_elements.JPG
2D_shell_elements.JPG (96.5 KiB) Viewed 478 times
josheeg
Posts: 82
Joined: Tue Nov 12, 2013 3:10 pm

Re: fem analisys on carbon tube frame gmesh warnings...

Postby josheeg » Sun Jul 22, 2018 5:20 am

I got errors again. I did not go that far I made a cube chamfered and the other one like that some edges. Gmeshed it and got errors. A normal cube no error Because I was surprised then and wondered if I had something installed wrong but it is just win 10 and the latest stable freecad release. ???
thschrader
Posts: 1757
Joined: Sat May 20, 2017 12:06 pm
Location: Germany

Re: fem analisys on carbon tube frame gmesh warnings...

Postby thschrader » Sun Jul 22, 2018 9:30 am

josheeg wrote:
Sun Jul 22, 2018 5:20 am
I got errors again. I did not go that far I made a cube chamfered and the other one like that some edges. Gmeshed it and got errors. A normal cube no error Because I was surprised then and wondered if I had something installed wrong but it is just win 10 and the latest stable freecad release. ???
Can you post your FC-file with your model?
To reduce file-size: in model-tree, right click on FEM-mesh, then "clear mesh"
josheeg
Posts: 82
Joined: Tue Nov 12, 2013 3:10 pm

Re: fem analisys on carbon tube frame gmesh warnings...

Postby josheeg » Sun Jul 22, 2018 1:58 pm

I got a solver to work! :D I tried re-running the examples they ran. I tried asking myself what is different.
Material I was selecting aluminum... in examples I seen calculix steel and wood for the fem popsicle stick bridge example.
If you select aluminum it stops at check references...
I made a simple half frame out of a block sketch extruded .5"
The shell tool in parts workbench did not seem to work.
The fem shell tool looks like it is for faces but realy I would want a hollow of my 3d model?
Well I am glad to see the simulation run now I wonder if I can make the dragon plate carbon fiber tube material.
:mrgreen: :geek: :ugeek:
strength.png
strength.png (226.38 KiB) Viewed 430 times
josheeg
Posts: 82
Joined: Tue Nov 12, 2013 3:10 pm

Re: fem analisys on carbon tube frame gmesh warnings...

Postby josheeg » Sun Jul 22, 2018 2:00 pm

here is all of them but one.
Attachments
skeleton frame.FCStd
(207.53 KiB) Downloaded 9 times
pcft_5_4_98_in.FCStd
(10.82 KiB) Downloaded 10 times
pcft_5_4_72_in.FCStd
(10.81 KiB) Downloaded 11 times
pcft_5_4_48_in.FCStd
(10.77 KiB) Downloaded 10 times
pcft__5_4_24_in.FCStd
(10.83 KiB) Downloaded 11 times
josheeg
Posts: 82
Joined: Tue Nov 12, 2013 3:10 pm

Re: fem analisys on carbon tube frame gmesh warnings...

Postby josheeg » Sun Jul 22, 2018 2:01 pm

oh 2 here are all of them.
Attachments
threaded_tube_connector.FCStd
(14.78 KiB) Downloaded 9 times
cube_v_threaded_1_in.FCStd
(38.3 KiB) Downloaded 10 times
josheeg
Posts: 82
Joined: Tue Nov 12, 2013 3:10 pm

Re: fem analisys on carbon tube frame gmesh warnings...

Postby josheeg » Sun Jul 22, 2018 2:18 pm

gmesh does not seem to close and it throws a error when trying to run the solver volume in geometry like error.
thschrader
Posts: 1757
Joined: Sat May 20, 2017 12:06 pm
Location: Germany

Re: fem analisys on carbon tube frame gmesh warnings...

Postby thschrader » Sun Jul 22, 2018 4:58 pm

josheeg wrote:
Sun Jul 22, 2018 2:18 pm
gmesh does not seem to close and it throws a error when trying to run the solver volume in geometry like error.
Hi josheeg,
I had a look at your files.
The easiest way is to calculate the tubes "by hand" and use FEM only
for the connection-cubes.
Rerun FEM:
Load my FC-file.
In model-tree: doubleclick an analysis activates FEM-wb
doubleclick on mesh (model-tree) open mesh-dialog, remesh.
run solver.
For me alu works.
cube_v_threaded_FEM.FCStd
(42.79 KiB) Downloaded 11 times
cube.JPG
cube.JPG (66.14 KiB) Viewed 412 times
josheeg
Posts: 82
Joined: Tue Nov 12, 2013 3:10 pm

Re: fem analisys on carbon tube frame gmesh warnings...

Postby josheeg » Sun Jul 22, 2018 5:06 pm

Why would I not assemble them can I just model them all as carbon and watch what changes color and deforms I don't know how to hand calculate the tubes.