fem analisys on carbon tube frame gmesh warnings...

About the development of the FEM module/workbench.

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

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

Postby josheeg » Sun Jul 22, 2018 5:19 pm

Here is what I have as aluminum in the picture it is a windows 10 newest freecad no other programs.
femalu.png
femalu.png (250.65 KiB) Viewed 255 times
The connector for the tubes that has the exact OD as the tubes ID so I wonder if the material choice and the assembly didnt properly manafold like I expected. In other words maby if I want to assemble something make the bolts bigger than the holes so the boolian merge in assembly2 or part workbench can make them manafold to do fem on them?
femtube.png
femtube.png (242.76 KiB) Viewed 255 times
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bernd
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Re: fem analisys on carbon tube frame gmesh warnings...

Postby bernd » Sun Jul 22, 2018 6:41 pm

WOuld you post your FreeCAD info, it seams you run 0.17 stable ... The aluminium got an fix in 0.18 ... git commit 0c6ed4
josheeg
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Joined: Tue Nov 12, 2013 3:10 pm

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

Postby josheeg » Sun Jul 22, 2018 10:19 pm

I will soon thanks it's great to know those are working. And thanks for showing how it was fixed in git I like how it version controls.

Can things be assembled and fem Ed?

Is it a mux in fem I should use and should things be bigger than the hole so the meshes overlap to make it boolian join and weld the manafold step file for fem?
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bernd
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Re: fem analisys on carbon tube frame gmesh warnings...

Postby bernd » Mon Jul 23, 2018 3:52 am

depends ... if you would like to use two different materials, no they should not overlap, they should share a face, the connection face. A CompSolid is your friend. Use Part Boolean Fragment to create them. See FEM_Shear_of_a_Composite_Block
josheeg
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Re: fem analisys on carbon tube frame gmesh warnings...

Postby josheeg » Wed Jul 25, 2018 3:05 am

I tried 0.18 that is not a official release and I still got a error in the bottom left corner when I selected it in windows 10. it was aluminum number ...
josheeg
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Re: fem analisys on carbon tube frame gmesh warnings...

Postby josheeg » Fri Jul 27, 2018 5:26 am

So if I want to do a fem analysis on a carbon fiber tube system from dragon plate. I would get the tube properties and assume the aluminum connectors are similar in strength. Then I should boolian join them by making the parts that connect make one side larger. ?

The overlap could even represent the chemical welds.

:)