[solved] tube connection
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[solved] tube connection
Hi,
I must calculate a tube connection (R550x12,5 -- R660x16 Steel S235)
under momentum-loading. Meshing works without error, but I cant write
the case. What I am doing wrong? Can someone have a look at this?
Thanks. Thomas Done with:
OS: Windows 10
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.18.15273 (Git)
Build type: Release
Branch: master
Hash: 4e77cee5ee6efa1b28290c10ccb8b2540b9eecaf
Python version: 2.7.14
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 7.2.0
Locale: German/Germany (de_DE)
I must calculate a tube connection (R550x12,5 -- R660x16 Steel S235)
under momentum-loading. Meshing works without error, but I cant write
the case. What I am doing wrong? Can someone have a look at this?
Thanks. Thomas Done with:
OS: Windows 10
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.18.15273 (Git)
Build type: Release
Branch: master
Hash: 4e77cee5ee6efa1b28290c10ccb8b2540b9eecaf
Python version: 2.7.14
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 7.2.0
Locale: German/Germany (de_DE)
Last edited by thschrader on Fri Nov 30, 2018 2:06 pm, edited 1 time in total.
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Re: tube connection
some more info...
site location: Gurbrü, Switzerland
site location: Gurbrü, Switzerland
Re: tube connection
Seams the ü makes problems. This used to work. Try a file and path name without special character like ü. May be we indroduced this with all the Py3 fixes and broke Py2.
Re: tube connection
BTW: cool project!
Re: tube connection
At first sight, this joint look's more reliable
But, unfortunately it wasn't
But, unfortunately it wasn't
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- Veteran
- Posts: 3129
- Joined: Sat May 20, 2017 12:06 pm
- Location: Germany
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- Veteran
- Posts: 3129
- Joined: Sat May 20, 2017 12:06 pm
- Location: Germany
Re: [solved] tube connection
Did some tests with a cylinder and 2D-shell elements.
You get good results with netgen and 1.-order elements.
The tube connection is based on one sketch and is parametric.
When changing the sketch, netgen does a remesh automatically.
Meshing needs only 20 sec, calculating less than 30 sec.
So I will use this model for my static calculation of the antenna-mast.
You get good results with netgen and 1.-order elements.
The tube connection is based on one sketch and is parametric.
When changing the sketch, netgen does a remesh automatically.
Meshing needs only 20 sec, calculating less than 30 sec.
So I will use this model for my static calculation of the antenna-mast.
Re: [solved] tube connection
Nice case study Thomas.
I found in other posts that CCX shell stresses (especially at corners and connections) can be very inaccurate. Also: when output is set to 2D then only mid-surface stresses are reported. These do not capture local bending effects.
I found in other posts that CCX shell stresses (especially at corners and connections) can be very inaccurate. Also: when output is set to 2D then only mid-surface stresses are reported. These do not capture local bending effects.
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Re: [solved] tube connection
Hi Harry,
thanks for the hint.
But in this case I must live with errors. The problem is:
For the existing mast-structure we get absolutely no documentation
(no construction-plans, no statics, no material-lists, nothing about the foundation...nothing!)
The network-carrier (I forgot the name) gave the whole document-management to the
former general-contractor. XXX forgot to put a passage into the contract,
that the sub must give them all documents after finishing the contract.
Finishing in this case means: they dont like each other anymore...
Now we are the new rider on the horse...
The CAD-drawing from above is from an other more or less similar mast-structure.
We will make a geometry-check at the site. The biggest problem is the foundation.
How can I detect the rebar structure in a massive concrete block?
What about checking the soil under the foundation?
The good news: antenna-masts like this are designed for a minimim deflection.
The radio-mirrors on top only work, when the rotation on top of the mast is less
then one degree under full wind loading. Otherwise the link to the receiver-mirror
(which can be kilometers away) can break. So you need a high tube stiffness, which
automatically gives a stress utilization below 60 %.
Thomas
thanks for the hint.
But in this case I must live with errors. The problem is:
For the existing mast-structure we get absolutely no documentation
(no construction-plans, no statics, no material-lists, nothing about the foundation...nothing!)
The network-carrier (I forgot the name) gave the whole document-management to the
former general-contractor. XXX forgot to put a passage into the contract,
that the sub must give them all documents after finishing the contract.
Finishing in this case means: they dont like each other anymore...
Now we are the new rider on the horse...
The CAD-drawing from above is from an other more or less similar mast-structure.
We will make a geometry-check at the site. The biggest problem is the foundation.
How can I detect the rebar structure in a massive concrete block?
What about checking the soil under the foundation?
The good news: antenna-masts like this are designed for a minimim deflection.
The radio-mirrors on top only work, when the rotation on top of the mast is less
then one degree under full wind loading. Otherwise the link to the receiver-mirror
(which can be kilometers away) can break. So you need a high tube stiffness, which
automatically gives a stress utilization below 60 %.
Thomas
Re: [solved] tube connection
Uh oh. Yep I have seen that happen beforethschrader wrote: ↑Sat Dec 01, 2018 3:06 pm ...forgot to put a passage into the contract,
that the sub must give them all documents after finishing the contract.
How did you create the model in FC? I see various tubes and rings. How did you create those surfaces and stitch them together?