Spaceframe Analysis

About the development of the FEM module/workbench.

Moderator: bernd

Laurie Hartley
Posts: 28
Joined: Mon Feb 27, 2017 5:33 am

Re: Spaceframe Analysis

Postby Laurie Hartley » Tue Mar 12, 2019 10:54 pm

Here they are Thomas
Attachments
Plate C.FCStd
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Plate B.FCStd
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Plate A.FCStd
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thschrader
Posts: 1394
Joined: Sat May 20, 2017 12:06 pm
Location: Germany

Re: Spaceframe Analysis

Postby thschrader » Sun Mar 17, 2019 3:15 pm

Hi Laurie,
did some calculations.
Under self-weight and vertical loading 1 kN each upper node
I get a system-utilization of 94%. All beams wood 10x6 cm.
Self-weight structure (without nodes) is approx 3000 kg.
A wooden node as beam connector wont work, the pressure between the
bolt/hole is too high.
When using steel-tubes 44,5x4,5 mm I get the same self-weight but only
a system-utilization of 43%.
spaceframe_wood_beams_10x6_cm.JPG
spaceframe_wood_beams_10x6_cm.JPG (68.92 KiB) Viewed 255 times
load.JPG
load.JPG (228.94 KiB) Viewed 255 times
normal_force.JPG
normal_force.JPG (434.3 KiB) Viewed 255 times
thschrader
Posts: 1394
Joined: Sat May 20, 2017 12:06 pm
Location: Germany

Re: Spaceframe Analysis

Postby thschrader » Sun Mar 17, 2019 3:19 pm

Laurie Hartley
Posts: 28
Joined: Mon Feb 27, 2017 5:33 am

Re: Spaceframe Analysis

Postby Laurie Hartley » Mon Mar 18, 2019 8:56 am

Thanks Thomas for going to all this trouble. My original intention was to develop a steel structure so I am not too disappointed (or surprised) that the plywood node won’t work because of the pressure at the bolts.

Thanks also for the brochure. I am fascinated by spaceframes and there are quite a few in Melbourne, the city I emigrated to from the UK in 1973. Her is an example:

http://www.adonline.id.au/buildings/collins-place/

Can I ask you two more questions please:

1. Are your images screenshots from the Free Software programme you suggested and which I have downloaded?
2. When you say the system-utilisation of the steel version is 43% (please forgive my lack of knowledge) what exactly does that mean in layman’s terms?

I have downloaded and installed the so 3D Framework Software and you have enthused me to see if I can use it.
This has been a great learning experience for me.

Thanks again Thomas.
thschrader
Posts: 1394
Joined: Sat May 20, 2017 12:06 pm
Location: Germany

Re: Spaceframe Analysis

Postby thschrader » Mon Mar 18, 2019 10:38 am

Laurie Hartley wrote:
Mon Mar 18, 2019 8:56 am
1. Are your images screenshots from the Free Software programme you suggested and which I have downloaded?
2. When you say the system-utilisation of the steel version is 43% (please forgive my lack of knowledge) what exactly does that mean in layman’s terms?
Hi Laurie,
answering your questions:
Point 1:
The sreenshots are taken from my commercial 3D-static software called 4H-Frap, see here
https://www.pcae.de/
Modelling 3D-frames is tricky (orientation of beam axis in space, defining hinges between beams...).
I work with 4H-Frap since 25 years and I know the program in detail.
I will try a second run with the free "Framework". Give me some time, Framework is complex.

Point 2:
System-utilization means here: the computed stresses in the beams are compared to the
max allowed stresses. Not more. There are some additional checks necessary, for instance stability.
But the beams are short, that should be no problem.
Thomas
Laurie Hartley
Posts: 28
Joined: Mon Feb 27, 2017 5:33 am

Re: Spaceframe Analysis

Postby Laurie Hartley » Mon Mar 18, 2019 8:50 pm

Thanks again Thomas. I’ll keep an eye out for your findings. :)
thschrader
Posts: 1394
Joined: Sat May 20, 2017 12:06 pm
Location: Germany

Re: Spaceframe Analysis

Postby thschrader » Tue Mar 19, 2019 6:22 pm

Hi Laurie,

I do not really understand how to use the nodes/beams generator tool in Framework.
Filling in the node / beam tables by hand for the whole structure is a lot of work.
So here is a small one for testing..
Rename txt-file to spaceframe001.Framework3D
Start Framework
==> Files/load input
run calculation (press F8)
Hover with mouse-pointer over the menue-buttons until you see
„Graphical output total framework“
Select Normal force, press Open.
Adjust output options.
Have fun.
Thomas
spaceframe001_Framework3D.txt
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mini_spaceframe.JPG
mini_spaceframe.JPG (259.71 KiB) Viewed 127 times
Laurie Hartley
Posts: 28
Joined: Mon Feb 27, 2017 5:33 am

Re: Spaceframe Analysis

Postby Laurie Hartley » Tue Mar 19, 2019 9:20 pm

I certainly will have fun with this Thomas - I hit 70 today so there is enough in this to keep me occupied for another 10 years at least :D

Thanks again for all your help.