Calculix: beam element actually a 3D solid?

[Bausk]

Hello,

as far as I know, (and the CalculiX manual seems to support it) the B32 element in CalculiX FE library actually is a 20-node 3D solid.

To my understanding (and as have been in FE software I've used before), a 'true' 1D beam element in FEA has a precise analytic solution, while solids haven't.

To those of you that have got any experience with CalculiX, did this feature ever lead to any real problems with results precision?

Thanks and regards,
Alex.

Alex Bausk
Structural engineer

http://bausk.wordpress.com

 

[GregLocock]

I can only suggest you run a few single elements model to check. I'd be very pleased to see a good beam element in calculix.

If you look back on their yahoo group you'll see some test cases I ran demonstrating why a beam element could not be approximated at the time by the existing elements in their library.



Cheers

Greg Locock

SIGlease see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[Bausk]

Greg,

thanks for your input.
I found the discussion you've mentioned on Yahoo groups, as well as some pdfs. One of my first thoughts was, too, possible problems with the torsional behavior of a beam.

I wonder if anyone has actually made any further study or developed any workarounds for this problem since that thread, which is 3 years old by now.
Maybe I'll come up with some ideas when I'm done studying the subject. CalculiX is too much fun to let it be spoiled that easily.

Regards

Alex Bausk
Structural engineer

http://bausk.wordpress.com

 

[kellnerp]

I know CalculiX uses the 20 node brick for it's shell elements. You have to turn on body visualization to see stresses on top and bottom surfaces when you use their shells.

There is nothing to stop you from writing your own beam element.

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