algorithmic modeling for Rhino
karamba is an interactive, parametric finite element program. It lets you analyze the response of 3-dimensional beam and shell structures under arbitrary loads.
karamba is being developed by Clemens Preisinger in cooperation with Bollinger-Grohmann-Schneider ZTGmbH Vienna.
Download the free version for non-commercial use only. In case you want to purchase a commercial license contact us via info@karamba3d.com or read the manual for details.
download, manual:
http://www.karamba3d.com/downloads or
http://www.food4rhino.com/project/karamba
examples (require GH 0.9.0014):
http://www.karamba3d.com/category/examples/
update report/known bugs:
http://www.grasshopper3d.com/group/karamba/page/new-features-and-bug-fixes
Here a beam structure based on stream-lines with bending moments:
More details, manual, examples and download ....
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Started by Llordella Patricio. Last reply by karamba Feb 16.
Hi, as far as I can tell, I cannot accomplish the following in Karamba:- apply a different thermal load for each shell element whilst grouping them for cross section optimization: I can only do one…Continue
Started by Diederik Veenendaal. Last reply by karamba Feb 12.
Comment
Leonardo:
in Karamba 1.0.5 the cross section optimization algorithm only considers normal forces for buckling. The next version (Karamba 1.1.0) takes full account of the EC3 formulas including lateral torsional buckling and interaction values according to annex B.
Best,
Clemens
Clemens, thanks for your quick answer.
I have carefully read the appendix and the way for calculating the buckling length is clear. However I have still one questions:
seems to be that adopting Eurocode3 (eq. 6.47) only the normal forces are compared with the critical buckling load. Am I right?
Can we want take into account both, bending and axial compression, as suggested by Eurocode3 (Eq. 6.3.3)?
Many thanks,
Leonardo
Hi Leonardo,
the Cross Section Optimization component takes into account buckling for members (see the appendix of the Karamba manual). The assumed buckling length is the distance between two nodes that connect to more than three beams or to a support or double that distance in case one end is free. The buckling lengths can be set manually via the 'ModifyBeam'-component.
If you have 'huge' bending moments in your structure then buckling will have little effect on the result.
Sometimes so called global buckling can govern a design (think e.g. of a compressed girder of a truss structure). In such cases one has to guess the buckling length or do a buckling analysis (which will be possible in Karamba 1.1.0).
Best,
Clemens
Hi Clemens,
I need your help! I have a very simple curved geometry, like an arch, composed by several beams. This is a not funicular geometry and there are huge bending moments. I do not understand:
1) if the Cross Section Optimization component takes into account buckling for members in bending and axial compression (6.3.3 - Eurocode 3).
2) if the buckling length corresponds to each beam or to the length of the whole arch or to the distance between supports (local or global buckling.
If instead of an arch, there is a more complex structure, i.e. an arch bridge with tendons and deck, what is the buckling length of the arch adopted by the Cross Section Optimization component?
Many thanks,
Leonardo
Dear clemens
Thanks for the help, I just created a topic discussion and add any comments that we have done so far.
Best regards
Patricio
Dear Patricio,
try to increase the number of shell elements. As mentioned in the manual they are linear elements. A mesh that is too coarse leads to a response which is stiffer than the real structure.
Best,
Clemens
P.S.: Could you please open a new discussion on the topic? These discussions are easier to find and follow for other people who face a similar problem.
Dear clemens
I was doing a rough estimate of the deformation, and I can not achieve the same result with Karamba.
When I make a rough estimate of the result with Karamba beams and mine are very similar, I think the problem is when I connect the shell, because there are no similar results.
I sent the GH file, and an image of the calculation
The structure is concrete
The result I get is 0.58cm
thank you
Patricio
Perfect, that is just what I needed, thank you very much for your help, I'll keep working and any questions write again, it is very useful for students to understand the structural performance.
best regards
Patricio
You could use the 'Mesh Edges'-component to retrieve the naked edges and turn them into beams - see attached file: 91014Example1_cp.gh
Best regards,
Clemens
Hello, succeeds in creating the mesh to the slab, and built the beam segment, but when I see the deformations are not expected because the beam is deformed as the slab.
Thanks for the help
PS: maybe I'm using the program for a type of structure that is not the most appropriate, as I saw in the examples of other structures. But this type of structure is that students taught
best regards
Patricio
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