How does the Karamba ''tension-compression eliminator'' component work?

Hello everyone,

I am currently working on my graduation project in the field of structural engineering.

Without getting off-topic, I made a grasshopper model for my design and I use Karamba as FEM solver.
One of the components that I need to use is the tension-compression eliminator.

I briefly know what it does, but I would like to have some more literature/information about background/mechanics that lies within this component.

I really hope some-one can point me in the right direction! :slight_smile:

Kinds regards,

Joris Vleeshouwers

Hello @joris_vhw,
some details regarding the tension-compression eliminator can be found here: 3.5.12: Tension/Compression Eliminator 🔷 - Karamba3D 1.3.3.
In the test examples (see …\Rhino 7\Plug-ins\Karamba\Examples\TestExamples) there is the definition ‘Tension_Compression_Eliminator_Scripted.gh’ which contains a scripted version of the t/c-eliminator.
– Clemens

Dear Clemens, thank you for your fast reply!

Do I understand correctly that the tension-compression eliminator executes a linear elestic analysis multiple times (depending on you reach the max nr. of iterations or no changes occur).

So there is no non-linear behavior involved?

Thank you very much for your help.

Kind regards,

Joris

Dear Joris,
the non-linear behavior comes from switching elements on and off.
– Clemens

Dear @cp1,

Thanks again for you fast reply. I am trying to fully understand this,

So it is correct, that although it looks like (geometrical) non linear behavior, the analysis with the t/c- eliminator is fully Linear. There is no change in stiffness like with cables, which stiffness increase when the geometry changes.

The t/c components performs a Linear Elastic analysis, analyzez afterwards which elements have compression/tension and removes either the compression or tension elements (based on what you selected) and then performs a new Linear Elastic analysis for the new geometry (situation).

It seems I cannot acces the script of the component, you mentioned. I hope you can share them somehow.

Kind regards,

Joris

Dear @joris_vhw,
your description is correct.
Here is the scripted version of the tension/compression eliminator from the Karamba3D examples:
Tension_Compression_Eliminator_Scripted.gh (29.9 KB).
– Clemens