Large deformation analysis with cable-like elements

Hello,

I'm using the LaDeform component to approximate large-deformation behaviour of a tensile membrane with cables. Unfortunately, my arrangement of cables is such that in some load cases the cables would want to take compression - which they obviously cannot. Is there a simple way to eliminate compression/tension elements in each iteration step of the LaDeform analysis? I began looking at scripting it, but couldn't find a way to access each iteration step in the code.

One other question - when I model a shell with a material with a low shear modulus in comparison with it's Youngs modulus, Karamba fails to analyse. (E.g. E=9000 MPa, G=500MPa) Is this due to instabilities in the solver?

Regards,

Lucas

Replies to This Discussion

Permalink Reply by Karamba3D on November 19, 2013 at 11:14am

Hello Lucas,

one thing you could try is to start with a small deformation analysis, then plug the model into the TenComElim-component to clean it from compressive cables, reanalyze it, and so forth. Finally use the LaDeform-component on it.

In Karamba 1.0.4 the large deformation analysis is purely incremental. You could simulate that by placing multiple Analysis-components in a row feeding each with the deformed Model of its predecessor which can be retrieved from the ModelView-component.

Yes there is a problem with shells of low shear modulus in Karamba 1.0.4. I haven't had time yet to give it a close look.

Best,

Clemens

Permalink Reply by Thomas Dührsen on December 14, 2017 at 3:32am

Hello Clemens

I'm new to Karamba and would like to use it for membrane structures. Has the problem with shells of low shear modulus in Karamba 1.0.4 mentioned in this post been fixed in the meantime or is it still pending?

Regards

Thomas

Permalink Reply by Karamba3D on December 15, 2017 at 10:17am

Hello Thomas,

I think the problem had to do with the fact that the transverse and in-plane shear modulus can not be specified independently in Karamba up to version 1.2.2. This will be solved in Karamba 1.3.

Best,

Clemens

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