Shell/Beam interaction ?

Hi all,

I am currently working on a model with two main elements : a lattice grid and shell plates.

The shell plates are composed of two layers of metals with different thermal coefficients. When applying a temperature load the shell curves.

The goal of my work is to incorporate those shells in a lattice system with very low stiffness and make the shells "push" the lattice.

In Karamba, the lattice is defined as a network of beams with circular cross sections. The bimetallic sheets are shells.

The problem I have is that when applying the temperature load, the shell deforms but seems to be detached from the lattice. I am attaching an image of a simplified model, to make it clearer. anybody has an idea on how/why the shell and the beams don't stay together ?

Thanks,

Yousef

Attachments:

karamba forum.jpg, 834 KB

Replies to This Discussion

Permalink Reply by Robert Naguschewski on September 9, 2014 at 11:05am

Hi Yousef,

did you input the beams and shell elements as a flat list into the 'element'-input of the 'assemble model' component? In this case, they should stay together, if they share the same nodes.

Otherwise, posting your (simplified) gh-file makes it easier to find the problem.

Cheers,

Robert

Permalink Reply by yousef anastas on September 9, 2014 at 12:02pm

Hi Robert,

thank you for your answer. Yes all elements are flattened. I am attaching the simpliffied grasshopper definition as well as the 3dm file.

Thanks

Yousef

Attachments:

19-for forum.gh, 79 KB
for forum.3dm, 106 KB

Permalink Reply by Robert Naguschewski on September 9, 2014 at 3:39pm

Hi again,

I don't know if that is what you want but now all the beams are deformed along with the shells. I just changed the 'LDist'-input in the 'assemble model' component from 5.0e-8 to 5.0e-6 which is still smaller than the short rods you are using but big enough to recognize the common nodes.Cheers,

Robert

Permalink Reply by yousef anastas on September 10, 2014 at 2:45pm

Hi robert ,

Thank you very much for your help! When I change the Ldist it works better ! I still have one issue to solve : the displacement of the shell is completely different with and without the grid, which is normal but the idea is to decrease the stiffness of the grid to have a considerable deformation of the shell.

I'll try to see if that's possible and let you know !

Thanks again

Yousef

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