Karamba mass incorrectly measured?

Grasshopper Karamba3D
1

Hi,

I have a precast panel 7281 kgs heavy.

When I built my model in Karamba, the mass that gives me is very high. The resultant stresses are also very high. Can someone tell me why this is happening?

Thank you in advance.

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2

Hi, there are two things to note in Karamba3D, the default units are meters for any geometry you input. You can change this in the program settings. Also, if you want to analyse shells, you need to input the axis surface and not the volume, at the moment, Karamba3D calculates this as though you have a consistent thickness of 1cm for the entire mesh

1 Like
3

Hi Matthew,
Thank you very much for your response. The shell analysis is working now for me.
However, I have another question. My shell (precast panel) is supported in the following way:

  • 4 points restrained in Y. (IN & OUT) Ty
  • 2 points restraint in Z (Vertical supports) Tz. However, these supports are not located within the shell plane. They are located at 0.3m to the back of the panel (see sketch). This will create additional pull-out forces in the 4 restraints in & out and generate additional stresses in the panel.

How can SUPPORT ECCENTICITY be set in Karamba?

I appreciate any help you can provide.

Lucia,

Shell analysis
Shell analysis931×704 14.5 KB

4

Hi @Lucia_Calvo_Orte,
I would take account of the eccentricity via beams. In order to avoid a stress singularity at the connection between beam and plate embed a short beam piece in the plate for a more realistic stress distribution there.
– Clemens

5

Hi Clemens.

Thank you for your response. I have now created my model, and the assembled model is composed by:

  • 1 MToShell

  • 2 Beams representing the lever arm, with the endpoint being the vertical support of the shell.

However, when I try to set these 2 points as the vertical support, the error the node where supports are located cannot be found appears in the script. Please see the attached file. Could you please let me know if there is any way to solve this?

I appreciate any help you can provide.

Prueba 05.09.2023.gh (28.8 KB)

Query 1
Query 11912×764 149 KB

Kind regards,

Lucia,

6

Hi, you should check that you flatten all the inputs in the AssembleModel component, I can see that you have multiple branches in your data.

Also if you still have errors, check to see if that particular support is actually a node in your model.