Assign different materials and thicknesses to shell

Grasshopper Karamba3D
1

Dear experts,

I´m trying to assign two different materials and several thicknesses to a cylindrical shell. In the file VariableCrossSec.gh (77.4 KB), you can check that despite I feed CrossSection component with one list of materials and other of thicknesses for each shell element, Karamba only seems to consider the last material. Please, would you help me?

VariableCrossSec1
VariableCrossSec11808×767 419 KB

  1. The different thickness are always properly considered, i.e. shell thickness lineally increases from base to top and the last ring of shell elements is extra-thick to prevent buckling. Both lists are in-register and contain the same number of elements (the two bottom-right panels in the figure).

  2. When I input one single material (MySteel) together with a list of different thicknesses to CrossSection component everything works as expected, i.e. the shell thickness lineally increases from base to top and the last ring of shell elements is extra-thick to prevent buckling.

  3. However, when I also provide a list of materials with one entry per shell element and only two different materials (MySteel and Dummy), just the last material (Dummy) is used for the whole shell. This is evident since one material is 100 times lighter than the other. Accordingly, the mass of the whole shell is 150417.165 kg when just the heavier material (MySteel) is used, and unexpectedly, 1504.17165 kg if the list of MySteel and Dummy materials is provided.

Would you tell me what´s wrong? Thanks a lot!

2

Hi, thank you for the message. We have taken a look at the example and it seems there is a small bug with the calculation of the total mass of the structure. This should not affect the results however we will fix the bug and will get a new release out in the next days.

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3

Hi Matthew, I´m glad to hear you´re working on it. Thanks for your help! Your software is awesome anyways (with or without such a tiny bug) :slight_smile:

So I understand that the weight loads associated to both different materials are being properly considered in the FEA but only total mass is wrong. Am I right? Thanks!

4

Hi @Vigardo,

we have fixed the bug and you can download a new release from http://www.karamba3d.com/nightly-builds/karamba_LATEST_VERSION/.

With this example you will also see that the weights of the different material properties are calculated.
VariableCrossSec_MT_2.gh (43.9 KB)

Please let us know if you still encounter any issues.

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