PTC load case in a load combination via the Grasshopper API

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1

I am looking for a way to include the forces from the PTC (post-tensioning) cables in my load combinations entirely through Grasshopper.

Currently, only the loads explicitly defined in the Grasshopper script are being included in the combinations, while the internal forces generated by the cables are missing. How can I ensure these cable forces are captured and assigned to a load case within the Grasshopper workflow, without having to manually add them in the FEM- design software after export?

2

Hi @kolnas! :waving_hand:

FEM-Design automatically calculates and generates PTC internal forces and their corresponding load cases. Unfortunately, these load cases cannot be set up parametrically.

One possible solution would be to create the required objects (beams, PTCs, etc.) parametrically, then open the model in the FEM-Design. Create/generate the load combinations manually and save the model to a file. Then add the following steps to your GH script:

  • read the model from the file;
  • deconstruct the model;
  • use the load combinations from the Model.Deconstruct component’s output;

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I’ve attached a sample gh script and the struxml model file containing the generated load combinations.

sample.gh (27.5 KB)

PTC-bar.struxml (10.1 KB)

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Hi @kolnas! :waving_hand:

I was wrong. I’ve just realised that we implemented a solution for FD-generated load cases a while ago. For auto-generated load cases, you need to specify a specific string (its name). In case of PTC, these are “ptc t0” and “ptc t8”.

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I’ve attached a sample Grasshopper script.

sample.gh (41.3 KB)

I apologise for any misunderstanding. However, thanks for raising the question. I also learnt something about our tool :slightly_smiling_face:

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