Tower structure optimisation with Karamba3D using Anemone recursive looping for wind loads

Recursive looping - Anemone from Biaggio on Vimeo.

I used recursive looping method to optimise lattice tower members. The problem I was facing with is the effective projected area of the tower structure (EPA_s)

When Karamba cross section optimiser is finding the most weight-efficient section for the given load then the actual EPA_s is just been calculated. The issue here is that one of the main load on a lattice tower is from the wind pressure. So the wind load is based on the EPA_s which we can get only after optimising the sections. With other words, one of our input is based on an output from the design.

This can be solved (for instance) with a recursive looping. The recursive looping work as per the following steps:

• start the loop with an arbitrary wind pressure value (in this case 400N/m linear load on the members)
• run the analysis
• optimise the members
• get the effective area of the members
• send them back in the loop for wind load generation
• repeat from step 2.

At the Anemone container we can define the number of loops (S). I found it sufficient to apply 6 loops in this case. After 4-5 loops no more optimisation is observed regarding the total weight of the structure. 

One thing is also important to be mentioned. Since I am using Galapagos as evolutionary solver, I just did not want to run the loops manually. For an automated optimisation, one of the Galapagos input has been used as trigger for the Anemone loop. Which is a useful stuff ;) (I have tried HoopSnake before but without success)

Since my definition is part of a proprietary solution, I'm unable to share the .gh file. But I hope it still can give some hint what can be done by these components.