# Composite construction analysis

I would like to get into engineering and analysing architectural constructions using GH. I learned basic structural mechanics in Bachelors but other than that i feel like a complete novice.

I plan on starting from the basics, but ultimately i would like to be able to run analyses on experimental composite constructions: different types of elements connected to form a structure (wooden beams, steel beams, concrete slabs), check stability, check stresses. It doesn’t have to be 100% accurate. Basically i want to learn while playing, as if building a physical model.

Am i correct in thinking Kangaroo might be a good place to start? Does it allow stress analysis? Any tutorials on composite constructions? Other tips are also welcome.

Kangaroo is a good place to start to get a ‘feel’ for structures. The original Kangaroo used ‘pure’ Dynamic Relaxation (DR) which basically looks at the residual forces in any system and iterates accelerations based on these (akin to finite difference method) - the smaller the timestep, the more accurate the results but the longer it takes to solve. This is a useful method for systems with large deformations. Kangaroo 2 uses a kind of ‘enhanced’ version of DR but more geared towards minimising energy states (for speed and wider flexibility) and a much more advanced damping system, but it’s kind of similar. Personally I like these iterative methods because they reconstruct how nature ‘calculates’ in real life in some regards, like a huge parallel computer, but they can be kind of slow for certain situations - volumetric shell elements for example. Some examples are here, albeit they are a bit old now and there are probably better things around the forum: GitHub - Dan-Piker/Kangaroo-examples: Example grasshopper definitions for the Kangaroo plugin

Now Kangaroo itself is not necessarily geared towards getting quantitative results (such as axial and bending stresses, utilization, buckling, etc.), however the K2 Engineering plugin by Cecille Brandt-Olsen is a great add-on that uses Kangaroo goals to analyse structures. This takes into account material properties, which you can specify. You can find it here, with examples: GitHub - CecilieBrandt/K2Engineering

The other thing you should probably do if you’re interested in this world is try a decent realtime finite element solver. These work by making a huge stiffness matrix containing elements (bars, shells, etc.), using shape functions, and solving it behind the scenes to give all the forces/stresses/buckling modes, etc. I think most people on here would recommend Karamba3D for this purpose which is very cheap for non-commercial use: https://karamba3d.com/ but there are other really good ones such as Alpaca4D and Kiwi!3D that would be worth trying out which I think are for free.

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Thank you John for your elaborate response! Good to have some background info as well. I’ll check out these programs, step by step.