Simulate Early, Simulate Often... In Rhino
Sorry guys, been a while. A year of occupational 'detour' (long story) but back to solving structural problems.
3D PDF has been a real hit and it's easy to save out SNS solutions with the SimLab plug in. Simply 'bake' the solution to a Rhino mesh with a texture. Set the renderer to Rhino (not VRay for example), then export the PDF with Simlab. Annotations exploded into lines (that's still a little bug).
The attachment below is a chair back made from recycled PP+30%CaC, BIFMA service load of 890N applied. Deformation set to 1. As you can see there's still some work to be done!
Tried different rib arrangements with linear boxes, honeycomb, triangulation and now this 'cathedral' structure which is starting to show promise.
Admittedly, a very rough design still but progressing. Honeycomb structures were very interesting as they tend to dissipate load - nature makes clever use of them. But in this case I need to dissipate inwards only. May still integrate them.
Two design considerations that have come to the fore are (1) Lightweighting and (2) Recycled materials, which in the case of polymers suffer greatest in the area of impact strength.
SNS has been used to reduce product failure rates to practically zero. I'm not an engineer but recall that traditionally draftsmen were called upon to solve basic stress problems, freeing up engineers to solve complex problems.
Learning fundamental stress equations and testing in SNS is well within the scope of a competent product / industrial designer.
It has undergone a redesign with honeycomb in the center - I have found that tends to dissipate loads well. I've been looking for inspiration in dragonfly wings as they seem to use loads carefully to subtly shape the wing. Will be modelling and SnS'ing that soon.
I'd love to learn how to use RhinoScript with SnSScript. Do you perhaps have a sample project for me to cut my teeth on?
Have started playing with Grasshopper too - awesome! Just love the interface. IMHO David Rutten should head up the Rhino v6 UI team. Is it possible to patch Grasshopper into SnS?
There are a few example scripts in the SnSScript examples forum:
and also in the SnSScript documentation:
These examples discuss using SnSScript to compute simulation properties rather than creating or changing geometry using RhinoScript.
To find examples for editing geometry within RhinoScript, maybe check at rhinoscript.org: http://www.rhinoscript.org/. I've been interested in creating an example where SnSScript is part of an automated geometry modification loop, but inventing compelling and understandable examples takes time. There always seems to be something else that requires attention.
The current architecture of SnS is not amenable to coupling with Grasshopper. Grasshopper and PythonScript are based on Microsoft's .NET programming technology, the direction in which plan to eventually migrate a future version of SnS.
Fantastic, thanks! I'm very excited about the prospect of allowing SnS to self optimise geometry. It contributes directly to the growing demand for 'lightweighting' and recycled materials with impaired mechanical properties.
Let me get my head around your examples and I'll look for a 'real world' problem to solve. What if we started with something simple like a spring? I had such a problem, solved by plugging test values into Excel. It solved the problem; within a year it became a top selling product (PDF attached).
SnS migrated to Grasshopper would be mind blowing. For someone like me familiar with a bit of programming but not actively coding, porting your skills to a graphical interface like Grasshopper gives us a big jump start.
I really wouldn't have felt comfortable designing this chair back, for instance, without SnS.
A spring is a good place to start. It is relatively easy to model while simultaneously being non-trivial. We'll have to limit it to compression springs with a gap between the coils. In the case of your torsion spring with coils touching, the simulation grid will cross the space between coils and the results will be incorrect.
OK, sounds good. I'm teaching at Plastics|SA the whole of this week but should be able to get some good study time in next week, then set up a simulation.
Was also thinking of modeling a (traditional) bow allowing for various limb forms, thicknesses, chords or cross sectional shapes. That's interesting because a bow is simultaneously a spring and a 'gearbox' - the load vector is dynamic.
I think though for now a coil spring will have wider application.