Lecture 12: Tensegrities & Carpenter's Rules

MIT 6.849 Geometric Folding Algorithms: Linkages, Origami, Polyhedra, Fall 2012
Instructor: Erik Demaine

This lecture covers infinitesimal rigidity and motion, and tensegrity systems as an extension of rigidity theory. The rigidity matrix, equilibrium stress, and duality are introduced, and a proof to Carpenter's Rule Theorem is presented.

License: Creative Commons BY-NC-SA

[jamesking]

d(v) - d(w) is the relative motion of v and w as viewed from w

[Rayquesto]

I’m learning this as a structural engineer. I suppose if you want to understand that bit from a similar background about stresses and struts/cables, basically we call a structure with the members that are allowed to fail in compression, tension only structures. When that is modeled, the compression is ignored and that force is zeroed out that would normally be in certain members and you can get that equivalent structure with only tensegrity. This does not mean those member could also have tension under a tension only model.

[Rayquesto]

46:30 that’s an archaic equilibrium method (graphic statics) done in the 50s in structural engineering school. Haha But certain professors like to bring it up and say that is makes analyzing structures simple without Much computation. I believe James Clerk Maxwell is mentioned as well.

[coalyboi]

idk what hes saying i came here to understand carpenter’s rule