Sunday, July 15, 2012

Tensegrity!

Or, when is an artist a mathematician? If one answer is, "When he crosses paths with R. Buckminster Fuller," you're on the right track!

Today's subject, Kenneth Snelson, a fellow who has proposed -- and built -- new physical-conceptual models of the atom and appears to be the very first man to set up a tensegrity tower, an impossible-looking object that stands tall -- on its own bootstraps. Or tension cables. Have a look!

(I could swear at one time I read the University of Hawaii had an AM radio tower built on this model, but I'm not finding it. Once windload is taken into account, such a structure uses up most of its strength holding up its own weight -- that's the design "trick" to it -- but that's all a tower has to do for an AM station: it's really just a fat piece of wire.)

9 comments:

Alan said...

That would be hard to climb.

Ian Argent said...

I just ran into that term in book two of Hard Magic.

Dave H said...

60 feet? Isn't that about a quarter wave on 75 meters? I wonder if I can get the parts for that at Home Depot.

Roberta X said...

Alan: Depends.

Ian: Larry does his homework!

Dave: Yes, I believe you can.

Ian Argent said...

Also, my kid has one of these - http://www.amazon.com/Manhattan-Toy-200980-Skwish-Classic/dp/B000GI0S4E - which would appear to be an example of a Tensegrity Icosahedron...

It's the little things that keep me reading Mr. Correia's work. And maybe some of the big things (zeppelins, Abominations, that sort of thing)

karrde said...

Now that is a cool idea.

Are there many towers in the wild built on this pattern?

Roberta X said...

Very few. The largest is in Germany.

Anonymous said...

It looks as though it's a bit of a paradox; it has to be fully assembled before it hold any weight. How is that possible to construct? (I guess I'd have to watch one being built.)

Jon

Roberta X said...

Jon, the cables are not one continuous length; the towers can be built in modules, more-or-less stacked using some temporary cables and a conventional crane. I'm not sure if they'd be amenable to a gin-pole but I suspect not.

If you noodle around at Snelson's site, he has some nice tutorials. Modularity of a very simple "kite frame" structure is demonstrated there.

He approaches these structures in a very common-sense way, the kind of "engineering imagination" approach I find appealing.