How does tensegrity work?



I just tried to read a wikipedia article about it and I’m so confused.

In: Physics

A normal substance like a wooden block has several physical qualities that allow it to be used as a building material. The most obvious is resistance to compression, meaning it can hold back something trying to crush it instead of collapsing. Another is resistance to tension meaning it can resist forces trying to stretch it.

Some substances are very good at one of those and very bad at the other. Concrete for example is great at resisting compression but pretty bad at resisting tension. A steel cable is very good at resisting tension but cannot resist compression at all.

“Tensegrity” is just jargon for trying to arrange tension forces such that they resist forces which would otherwise be compression. A simple example is a bicycle wheel: The fork’s connection is always hanging from the spokes of the wheel no matter the orientation, and the wheel’s shape is held by the equal tension of the spokes. To crush the wheel would require the sides of the circle to bow outwards and they are prevented from doing so by the tension of the spokes. Compressive forces are resisted by tension.

The somewhat cool part of this is that materials able to resist tension can often be lighter than those which resist compression, so your wheel with tensioned wire spokes is lighter than one with thick wooden staves that resist compression.