Why things don't fall down - Art, geometry and engineering
- Date: 10/11/2007
Robert Connelly (Cornell University)
University of Calgary
Why do some geometric shapes hold together, while others are floppy and
fall down? An eggshell and a convex dome are rigid, while polygons,
with four or more sides of fixed length in the plane, flex. The
geometric principles for convex shapes go back to the work in 1813 of
A. Cauchy, one of the preeminent mathematicians of the 19th century.
More recently a sculptor, Kenneth Snelson, has created many large
works, called tensegrities, made of steel struts and cables, where the
struts are suspended in mid-air, and yet, when these tensegrities are
assembled, they are quite rigid. Why don't these structures fall down?
Secrets will be revealed, tensegrity models shown, and participants
will be invited to make their own tensegrities from sticks and rubber
PIMS Distinguished Lecture 2007