Cable-stiffened foldable elastica for movable structures

A structural element is proposed, made of a row of rigid voussoirs joined by a passing through cable. When the cable is tensioned, the ensemble acquires stiffness and, for appropriate contact profiles of the voussoirs, the response of the element under applied loads is governed by the same equations of Euler's elastica or, in equivalent terms, of a non-linear spline. Releasing the connecting cable, the structure is loosened and can be closely packed. With this system one can reproduce, at least in principle, any desired profile in the “stiff” configuration, and construct free form foldable surfaces of any shape.