Cable-Stiffened Pantographic Deployable Structures Part 2: Mesh Reflector

Abstract

The general concept of deployable structures based on pantographs that are deployed and stiffened by means of cables is applied to the design of the support structure for a large mesh reflector. The two main components of this structure are a cable-stiffened pantographic ring that deploys and pretensions a cable network that, in turn, provides a series of stiff, geometrically accurate support points to which a reflective wire mesh or flexible membrane would be connected. The pantographic ring is a highly redundant structure with an internal mechanism that permits synchronous deployment without any strain in the rods. The geometric conditions that have to be satisfied in order for an n-sided ring to fold without any strain are investigated, including the effects of joint size. An experimental model has been designed and tested. In the folded configuration, it has a diameter of 0.6 m and height of 1.2 m; in the deployed configuration, it has a diameter of 3.5 m. Stiffness and deployment tests on this model have shown its behavior to be linear and the maximum shape error to be ±0.3 mm.