Configuration and Deformation Control of a Hybrid Cable Bending-Active Structure

Reconfigurable structural systems aim at spatial adaptability in respect to changing functional, aesthetic or other architecture-oriented objectives. At the same time, adaptive systems are called to reserve the structure’s load-bearing capacity according to external loading criteria and scenarios. While pantograph structures have proven promising in these critical aspects, bending-active elements discard multiple local hinges and number of members by replacing them with single members of enhanced elastic bending deformability. This soft approach renders the possibility to form complex-, single- or double-curved primary structures from straight or planar members, providing in this respect an alternative frame- work to realize constructions of increased transformability and diversity in forms. The development of hybrid systems composed of bending-active members using secondary cables as means of stability and control, enables adjustability of the systems’ form-found shape and deformation control. In the current paper, a hybrid cable bending active structure is investigated at the level of prototype unit and overall structure. On the horizontal plane, the unit consists of a pair of vertically oriented PTFE lamellas, interconnected at mid-length and deformed in inverse direction to form a curvilinear symmetric shape. Cable and strut elements stabilize the primary elastic members by connecting them at both ends in longitudinal and transverse direction, respectively. The overall structure acquires three arc-like configurations, controlled by the secondary system of cables and struts positioned at the periphery of the primary system’s span. All systems are examined in their form-finding and load-bearing behaviour.