Mechanical Joineries for Deployable Reciprocal Shells Through Auxetic Behaviour (DR STAB)

Abstract

Double-curved shells are admired in architecture for their strength, elegance, and efficiency, yet they remain difficult to build, costly to fabricate, and often impossible to reuse once completed. Conventional approaches rely on custom components and rigid geometries that limit flexibility and increase labor demands. Addressing these challenges requires new systems that combine structural efficiency with adaptability. One promising direction lies in bringing together two powerful principles: reciprocal framing, which distributes loads through interdependent members, and auxetic geometries, which expand and contract in controlled ways. When integrated, these principles open the possibility of creating shells that can be flat-packed, deployed into complex three-dimensional forms, and retracted for reuse. The key to achieving this lies in mechanical joinery. In this study, joints are designed not as secondary connectors but as the main drivers of motion and stability. Through a combination of digital modelling and physical prototyping, systems such as ratchets, one-way bearings, and hybrid locking mechanisms were tested to guide expansion, rotation, and locking. The findings highlight a pathway toward adaptable, reusable architectural systems that minimize material waste and assembly effort. Potential applications include temporary architecture, disaster relief structures, and remote construction. By linking geometric intelligence with mechanical precision, this work lays the foundation for a new class of deployable and sustainable building systems.