Bending-active reciprocal structures based on equilateral polyhedral geometries

Abstract

As mutually supported beam structures, reciprocal frames limit the number of components that are joined at each connection to two. However, this system of intermediate connections introduces undesirable bending moments in the beam elements. By utilising elastic deformation to create curved geometries, bending-active structures show the potential of bending as a formation process. Moreover, the curved geometries showcase an increased resistance to bending. Despite the apparent potential, only a few geometric explorations of bending-active reciprocal structures exist. Therefore, we investigated the principle by developing a design methodology based on polyhedral shapes. As this work is part of a research on transformable, rapidly assembled structures, the focus lies on simplicity of the connections, uniformity of the components and reconfigurability. This paper discusses the development of a kit of parts of reciprocal bending-active components based on a selection of polyhedral dome types. To simplify the assembly of the structures and avoid the manual bending of the components on site, we introduce the concept of a double-layered, pre-bent component. Finally, this paper presents the development, fabrication and assembly of the ReciPlyDome, a full-scale prototype of a bending-active reciprocal dome with double-layered components. Preliminary analyses of the load-bearing behaviour show the potential of these systems for material-efficient, lightweight structures. The research presented in this paper contributes to the understanding of bending-active reciprocal frames as a structural principle for temporary and rapidly assembled structures.