Multistable inflatable origami structures at the metre scale
Inspiration from origami is drawn to design rigid-walled deployable structures that are multistable and inflatable, providing a direct route for building large-scale inflatable systems that lock in place after deployment and offer a robust enclosure through their stiff faces.
Abstract
From stadium covers to solar sails, we rely on deployability for the design of large-scale structures that can quickly compress to a fraction of their size<sup>1-4</sup>. Historically, two main strategies have been used to design deployable systems. The first and most frequently used approach involves mechanisms comprising interconnected bar elements, which can synchronously expand and retract<sup>5-7</sup>, occasionally locking in place through bistable elements<sup>8,9</sup>. The second strategy makes use of inflatable membranes that morph into target shapes by means of a single pressure input<sup>10-12</sup>. Neither strategy, however, can be readily used to provide an enclosed domain that is able to lock in place after deployment: the integration of a protective covering in linkage-based constructions is challenging and pneumatic systems require a constant applied pressure to keep their expanded shape<sup>13-15</sup>. Here we draw inspiration from origami-the Japanese art of paper folding-to design rigid-walled deployable structures that are multistable and inflatable. Guided by geometric analyses and experiments, we create a library of bistable origami shapes that can be deployed through a single fluidic pressure input. We then combine these units to build functional structures at the metre scale, such as arches and emergency shelters, providing a direct route for building large-scale inflatable systems that lock in place after deployment and offer a robust enclosure through their stiff faces.