House folds up, house folds down
American engineers have designed a new type of foldable material that is versatile, tunable and self actuated with the ability to change size, volume and shape.
Professor Katia Bertoldi from Harvard University said the structure is inspired by an origami technique called snapology, and is made from extruded cubes with 24 faces and 36 edges. It can be folded along its edges to change shape.
The team embedded pneumatic actuators into the structure, which can be programmed to deform specific hinges, changing the cube’s shapes and size, and removing the need for external input. By connecting 64 of these individual cells, the team created a 4x4x4 cube that can grow, and shrink, change its shape globally, change the orientation of its microstructure and fold completely flat.
“We not only understand how the material deforms, but also have an actuation approach that harnesses this understanding,” said Bertoldi. “We know exactly what we need to actuate in order to get the shape we want.”
The team said the opportunities to move all of the control systems onboard combined with new actuation systems already being developed for similar origami-like structures opens up the design space for these easily deployable transformable structures.
Potential applications could include portable shelters, adaptive building facades and retractable roofs. However, because it is scalable, it could also work at the nano-scale and be used to make surgical stents.
“Whereas current approaches to these applications rely on standard mechanics, this technology offers unique advantages such as how it integrates surface and structure, its inherent simplicity of manufacture, and its ability to fold flat,” said Bertoldi's colleague from the Graduate School of Design, Chuck Hoberman.
A single foldable structure comprising six cubes with 24 faces and 36 edges. Image: Harvard Engineering