A team of engineers recently found inspiration in the art of origami, creating a material that can fold itself into almost any imaginable shape. The material is able to change not only its shape, but its size and volume as well.
The material, described in Nature Communications, was discovered by Katia Bertoldi, the John L. Loeb Associate Professor of the Natural Sciences at the John A. Paulson School of Engineering and Applied Sciences (SEAS) at Harvard University, James Weaver, Senior Research Scientist at the Wyss Institute for Biologically Inspired Engineering at Harvard and Chuck Hoberman of the Harvard Graduate School of Design.
“We’ve designed a three-dimensional, thin-walled structure that can be used to make foldable and reprogrammable objects of arbitrary architecture, whose shape, volume and stiffness can be dramatically altered and continuously tuned and controlled,” Johannes T. B. Overvelde, a graduate student in Bertoldi’s lab and first author of the paper, said in a press release.
The material is extruded from cubes and consists of 24 faces and 36 edges. Each of the edges acts analogously to hinges, giving the material the freedom to fold along each edge in order to change its shape. The final extruded product is thin-walled, versatile and self-actuated. By implanting pneumatic actuators onto the material, the researchers made control of the each of the material’s properties programmable.
“The opportunities to move all of the control systems onboard combined with new actuation systems already being developed for similar origami-like structures really opens up the design space for these easily deployable transformable structures,” Weaver said in a press release.
The researchers demonstrated the properties of the new material by connecting 64 of the three-dimensional cells to create a 4x4x4 cube. Manipulating the cube along each of its edges enabled the team to change its global shape and the orientation of its microstructure. The researchers were even able to fold it completely flat. The flexibility of the new material is not limited to three dimensions. Changing the structure gives researchers control over a fourth dimension, stiffness. When folded flat, the material can support the weight of an elephant without any deformation, allowing it to be opened back up to a three-dimensional shape.
“We not only understand how the material deforms, but also have an actuation approach that harnesses this understanding,” Bertoldi said in a press release. “We know exactly what we need to actuate in order to get the shape we want.”
Applications for the material have few limitations. It can be embedded into almost any actuator, from dielectrics to water, and has been proven to function not only on the nano-scale but also on the scale of meters. This opens up the new material to any number of potential uses. The team predicts the material will have the greatest impact on dynamic architectural projects, such as portable shelters, adaptive building facades and retractable roofs.
“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,” Hoberman said in a press release.
As research into the material continues, the future may one day see houses folding up to fit into a backpack, or tables becoming chairs at the press of a button.
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