Portable homes may not be too far off - a team of researchers from Harvard University has created a unique type of foldable material that can change size, volume and shape to a degree never before seen in such a material. Amazingly, it can fold into a flat form and withstand the weight of an elephant without breaking, and afterwards morph upright and undergo a subsequent task.
"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," said Johannes Overvelde, first author of the paper.
Using an origami technique called snapology, the team designed the material using extruded cubes with 24 faces and 36 edges, allowing it to be folded along its edges to change shape.
Over both theoretical and experimental tests, the team demonstrated that the cube can become deformed and morph into numerous shapes by folding certain edges. These edges act like hinges and along with the embedded pneumatic actuators, specific hinges can be deformed, eliminating the need for external input to initiate changes in shape and size.
The team took 64 of these individual cells and connected them into a 4-by-4-by-4 cube with the ability to grow, shrink and adapt its shape globally, as well as change orientation and fold flat. This unique design allows the material to have varying levels of stiffness - in one shape, the material may be easy to bend, whereas in another, it is extremely rigid.
"We not only understand how the material deforms, but also have an actuation approach that harnesses this understanding," said Katia Bertoldi, who led the research. "We know exactly what we need to actuate in order to get the shape we want."
The material has the ability to be embedded with any kind of actuator, including thermal, dielectric or water, giving it plenty of potential to help in the creation of new deployable, transformable structures.
"This structural system has fascinating implications for dynamic architecture including portable shelters, adaptive building facades and retractable roofs," said Chuck Hoberman, co-author of the study. "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."
The findings were published in the March 11 issue of Nature Communications.
