A sheet of paper can bend, twist, and tear easily. But folded several times, it becomes stiff and can support objects many times its weight. That’s the basic idea behind “origami engineering,” an emerging technique in structural engineering that’s based on a centuries-old Japanese art form.
Researchers at Georgia Tech, the University of Illinois, and the University of Tokyo have come up with a new, origami-inspired structural-support configuration called “zipper tubes,” long tubes with zigzagged creases. On their own, the tubes are flexible and can bend into a “U” shape. But when coupled together, the structure can be a hundred times stronger than the original material used to make the tubes, says Evgueni Filipov, a graduate engineering student at the University of Illinois. “We’re basically able to eliminate all those twisting, bending, and other types of deformations to make a nice stiff structure, like a beam,” he says. Filipov and his colleagues built their prototypes out of paper, but he says he’s excited about trying the technique with thin sheets of metal or plastic.
At the same time, the tubes maintain their “origami” element, which means engineers can easily manipulate those characteristics as they see fit. “The structure [is] able to change what it does, change its characteristics, and change its property,” Filipov says. “So you can make them flexible or stiffer at times by doing some type of manipulations.” He and his colleagues Glaucio Paulino and Tomohiro Tachi published their findings earlier this month in Proceedings of the National Academy of Sciences.
The zipper pattern is based on an origami technique called Miura-ori folding, in which a sheet of paper is be folded into a compact square in such a way that it can be opened and closed in one swift motion. The zig-zag creases not only make the material stronger but also impart a mechanical property. That means the structure can be folded flat for easy storage and then expanded for fast deployment.
“The ability to be able to stow the materials in a very compact space, then having it deploy into a large functional 3D structure, that’s the number-one thing for space-exploration applications,” Filipov says. Indeed, the Miura-ori method was invented by Japanese astrophysicist Koryo Mirua, who was trying to make solar panels and satellites compact and easy to transport.
But there are advantages on Earth, too. “We see this that could have applications on a large scale for civil engineering, where you have structures that you pre-assembled on a site, loaded on to a truck, and shipped to a specific location,” Filipov says.
The researchers believe this zippered tube will especially come in handy during disasters. “If you have a disaster, you might already have the bridges being built somewhere,” he says. “[If] a bridge gets washed away by a hurricane, we can go quickly onsite and deployed a bridge.” Or, the structures could quickly be carried in to construct temporary shelters.
You can see the zippered tubes in action in this video: