Origami and the art of structural engineering
From military shelters and solar arrays to batteries and drones, engineers continue to prove that origami can be the inspiration for more than just paper cranes. The latest creation inspired by the ancient art of paper folding is a new "zippered tube" design that forms paper structureswith enough stiffness to support weight, but can be folded flat for shipping orstorage.
Designed by researchers from the Universityof Illinois at Urbana-Champaign, the Georgia Institute of Technology and theUniversity of Tokyo, the zipper tube relies on an origami technique calledMiura-ori folding. This is a method where zig-zag creases on a sheet of paperallow it to fold into an extremely small area
Individually, pieces of paper with Miurafold creases are highly flexible and can be folded flat, but by gluing two ofthem together, the researchers created a tube that is stiffer and doesn't foldin as many directions. Then, by interlocking two tubes in a zipper-like wayresulted in a structure that is much stiffer and more difficult to twist orbend.
"Thegeometry really plays a role," says Georgia Tech professor Glaucio Paulino."We are putting two tubes together in a strange way. What we want is astructure that is flexible and stiff at the same time. This is just paper, butit has tremendous stiffness."
The crease patterns of a Miura fold form azigzag of parallelograms and the angle can vary between different sheets. Theresearchers say the zipper configuration will work even with two tubes thathave different angles, which allows them to combine tubes with differentgeometries to make three-dimensional structures, such as a canopy or atower.
"Theability to change functionality in real time is a real advantage inorigami," adds Illinois graduate researchers Evgueni Filipov. "Byhaving these transformable structures, you can change their functionality andmake them adaptable. They are reconfigurable. You can change the materialcharacteristics: You can make them stiffer or softer depending on the intendeduse."
Although the researchers demonstrated thetechnique using paper prototypes, they say it could also be applied to otherthin materials, such as plastic and metal. Additionally, the technique isscalable and could be used in anything from microscopic robots and biomedicaldevices, to buildings and bridges.
"Allof these ideas apply from the nanoscale and microscale up to large scales andeven structures that NASA would deploy into space," says Paulino. "Dependingon your interest, the applications are endless. We have just scratched thesurface. Once you have a powerful concept, which we think the zipper couplingis, you can explore applications in many different areas."
Andfurther exploration is what the researchers plan to do, by examining newcombinations of tubes with different folding angles and applying the techniqueto different materials.
Theteam's work was published in the Proceedings of the National Academy ofSciences.