Origami may be new key to structures small and large

Researchers at Harvard, led by an Indian-origin scientist, have developed a new technique that uses origami to create foldable 3D shapes, an advance that could be a key to designing pop-up furniture, medical devices and even buildings.

The folding pattern, known as the Miura-ori, is a way to tile the plane using the simplest mountain-valley fold in origami.

It was used as a decorative item in clothing at least as long ago as the 15th century.

A folded Miura can be packed into a flat, compact shape and unfolded in one continuous motion, making it ideal for packing rigid structures like solar panels.

It also occurs in nature in a variety of situations, such as in insect wings and certain leaves.

"The really exciting thing about this fold is it is completely scalable. You can do this with graphene, which is one atom thick, or you can do it on the architectural scale," said L Mahadevan, professor at the Harvard University's John A Paulson School of Engineering and Applied Sciences (SEAS).

The technique can be used to design surgical stents that can be packed flat and pop-up into three-dimensional structures once inside the body; or dining room tables that can lean flat against the wall until they are ready to be used.

"We found an incredible amount of flexibility hidden inside the geometry of the Miura-ori," said first author Levi Dudte, graduate student in the Mahadevan lab.

"As it turns out, this fold is capable of creating many more shapes than we imagined," Dudte said.

"The collapsibility, transportability and deployability of Miura-ori folded objects makes it a potentially attractive design for everything from space-bound payloads to small-space living to laparoscopic surgery and soft robotics," said Dudte.

To explore the potential of the tessellation, the team developed an algorithm that can create certain shapes using the Miura-ori fold, repeated with small variations.

Given the specifications of the target shape, the programme lays out the folds needed to create the design, which can then be laser printed for folding.

The programme takes into account several factors, including the stiffness of the folded material and the trade-off between the accuracy of the pattern and the effort associated with creating finer folds - an important characterisation because, as of now, these shapes are all folded by hand.

"Essentially, we would like to be able to tailor any shape by using an appropriate folding pattern," said Mahadevan.

The research was published in the journal Nature Materials.