Focus: Video—Tunable Origami
Origami is not just for making paper sculptures; engineers are developing origami-inspired structures that unfold in outer space and inside blood vessels. Now researchers led by Glaucio Paulino of the Georgia Institute of Technology in Atlanta have demonstrated a new folding pattern that produces a 2D material whose mechanical properties can be tuned over a wide range. The periodic folding pattern consists of a network of creases, some of which can produce either a “mountain ridge” or a “valley,” depending on which way they fold. Switching a crease from mountain to valley causes a change in the material’s so-called Poisson’s ratio, which describes the degree to which stretching a material along one direction will cause it to shrink along the perpendicular direction. The researchers could enact a wholesale switch to all the reversible creases, transforming the material from a positive Poisson ratio (called eggbox mode) to a negative ratio (Miura mode). Or they could perform switches in selected rows in the pattern, which produces a hybrid fold.
Hybrid folds could lead to structures with a new level of versatility, says Paulino. For example, some concert halls have adjustable, origami-based acoustic structures for controlling sound projection. With a wider variety of configurations, such structures could provide a more customized musical experience. Paulino is also interested in designing an origami-based drone crash protection system that could be modified according to the flight conditions.
This research is published in Physical Review Letters.
–David Ehrenstein
David Ehrenstein is the Focus Editor for Physics.