There is a house that you can fit into a backpack, and also a wall that can suddenly turn into a window at just the flick of a switch, say Harvard scientists, who have designed a new kind of shape shifting foldable material that is versatile, self-actuated and tunable.
This remarkable material can change shape, size and volume. It can fold out flat to withstand the weight of an elephant jumping on it without breaking – not even a crack – and then it pops right back up, ready for the next task.
Study leader, Katia Bertoldi, the John L. Loeb Associate Professor of the Natural Sciences at the Harvard John A. Paulson School of Engineering and Applied Sciences(SEAS), and colleagues wrote about their research and what the amazing material can do in the prestigious journal Nature Communications (citation below).
Harvard scientists have creaed a new type of foldable material that is versatile, tunable and self actuated. (Image courtesy of Johannes Overvelde/Harvard SEAS)
Incredible material that shape shifts
First author, Johannes T. B. Overvelde,, a graduate student in Bertoldi’s laboratory, said regarding the material:
“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.”
The structure was inspired by snapology – a mixture of origami-like activities for children aged 1 to 14, using building toys and technology that combine play with education. It is made from extruded cubes with twenty-four faces and thirty-six edges.
Like in origami, you can fold the cube along its edges to change its shape. The researchers demonstrated, both theoretically and through practical experiments, that the cube can be deformed into several different shapes by folding specific edges, which act like hinges.
The structures can continue changing endlessly into a virtually infinite number of different shapes and forms. (Image: seas.harvard.edu)
Cube transforms with no external input
They embedded pneumatic actuators into the structure, which can be programmed to deform certain hinges, changing the cube’s size and shape, and without any need for external input.
Prof. Bertoldi, Mr. Overvelde, Chuck Hoberman, of the Harvard Graduate School of Design, and James Weaver, Senior Research Scientist at the Wyss Institute for Biologically Inspired Engineering at Harvard University, connected sixty-four of these individual cells to create a 4x4x4 cube that shrinks and grows, changes shape globally, alters the orientation of its microstructure, and folds completely flat.
As the structure’s shape alters, it also changes stiffness, i.e. you can make a material that is very stiff or pliable using the same design. These actuated changes in the properties of the material add a fourth dimension to it.
Scientists easily control shape they want
Prof. Bertoldi said:
“We not only understand how the material deforms, but also have an actuation approach that harnesses this understanding. We know exactly what we need to actuate in order to get the shape we want.”
The material can be embedded with any type of actuator, including dielectric, thermal or even water.
The structures are inspired by an origami technique called snapology. (Image: seas.harvard.edu).
Dr. Weaver, who runs the Wide Field Electron Optics Laboratory, said:
“The opportunities to move all of the control systems onboard combined with new actuation systems already being developed for similar origami-like structures really opens up the design space for these easily deployable transformable structures.”
Prof. Hoberman, Lecturer in Architecture, GSD. Extensive background in design and manufacture of transformable structures, said:
“This structural system has fascinating implications for dynamic architecture including portable shelters, adaptive building facades and retractable roofs. 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.”
Mr. Overvelde said:
“This research demonstrates a new class of foldable materials that is also completely scalable. It works from the nanoscale to the meter-scale and could be used to make anything from surgical stents to portable pop-up domes for disaster relief.”
In an Abstract in the journal, the authors wrote:
“The proposed metamaterial can be used to realize transformable structures with arbitrary architectures, highlighting a robust strategy for the design of reconfigurable devices over a wide range of length scales.”
The research was funded by the National Science Foundation, the Materials Research Science and Engineering Centre, and the Wyss Institute through the Seed Grant Program.
Citation: “A three-dimensional actuated origami-inspired transformable metamaterial with multiple degrees of freedom,” Sergio A. Becerra, James C. Weaver, George M. Whitesides, Johannes T.B. Overvelde, Twan A. de Jong, Chuck Hoberman, Yanina Shevchenko & Katia Bertoldi. Nature Communications 7, Article Number 10929. 11 March 2016. DOI: 10.1038/ncomms10929.
Video – 3-D Material that Folds, Shrinks and Bends on its Own