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Harvard Researchers Create Transforming Metamaterial

In a paper published at Nature Communications last month, Harvard researches propose a new metamaterial that is resilient and strong, able to be compressed flat and then opened back up with no lasting impact to its structure. The versatility is enabled by thin-walled units arrayed in a continuous matrix, permitting it to dramatically alter shape and volume, and to be tuned to specific geometries. It is the result of a cross-disciplinary collaboration within Harvard led by Katia Bertoldi of the School of Engineering and Applied Sciences (SEAS), James Weaver of the Wyss Institute for Biologically Inspired Engineering and Chuck Hoberman of the Graduate School of Design.

In a blog post on the SEAS website Hoberman notes the important practical potential of the research: “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.”

The development of the material was grounded in the work of Heinz Strobl and his field of Snapology, “in which paper ribbons are used to create complex geometric extruded polyhedra,” which in turn is inspired by the ancient art of Origami. Of course Origami and modular structures are irresistible to the designer’s mind and make a regular appearance here on Core77; we featured a highly structural derivation just last fall.

The key with the Harvard work though is the ability to be actuated internally, removing the need for external mechanics to compress or extend it. While the models seen here are pneumatically actuated, the researchers say any kind of actuator would do the job.

Probably most exciting of all is the prospect of scaling it down. The paper states: “In fact, origami-inspired metamaterials at the micro-scale could be manufactured by using self assembly or stress within thin films and by taking advantage of recent developments in hinge construction at small scale for laminate-based mechanisms. This represents a significant advantage for the proposed structures over structures composed of rods connected by rotational joints, which are challenging to fabricate at a very small scale.”

It wouldn’t have to shrink too far to be useful in a surface application on, say, a vehicle’s body. And if you imagine it as the technical underpinning of a morphing skin, then BMW’s gauzy future scenarios suddenly gain a bit more substance!