A toolkit for transformable materials

Metamaterials - materials whose function is determined by structure, not composition - have been designed to bend light and sound, transform from soft to stiff, and even dampen seismic waves from earthquakes. But each of these functions requires a unique mechanical structure, making these materials great for specific tasks, but difficult to implement broadly. But what if a material could contain within its structure, multiple functions and easily and autonomously switch between them? Researchers from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) and the Wyss Institute of Biologically Inspired Engineering at Harvard University have developed a general framework to design reconfigurable metamaterials. The design strategy is scale independent, meaning it can be applied to everything from meter-scale architectures to reconfigurable nano-scale systems such as photonic crystals, waveguides and metamaterials to guide heat. 'In terms of reconfigurable metamaterials, the design space is incredibly large and so the challenge is to come up with smart strategies to explore it,' said Katia Bertoldi , John L. Loeb Associate Professor of the Natural Sciences at SEAS and senior author of the paper. 'Through a collaboration with designers and mathematicians, we found a way to generalize these rules and quickly generate a lot of interesting designs.' Bertoldi and former graduate student Johannes Overvelde, who is the first author of the paper, collaborated with Chuck Hoberman , of the Harvard Graduate School of Design (GSD) and associate faculty at the Wyss and James Weaver , a senior research scientist at the Wyss, to design the metamaterial.