The primary source of human inspiration is nature. To a generation that grew up with cartoons and games all around them, maybe it is not so much the case. This leads to fun discoveries and innovative solutions, such as the one made Jesse Silverberg (Wyss Institute for Biologically Inspired Engineering) and Nan Yang (Laboratory for the Design and Intelligent Control of Advanced Mechatronical Systems).
The potential of metamaterials
Metamaterials have tremendous potential and properties: while they can be amazing on paper, they pose a problem by the lack of practicality in theory and practice alike. Designing a metamaterial on paper to answer certain properties is out there, yet it doesn’t guarantee the material can have a physical existence. The other way is tricky as well: starting with a feasible metamaterial and trying to optimize it to achieve a desired feature is not guaranteed either.
Lego, bricks and colours
Silverberg and Yang found a clever way to bring more of their features to the physical reality. Inspired by their children’s colourful lego pieces, they thought of the blocks of metamaterials as bricks and of the colours as properties. Assembling them will then result in a material with unique properties that makes up for each block’s shortcoming with another block’s strength.
The catch is the assembly type: will it be like a child’s piling method? Placing bricks upon bricks? Or something more complex? The answer was in origami. One can’t deny that origami shapes are more resilient than the sheet of paper they are made of. In fact, studies have previously proved how folded sheets that follow origami patterns provide unexpectedly greater properties than the raw material. Therefore, Yang and Silverberg thought of following origami patterns to assemble their blocks and insure good properties. After all, origami patterns have been around for centuries and proved their resilience. All that is left is to find the folding design patterns which best suit the desired properties.
Back to basics
In the end, it boils down to geometry and design of the structures. There are other considerations as well, such as manufacturing processes and the type of scale at which metamateriel design can occur. Yang and Silverberg demonstrated that using these techniques also decouples the mechanical functions of the modular parts of the metamaterials. This allows control over the parameters to influence and optimize the cost and the time. In fact, many biomaterials and biomaterial manufactured parts can profit from this type of design, such as tissue engineering scaffolds.