Boron Arsenate Scaled-Up: An Enhanced Nano-Mimicking Mechanical Metamaterial

Novel mechanical metamaterials inspired by single crystal boron arsenate built at the macroscale using conventional materials are presented and investigated through finite element simulations. It is shown that these mechanical metamaterials can mimic, to some extent, the properties of boron arsenate with the more robust rotating rigid-units mechanism being excellently replicated and even made to operate more efficiently through modifications of the geometry of the mechanical metamaterial. It is also shown that not all mechanisms causing auxeticity at the nanoscale can be upscaled due to the absence of the appropriate interactions at higher length scales. This confirms that already existing materials, which have been adequately characterized and studied, can prove to be a very useful source of information for the design of novel mechanical metamaterials which can exhibit even more auxetic properties than the original material itself.