Micro‐/Nanostructured Mechanical Metamaterials

Abstract

Mechanical properties of materials have long been one of the most fundamental and studied areas of materials science for a myriad of applications. Recently, mechanical metamaterials have been shown to possess extraordinary effective properties, such as negative dynamic modulus and/or density, phononic bandgaps, superior thermoelectric properties, and high specific energy absorption. To obtain such materials on appropriate length scales to enable novel mechanical devices, it is often necessary to effectively design and fabricate micro-/nano- structured materials. In this Review, various aspects of the micro-/nano-structured materials as mechanical metamaterials, potential tools for their multidimensional fabrication, and selected methods for their structural and performance characterization are described, as well as some prospects for the future developments in this exciting and emerging field.

Nanoarchitectured materials composed of fullerene-like spheroids and disordered graphene layers with tunable mechanical properties

“…Because of the skeletal nature of the architecture, metamaterials generally have the advantage of being extremely lightweight 8 . The length scales of these periodical building blocks (similar to unit cells in crystalline materials) are typically on the order of tens of microns and above, thereby precise fabrication techniques (for example, lithography) are commonly needed 7 , limiting their assemblies to relatively large scales (centimetres and above). Therefore, it is more practical and cost-effective to produce statistically averaged fine-scaled building blocks, for example, as shown by some carbon and polymer foams [3][4][5]9 .…”

“…Mechanical metamaterials are a special type of architectured material composed of tailored functional building blocks periodically arranged and connected to yield unusual mechanical properties, such as negative Poisson's ratio, negative compressibility and negative incremental stiffness, all of which are not common in natural materials [5][6][7] . The metamaterials gain their exceptional properties not only from their composition but also from their exactingly designed architectures with special shape, geometry, size, orientation and arrangement.…”

Expansive Periodic Mechanisms

“…Auxetic capabilities in periodic materials and metamaterials are of considerable interest, Lakes (1987), Evans et al (1991), Greaves et al (2011), Lee et al (2012). Thus, expansive structures as considered in this paper may serve, in particular, for auxetic design.…”

Surface Patterning of Functional Ceramics: A Materials Design

“…While conventional applications take advantage of the size, shape, and the high specific area of the surface nanostructures, carefully designed periodic features are now being used to fabricate metamaterials with novel properties (Shalaev, 2007;Lee et al, 2012). Surface patterns can be created on solid substrates either by "top-down" approaches or by "bottom-up" methods.…”