3D Pixel Mechanical Metamaterials

Abstract

Metamaterials have unprecedented properties that facilitate the development of advanced devices and machines. However, their interconnected building structures limit their applications, especially in the fields that require large deformation, rich programmability and efficient shape‐reconfigurability. To break this limit and exploit more potentialities of metamaterials, an innovative material design strategy is proposed, named mechanical pixel (MP) array design. Similar to a screen that displays images by adjusting the colors of pixels, the metamaterials can form and reconfigure 3D morphologies by tuning the heights (lengths) of the MPs in the array. The strategy is demonstrated in a multistable metamaterial by experimental tests, theoretical analysis, and numerical simulations. Using this strategy, a large macroscopic shear deformation is obtained, and remarkable enhancements in the mechanical programmability, shape‐reconfigurability and adaptability, and reusable shock‐resistance are exhibited. Moreover, mechanical design and property prediction for the metamaterials are both greatly simplified due to the pixelated design. For a piece of the 3D pixel metamaterial with m n‐unit MPs, the number of programmable displacement–force curves increases from n+1 to 2m∙n+1, and the number of stable morphologies grows from n+1 to at least (n+1)m. This strategy can be used to enhance the merits and further excavate the potential of versatile metamaterials.

4D Printing Auxetic Metamaterials with Tunable, Programmable, and Reconfigurable Mechanical Properties

“…Metamaterials are any engineering materials composed of unique microstructures when arranged in an orderly manner, and can exhibit attractive properties not found in natural materials. [1][2][3][4] The emergence of these metamaterials makes it possible to customize the macroscopic physical properties (i.e., mechanical, acoustic, thermal, electromagnetic, etc.) by designing the topological parameters and arrangement of the microstructures.…”

Hierarchical mechanical metamaterials built with scalable tristable elements for ternary logic operation and amplitude modulation

“…These materials, sometimes termed as "multistable mechanical metamaterials," are designed to offer more than two stable states that can be switched reversibly among each other. This requires an elaborate manipulation of the energy landscape, and several strategies have been reported, including those that rely on origami/kirigami-inspired designs (48)(49)(50)(51)(52)(53)(54), snap-through instability (42,(55)(56)(57)(58)(59), microstructured soft mechanisms (36,43,60), and geometrical frustration (61)(62)(63). For example, the diversity and high foldability of prismatic geometries have been leveraged in the context of origami techniques to develop a class of three-dimensional (3D) multistable metamaterials with periodic arrangements of rigid plates and elastic hinges (49,52,53).…”

“…This paper introduces a class of X-shaped kirigami microstructures as tristable building block elements, which can be extended, following a bottom-up scheme, to achieve hierarchical mechanical metamaterials with an exponentially increased number of stable states. Here, the tristability arises mainly from the elastic tensile/ compressive asymmetry of kirigami microstructures, representing a distinct mechanism from those exploited in previous designs of multistable mechanical metamaterials (36,37,40,42,43,(55)(56)(57)(58)(59)(60)(61). Multimaterial 3D printing technologies enable the fabrication and experimental validation of the programmable multistability in mechanical metamaterials with 1D cylindrical geometries, 2D square lattices, and 3D cubic/octahedral lattices.…”

Biomimetic Meta‐Structured Electro‐Microfluidics

“…Inspired by nature, meta-structured membranes (MSMs) as substrates for fabricating integrated microfluidics and electronics are presented. [11,12] Although there have been some attempts in this field, the high processing cost and complex processing process limit its full application in various fields.Nature provides excellent strategies for the realization of advanced multifunctional materials. The final MSMs constitute with integrated ordered micro-and nanostructures and exhibit spontaneous liquid transfer, fluorescence enhancement, and intimate skin contact.…”

“…In the past decade, there have been increasing interests in metamaterials (structures) in scientific communities. [11,12] Although there have been some attempts in this field, the high processing cost and complex processing process limit its full application in various fields. [9,10] Among many forms of metamaterials, highly ordered, micro-nano hybrid structures are beyond most striking styles.…”