A Stair‐Building Strategy for Tailoring Mechanical Behavior of Re‐Customizable Metamaterials

Abstract

Re‐customizable mechanical behavior is critical for versatile materials with tunable functions and applications, but inverse design for varying targets is often hindered by complex coupling between structural topologies and mechanics. In this work, a novel “stair‐building” strategy for customizing as well as re‐customizing target mechanical behavior for mechanical metamaterials is proposed. Similar to building a stair with bricks, customizing or re‐customizing a target stress–strain (force–displacement) curve for the material can be realized by stacking the brick‐like loading curves of bistable units visually. The mechanical feasibility of the “stair‐building” strategy is firstly physically realized in a type of array‐structured multistable mechanical metamaterial and then carefully verified by theoretical mechanics analysis. Accordingly, three specific simple design schemes are further proposed for implementation. The “stair‐building” strategy is proved to be rapid, effective, and accurate for mechanical behavior customization by both experiments and finite element simulations. Moreover, re‐customization for diverse mechanical behaviors in a wide range can be realized by the same piece of metamaterial. This design strategy provides a novel approach for tailoring metamaterials with re‐customizable target mechanical behaviors and applies to a variety of bistable units.

3D Flexible Frequency Selective Surface with Stable Electromagnetic Transmission Properties

“…Therefore, it is vital to explore the deformation law of flexible 3D FSS subjected to biaxial stretch strains, which was investigated by mechanical simulation software ABAQUS (seen in Mechanics Simulation section for details) and biaxial tensile experimental device (seen in Mechanics Measurement section for details), respectively. In the FEA model, the elastic modulus of PI, Cu, and ecoflex are 2.5 GPa, 119 GPa, and 0.06 MPa, and their corresponding Poisson's ratios are 0.34, 0.34, and 0.49, respectively [23] . Due to the huge difference in thickness between the Cu/PI lamination and the ecoflex layer, the FEA model was built with the S4R mesh in the Cu/PI lamination and the C3D8R mesh in the ecoflex considering large deformation in order to improve the computational efficiency and accuracy.…”

“…Recent research advances on flexible electronics and 3D assemblies, [23][24][25] fabricated by releasing prestrain in the elastic substrate and thus buckling metal unit cell locally bonded on it, have attracted widespread interest among researchers because of this unique advantage of maintaining the small strain in the internal metal without local plastic deformation when subjected to high stretch strains. As a result, the 3D assemblies can be Frequency selective surfaces (FSS) that can be tightly laminated to complex nondevelopable surfaces have a wide range of applications in many engineering areas.…”

Electrothermally Driven Nucleation Energy Control of Defective Carbon and Nickel–Cobalt Oxide-Based Electrodes

“…Hybridizing multielement metal/metal oxides with carbon-based supports can overcome the intrinsic limitations of single-material electrodes. − In particular, rationally designed interfaces of their hybrids have enhanced electrochemical properties such as improved energy storage capabilities, catalytic reactions, and long-term stabilities. − While multielement metal/metal oxides provide high energy storage capacity and efficient charge transfer through redox reactions, electrosorption, and intercalation processes at interfaces, their low stabilities and conductivities must be compensated to prevent electrode degradation. − Due to their low thermal–chemical reactivities and high mechanical stabilities, supports made from carbon nanotubes, graphene, or carbon fibers (CFs) can provide additional conductive pathways for charge transport and mitigate electrode degradation during charge–discharge cycles; however, to realize high energy and reaction density, their relatively low capacitances and redox compatibilities must be addressed. , Therefore, to create a synergistic effect between the multielement metal/metal oxides and the carbon-based supports, optimal combinations and interface design are important.…”

Digital synthesis of free-form multimaterial structures for realization of arbitrary programmed mechanical responses

“…Advanced functionalities are achieved based on various mechanical responses (force–displacement or stress–strain relations) with distinct function-oriented features. Considerable advances in response programming have been made through varying structural geometry (i.e., feature sizes, cellular patterns, hole shapes, structural topology, deformation states) ( 2 , 4 , 6 , 8 , 10 , 11 , 13 – 22 ), assembly sequence ( 5 , 7 , 23 – 25 ), and external confinement ( 26 ), which produce responses including stiffening, softening, multistable, buckling, and auxetic behaviors. Most of the established metamaterials are based on heuristically developed patterns or usage of a single constituent material.…”

“…To extend the dimension of programmability, the created structures are used as building blocks and assembled into heterogeneous material architectures that exhibit highly complex yet navigable responses. Different from many assembled metamaterials, which use the same or similar building blocks ( 5 , 7 , 24 , 25 , 32 ), the constructed architectures herein are composed of diverse synthesized structures with distinct geometries and behaviors. Such heteroassembly effectively enlarges the design space and enables the realization of many extreme responses that would otherwise be unattainable.…”