scholarly journals Conical Kresling origami and its applications to curvature and energy programming

2022 ◽  
Vol 478 (2257) ◽  
Author(s):  
Lu Lu ◽  
Xiangxin Dang ◽  
Fan Feng ◽  
Pengyu Lv ◽  
Huiling Duan
Keyword(s):  
Inverse Design ◽  
Free Form ◽  
Smart Devices ◽  
Energy Landscapes ◽  
Stable States ◽  
Shape Morphing ◽  
Mechanical Metamaterials ◽  
Unit Cells ◽  
New Perspective ◽  
Coupling Deformation

Kresling origami has recently been widely used to design mechanical metamaterials, soft robots and smart devices, benefiting from its bistability and compression-twist coupling deformation. However, previous studies mostly focus on the traditional parallelogram Kresling patterns which can only be folded to cylindrical configurations. In this paper, we generalize the Kresling patterns by introducing free-form quadrilateral unit cells, leading to diverse conical folded configurations. The conical Kresling origami is modelled with a truss system, by which the stable states and energy landscapes are derived analytically. We find that the generalization preserves the bistable nature of parallelogram Kresling patterns, while enabling an enlarged design space of geometric parameters for structural and mechanical applications. To demonstrate this, we develop inverse design frameworks to employ conical Kresling origami to approximate arbitrary target surfaces of revolution and achieve prescribed energy landscapes. Various numerical examples obtained from our framework are presented, which agree well with the paper models and the finite-element simulations. We envision that the proposed conical Kresling pattern and inverse design framework can provide a new perspective for applications in deployable structures, shape-morphing devices, multi-modal robots and multistable metamaterials.

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

2021 ◽  
Vol 7 (9) ◽  
pp. eabf1966
Author(s):  
Hang Zhang ◽  
Jun Wu ◽  
Daining Fang ◽  
Yihui Zhang
Keyword(s):  
Structural Diversity ◽  
Cell Number ◽  
Structural Elements ◽  
Ternary Logic ◽  
Stable States ◽  
One Dimensional ◽  
Logic Operation ◽  
Artificial Materials ◽  
Mechanical Metamaterials ◽  
Unit Cells

Multistable mechanical metamaterials are artificial materials whose microarchitectures offer more than two different stable configurations. Existing multistable mechanical metamaterials mainly rely on origami/kirigami-inspired designs, snap-through instability, and microstructured soft mechanisms, with mostly bistable fundamental unit cells. Scalable, tristable structural elements that can be built up to form mechanical metamaterials with an extremely large number of programmable stable configurations remains illusive. Here, we harness the elastic tensile/compressive asymmetry of kirigami microstructures to design a class of scalable X-shaped tristable structures. Using these structure as building block elements, hierarchical mechanical metamaterials with one-dimensional (1D) cylindrical geometries, 2D square lattices, and 3D cubic/octahedral lattices are designed and demonstrated, with capabilities of torsional multistability or independent controlled multidirectional multistability. The number of stable states increases exponentially with the cell number of mechanical metamaterials. The versatile multistability and structural diversity allow demonstrative applications in mechanical ternary logic operators and amplitude modulators with unusual functionalities.

scholarly journals Divergent Design of Mechanical Metamaterials Clan Deducted from Arc-serpentine Curve

2021 ◽  
Author(s):  
Shengli Mi ◽  
Hongyi Yao ◽  
Xiaoyu Zhao ◽  
Wei Sun
Keyword(s):  
Thick Plate ◽  
Three Dimensional ◽  
Spatial Arrangement ◽  
Design Strategies ◽  
Shape Morphing ◽  
Mechanical Metamaterials ◽  
Unit Cells ◽  
Combinatorial Principles ◽  
Composite Curve ◽  
Typical Design

Abstract The exotic properties of mechanical metamaterials are determined by their unit-cells' structure and spatial arrangement, in analogy with the atoms of conventional materials. Companioned with the mechanism of structural or cellular materials1–5, the ancient wisdom of origami6–11 and kirigami12–16 and the involvement of multiphysics interaction2,17,18 enrich the programable mechanical behaviors of metamaterials, including shape-morphing8,12,14,16,19, compliance4,5,8,17,20, texture2,18,21, and topology11,18,22−25. However, typical design strategies are mainly convergent, which transfers various structures into one family of metamaterials that are relatively incompatible with the others and do not fully bring combinatorial principles3,10,26 into play. Here, we report a divergent strategy that designs a clan of mechanical metamaterials with diverse properties derived from a symmetric curve consisting of serpentines and arcs. We derived this composite curve into planar and cubic unit-cells and modularized them by attaching magnetics. Moreover, stacking each of them yields two- and three-dimensional auxetic metamaterials, respectively. Assembling with both modules, we achieved three thick plate-like metamaterials separately with flexibility, in-plane buckling, and foldability. Furthermore, we demonstrated that the hybrid of paradox properties is possible by combining two of the above assembles. We anticipate that this divergent strategy paves the path of building a hierarchical library of diverse combinable mechanical metamaterials and making conventional convergent strategies more efficient to various requests. Main

scholarly journals Harnessing the anisotropic multistability of stacked-origami mechanical metamaterials for effective modulus programming

2018 ◽  
Vol 29 (14) ◽  
pp. 2933-2945 ◽  
Author(s):  
Sattam Sengupta ◽  
Suyi Li
Keyword(s):  
Adaptive Systems ◽  
Three Dimensional ◽  
Unit Cell ◽  
Effective Modulus ◽  
Stable States ◽  
Mechanical Metamaterials ◽  
Principal Axes ◽  
Unit Cells ◽  
Multiple Unit ◽  
Parametric Analyses

This study examines a three-dimensional, anisotropic multistability of a mechanical meta material based on a stacked Miura-ori architecture, and investigates how such a unique stability property can impart stiffness and effective modulus programming functions. The unit cell of this metamaterial can be bistable due to the nonlinear relationship between rigid-folding and crease material bending. Such bistability possesses an unorthodox property: the arrangement of elastically stable and unstable equilibria are different along different principal axes of the unit cell, so that along certain axes the unit cell exhibits two force–deformation relationships concurrently within the same range of deformation. Therefore, one can achieve a notable stiffness adaptation via switching between the two stable states. As multiple unit cells are assembled into a metamaterial, the stiffness adaptation can be aggregated into an on-demand modulus programming capability. That is, via strategically switching different unit cells between stable states, one can control the overall effective modulus. This research examines the underlying principles of anisotropic multistability, experimentally validates the feasibility of stiffness adaptation, and conducts parametric analyses to reveal the correlations between the effective modulus programming and Miura-ori designs. The results can advance many adaptive systems such as morphing structures and soft robotics.

Shape-Morphing Mechanical Metamaterials

2021 ◽  
pp. 103146
Author(s):  
Caigui Jiang ◽  
Florian Rist ◽  
Hui Wang ◽  
Johannes Wallner ◽  
Helmut Pottmann
Keyword(s):  
Shape Morphing ◽  
Mechanical Metamaterials

A Sequential Two-Step Design Framework for Deformable Mechanical Metamaterials

2020 ◽  
Author(s):  
Sree Kalyan Patiballa ◽  
Girish Krishnan
Keyword(s):  
Shape Change ◽  
Building Blocks ◽  
Load Flow ◽  
Stretchable Electronics ◽  
Design Framework ◽  
Shape Morphing ◽  
Mechanical Metamaterials ◽  
Global Deformation ◽  
Deformation Patterns

Abstract Deformable metamaterials are materials that are made up of several repeating elastic building blocks whose geometries can be tailored to obtain a specified global shape change or stiffness behavior. They are deemed useful in soft robotics, shape morphing mechanisms, stretchable electronics, wearable devices, and devices that adapt according to their environment. This paper presents a two-step sequential design framework for the synthesis of deformable mechanical metamaterials where (a) topology optimization is used to map global deformation requirement to local elasticity matrix, followed by (b) a selection of building block microstructure geometry from a database and refining it to match the elasticity requirement. The first step is accomplished through a unique parameterization scheme that enables the classification of the planar orthotropic elasticity matrix into four distinct classes. The second step uses a kinetostatic framework known as load flow visualization to populate candidate microstructure geometries within these four classes. Finally, the framework is validated for the design of a cantilever beam with a specified lateral stiffness requirement and the design of planar sheets that exhibit sinusoidal deformation patterns.

scholarly journals Non-reciprocal robotic metamaterials

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Martin Brandenbourger ◽  
Xander Locsin ◽  
Edan Lerner ◽  
Corentin Coulais
Keyword(s):  
Skin Effect ◽  
Mechanical Energy ◽  
Standing Waves ◽  
Control Loops ◽  
Active Metamaterials ◽  
Mechanical Metamaterials ◽  
Wide Range ◽  
Propagating Waves ◽  
Mechanical Analogue ◽  
Unit Cells

Abstract Non-reciprocal transmission of motion is potentially highly beneficial to a wide range of applications, ranging from wave guiding to shock and vibration damping and energy harvesting. To date, large levels of non-reciprocity have been realized using broken spatial or temporal symmetries, yet mostly in the vicinity of resonances, bandgaps or using nonlinearities, thereby non-reciprocal transmission remains limited to narrow ranges of frequencies or input magnitudes and sensitive to attenuation. Here, we create a robotic mechanical metamaterials wherein we use local control loops to break reciprocity at the level of the interactions between the unit cells. We show theoretically and experimentally that first-of-their-kind spatially asymmetric standing waves at all frequencies and unidirectionally amplified propagating waves emerge. These findings realize the mechanical analogue of the non-Hermitian skin effect. They significantly advance the field of active metamaterials for non hermitian physics and open avenues to channel mechanical energy in unprecedented ways.

An Antagonistic Flexural Unit Cell for Design of Shape Morphing Structures

Aerospace ◽  
2004 ◽  
Author(s):  
Aarash Y. N. Sofla ◽  
Dana M. Elzey ◽  
Haydn N. G. Wadley
Keyword(s):  
Shape Memory ◽  
Unit Cell ◽  
External Energy ◽  
Full Characterization ◽  
Shape Morphing ◽  
Cyclic Operation ◽  
Unit Cells ◽  
External Forces ◽  
Reversed Cyclic

An antagonistic flexural unit cell (AFC) concept for the design and fabrication of novel 2-D and 3-D lightweight shape morphing structures is introduced. A fully reversible flexural shape changing cell utilizing opposing one-way shape memory alloy (SMA) actuators is shown to require no spring-like bias elements. The SMA actuating elements are arranged such that the actuation (contraction) of one of them stretches the other one in the cell, preparing it to be actuated later to reverse a flexural displacement. This antagonistic operation allows fully reversed cyclic operation. The focus of this paper is an assessment of performance at the single cell level. The cell logically provides four possible configurations in different stages of its cycle. Two of them are of particular interest because they provide two different fixed shapes for the cell that can be maintained without the continuous supply of external energy. The final deformations of the cell and equilibrium stresses in the SMA elements depend on the amount of stored shape memory strain in each element, external forces and cell geometry. A model is developed, which allows a full characterization of the AFC. The model is used to study NiTi SMA-based AFCs and the results are therefore directly applicable to the design of shape morphing structures using such unit cells.

scholarly journals Non-Auxetic Mechanical Metamaterials

Materials ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 635 ◽  
Author(s):  
Christa de Jonge ◽  
Helena Kolken ◽  
Amir Zadpoor
Keyword(s):  
Mechanical Properties ◽  
Yield Stress ◽  
Fatigue Behavior ◽  
Analytical Data ◽  
Three Dimensional ◽  
Mechanical Metamaterials ◽  
Macro Scale ◽  
Unit Cells ◽  
Poisson's Ratios ◽  
Poisson’S Ratios

The concept of “mechanical metamaterials” has become increasingly popular, since their macro-scale characteristics can be designed to exhibit unusual combinations of mechanical properties on the micro-scale. The advances in additive manufacturing (AM, three-dimensional printing) techniques have boosted the fabrication of these mechanical metamaterials by facilitating a precise control over their micro-architecture. Although mechanical metamaterials with negative Poisson’s ratios (i.e., auxetic metamaterials) have received much attention before and have been reviewed multiple times, no comparable review exists for architected materials with positive Poisson’s ratios. Therefore, this review will focus on the topology-property relationships of non-auxetic mechanical metamaterials in general and five topological designs in particular. These include the designs based on the diamond, cube, truncated cube, rhombic dodecahedron, and the truncated cuboctahedron unit cells. We reviewed the mechanical properties and fatigue behavior of these architected materials, while considering the effects of other factors such as those of the AM process. In addition, we systematically analyzed the experimental, computational, and analytical data and solutions available in the literature for the titanium alloy Ti-6Al-4V. Compression dominated lattices, such as the (truncated) cube, showed the highest mechanical properties. All of the proposed unit cells showed a normalized fatigue strength below that of solid titanium (i.e., 40% of the yield stress), in the range of 12–36% of their yield stress. The unit cells discussed in this review could potentially be applied in bone-mimicking porous structures.

scholarly journals Design and Analysis of a Photonic Crystal Based Planar Antenna for THz Applications

Electronics ◽  
2021 ◽  
Vol 10 (16) ◽  
pp. 1941
Author(s):  
Inzamam Ahmad ◽  
Sadiq Ullah ◽  
Shakir Ullah ◽  
Usman Habib ◽  
Sarosh Ahmad ◽  
...  
Keyword(s):  
Communication Systems ◽  
High Speed ◽  
Low Cost ◽  
High Gain ◽  
Propagation Loss ◽  
Smart Devices ◽  
Frequency Range ◽  
Low Profile ◽  
Unit Cells ◽  
Thz Applications

Modern advancements in wearable smart devices and ultra-high-speed terahertz (THz) communication systems require low cost, low profile, and highly efficient antenna design with high directionality to address the propagation loss at the THz range. For this purpose, a novel shape, high gain antenna for THz frequency range applications is presented in this work. The proposed antenna is based on a photonic bandgap (PBG)-based crystal polyimide substrate which gives optimum performance in terms of gain (9.45 dB), directivity (9.99 dBi), and highly satisfactory VSWR (<1) at 0.63 THz. The performance of the antenna is studied on PBGs of different geometrical configurations and the results are compared with the antenna based on the homogeneous polyimide-based substrate. The effects of variations in the dimensions of the PBG unit cells are also studied to achieve a −10 dB bandwidth of 28.97 GHz (0.616 to 0.64 THz).

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