Deformation mechanism of innovative 3D chiral metamaterials

Wu, Wenwang; Qi, Dexing; Liao, Hua; Qian, Guian; Geng, Luchao; Niu, Yinghao; Liang, Jun

doi:10.1038/s41598-018-30737-7

Cited by 64 publications

(35 citation statements)

References 49 publications

(35 reference statements)

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“…By tuning the direction of the interlayer connections, materials with two positive and one negative Poisson ratios have been first analytically predicted and successively confirmed through numerical simulations and experimental test on medium-size samples printed with the stereolithography technology [33]. Other different topologies of 3D chiral materials have been proposed and their deformation mechanisms have been experimentally studied through tensile and compression tests on selected laser sintered samples [34].…”

Section: Introductionmentioning

confidence: 94%

A novel layered topology of auxetic materials based on the tetrachiral honeycomb microstructure

et al. 2019

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Microstructured honeycomb materials may exhibit exotic, extreme and tailorable mechanical properties, suited for innovative technological applications in a variety of modern engineering fields. The paper is focused on analysing the directional auxeticity of tetrachiral materials, through analytical, numerical and experimental methods. Theoretical predictions about the global elastic properties have been successfully validated by performing tensile laboratory tests on tetrachiral samples, realized with high precision 3D printing technologies. Inspired by the kinematic behaviour of the tetrachiral material, a newly-design bi-layered topology, referred to as bi-tetrachiral material, has been theoretically conceived and mechanically modelled. The novel topology virtuously exploits the mutual collaboration between two tetrachiral layers with opposite chiralities. The bi-tetrachiral material has been verified to outperform the tetrachiral material in terms of global Young modulus and, as major achievement, to exhibit a remarkable auxetic behaviour. Specifically, experimental results, confirmed by parametric analytical and computational analyses, have highlighted the effective possibility to attain strongly negative Poisson ratios, identified as a peculiar global elastic property of the novel bi-layered topology.

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Section: Introductionmentioning

confidence: 94%

A novel layered topology of auxetic materials based on the tetrachiral honeycomb microstructure

et al. 2019

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“…Methods 3D printing and samples preparation. 15 samples of hinged-3D assembled unit cells were prepared to demonstrate the giant Poisson's ratio of our developed metamaterial ( Fig. 2(a)).…”

Section: Discussionmentioning

confidence: 99%

Hinged-3D metamaterials with giant and strain-independent Poisson’s ratios

Shaat

Wagih

2020

Sci Rep

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Current designs of artificial metamaterials with giant Poisson's ratios proposed microlattices that secrete the transverse displacement nonlinearly varies with the longitudinal displacement, and thePoisson's ratio depends on the applied strain (i.e., tailorable Poisson's ratio). Whereas metamaterials with tailorable Poisson's ratios would find many important applications, the design of a metamaterial with a giant Poisson's ratio that is constant over all the material deformation range has been a major challenge. Here, we develop a new class of bimaterial-3D-metamaterials with giant and strainindependent Poisson's ratios (i.e., Poisson's ratio is constant over the entire deformation range). The unit cell is 3D assembled of hinged-struts. Specially designed spherical hinges were utilized to give constant Poisson's ratios. This new class of metamaterials has been demonstrated by means of experimental and numerical mechanics. 15 material samples were 3D printed by Stereolithography (SLA) and tested. We revealed a robust anisotropy dependence of the Poisson's ratio. A giant negative Poisson's ratio of −16 was obtained utilizing a highly anisotropic unit cell of dissimilar materials and stiffnesses. Materials with giant and strain-independent Poisson's ratios provide a new class of artificial metamaterials, which would be used to optimize the performance of many existing devices, e.g., strain amplifiers and gauges.Artificial metamaterials are multiscale materials with exceptional macroscopic behaviors arising from the design of their microstructures beyond those of conventional materials found in nature 1,2 . The microstructure of a metamaterial can be tailored and optimized to promote the activation of nontraditional microscopic phenomena 2,3 . When these phenomena are activated, a metamaterial exhibits extraordinary behaviors beyond those observed in conventional materials. For example, membrane-type acoustic metamaterials with weak elastic moduli can give low-frequency oscillation patterns, which would produce an equivalent negative mass density of sound attenuation in specific frequency ranges 4-6 . In addition, metamaterials of cubic symmetric 3D-unit cells with special topologies that promote microstructural buckling can give auxetic behaviors; i.e., an auxetic metamaterial is a material with a negative Poisson's ratio 7 . Furthermore, metamaterials with crosslinked-3D unit cells can be fabricated to give an equivalent negative static compressibility 8 . By tailoring the mechanism of interaction between the inclusions and the matrix, composite metamaterials with equivalent negative mass densities, moduli, and/or Poisson's ratios can be obtained 2,9-12 . A unit cell of hexagonal sub-units has been proposed to give a mechanical metamaterial with negative stiffness and negative Poisson's ratio 13 . Other approaches that have been used for making metamaterials with negative Poisson's ratios depended on hierarchical 14 , chiral 15,16 , kirigami 17,18 , and lattice 19,20 unit cells. Recently, mechanical metamaterials ...

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“…As a special type of auxetic materials, chiral metastructures cannot be superimposed onto its mirror body by simple rigid rotations and spatial translations. Normally, chiral structures are architected with nodes and ligaments in 2D or 3D spaces, and has been proposed for various types of industrial applications, such as: morphing airfoil, expanding antenna, auxetic stent, etc . Systematical theoretical, simulation and experimental investigations on the mechanical properties of chiral metastructures are performed in the past decades.…”

Section: Introductionmentioning

confidence: 99%

“…Systematical theoretical, simulation and experimental investigations on the mechanical properties of chiral metastructures are performed in the past decades. Meanwhile, several types of advanced manufacturing techniques are employed for fabricating chiral industrial components, such as: resin transfer molding (RTM) process for composite chiral airfoil, selective laser melting (SLM) metal additive manufacturing of gradient chiral metastructures for impact energy absorption . However, industrial manufacturing defects are inevitably for chiral components and structures, inducing strong or weak local defects into the structures, which may have remarkable impacts on the mechanical integrity of chiral structures.…”

Section: Introductionmentioning

confidence: 99%

Effects of Disordered Circular Nodes Dispersion and Missing Ligaments on the Mechanical Properties of Chiral Structures

Niu

Liang

et al. 2019

Physica Status Solidi (b)

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Auxetics with negative Poisson's ratio (NPR) can expand dimensions along the direction perpendicular to the tensile direction, such as rigid rotation, reentrant and chiral structures, etc. The mechanical performances of chiral metastructures are closely related to internal defects and interactions between defects. In this paper, two types of irregular chiral structures with Gaussian dispersion of circular node positions and missing ligaments are designed, namely: antitetrachiral metastructure and tetrachiral hybrid metastructure. These two types of chiral metastructures are characterized by node radius, ligament thickness, ligament length, the circular node center dispersion range, and missing ligament percentages. Effects of random node distribution range and cell wall missing percentage on the elastic modulus and Poisson's ratio of chiral metastructures are investigated through experimental tests and finite element (FE) simulation systematically. Through dimensionless analysis, it is found that ligament thickness has remarkable influence on the negative Poisson's ratio. Effect of missing ligament on the mechanical properties of the structure is greater than effect of random node center dispersion. With the increase of ligament missing percentage, the resultant modulus of chiral metastructures decreases, and the corresponding NPR increases.

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Deformation mechanism of innovative 3D chiral metamaterials

Cited by 64 publications

References 49 publications

A novel layered topology of auxetic materials based on the tetrachiral honeycomb microstructure

A novel layered topology of auxetic materials based on the tetrachiral honeycomb microstructure

Hinged-3D metamaterials with giant and strain-independent Poisson’s ratios

Effects of Disordered Circular Nodes Dispersion and Missing Ligaments on the Mechanical Properties of Chiral Structures

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