Auxetic properties of a tangram-inspired metamaterial

Lim, Teik‐Cheng

doi:10.1088/2631-8695/acc1c5

Cited by 10 publications

(5 citation statements)

References 88 publications

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“…[29] A comprehensive survey of these works has been reviewed by Grima-Cornish et al [30] . Shortly thereafter, auxetic systems based on combined quadrilaterals and triangles [31][32][33][34] as well as rotating and nonrotating quadrilaterals [35] were introduced. More recent investigations involve rotating parallelograms and triangles [36] as well as rotating trapeziums and triangles.…”

Section: Introductionmentioning

confidence: 99%

Auxetic System Based on Rotating Hexagons and Triangles

Lim

2024

Physica Status Solidi (b)

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An auxetic metamaterial that exhibits isotropic in‐plane deformation is introduced herein in the form of rotating rigid units, consisting of regular hexagons and equilateral triangles, that are connected at their vertices. By inspection, the in‐plane Poisson's ratio is at a constant value of ν = −1. The size descriptor of this metamaterial can be expressed as a function of rotating unit sizes and their internal angle by means of geometrical construction. By energy method, the effective in‐plane Young's modulus of this metamaterial has been established and shown to be governed by the rotational stiffness at the connecting hinges in addition to the relative sizes of the rotating units and their internal angle. Results indicate that the in‐plane Young's modulus is linearly proportional to the rotational stiffness at the connecting hinges and inversely proportional to the rigid unit size. In addition, the Young's modulus is governed by the ratio of the hexagon‐to‐triangle size for small internal angle, and rapidly approaches extreme value as the internal angle approaches right angle. The characteristics of the proposed metamaterial would allow its use as a sieve that not only controls the filtering of particles by size but also by the aspect ratio of rod‐like particles.

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Section: Introductionmentioning

confidence: 99%

Auxetic System Based on Rotating Hexagons and Triangles

Lim

2024

Physica Status Solidi (b)

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“…The corpus of knowledge on auxetics has expanded significantly in the last decades [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22], particularly since the manufacture of the first soft auxetic material-a foam-which could be easily stretched and compressed by hand [23]. These novel materials were attributed several enhanced characteristics which are not normally manifested by their conventional counter-parts [24][25][26][27][28][29][30][31], which made them particularly appealing to the sports community [32][33][34][35][36][37][38].…”

Section: Introductionmentioning

confidence: 99%

On the effect of the poisson’s ratio on samples subjected to shearing

Attard,

Caruana-Gauci,

Cerasola

et al. 2023

Eng. Res. Express

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The effect of shearing on finite-sized auxetic and non-auxetic samples was examined through finite element simulations. It was shown that when shear was applied in a manner representative of a common shear-testing setup, which is not dissimilar to the situation encountered in sports applications, auxetics manifested very different characteristics compared to their non-auxetic counterparts; with very pronounced edge effects. These included extensive lateral expansion of the samples and the formation of non-insignificant concave creases on their exposed lateral faces. It was shown that these creases became even more pronounced when the samples were subjected to combined shear and compressive loads and need to be taken into consideration when assessing the suitability, or otherwise, of auxetics for practical applications where shear loading may be present to a certain extent.

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“…These rotating units are mostly in the form of quadrilaterals [13,14,[53][54][55][56] or triangles [57,58]. In an extension from rotating squares and rectangles of different sizes [59], there have been recent works on two kinds of metamaterials consisting of combined rotating quadrilaterals and triangles units that give auxetic properties [60,61] as well as negative thermal expansion with sign-programmable Poisson's ratio [62,63].…”

Section: Introductionmentioning

confidence: 99%

Metamaterials with Poisson's ratio discontinuity by means of fragmentation–reconstitution rotating units

Lim

2023

Proc. R. Soc. A.

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This paper presents for the first time two types of metamaterials based on the fragmentation–reconstitution of rotating units in order to produce Poisson's ratio discontinuity at the original state. For both metamaterials, each rotating unit takes the form of a rhombus that comprises eight sub-units. During on-axis stretching, each rhombus fragments into eight rotating sub-units. When the prescribed strain is reversed, these eight sub-units reconstitute back into a single rotating rhombus such that they rotate as a rigid body. Using geometrical construction, the incremental Poisson's ratio was established at the original state. In the case of large deformation, the finite Poisson's ratio was formulated in conjunction with the maximum allowable rotations for full stretching along both axes and for full compression. The family of on-axes Poisson's ratio versus rotational angles for various shape descriptors displays a fork-shaped distribution with discontinuity at the original state. Two major distinguishing factors of these metamaterials—property discontinuity at the original state with constant and variable Poisson's ratio under compression and tension, respectively—allow them to function in ways that cannot be fully performed by conventional materials or even by auxetic materials and metamaterials.

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Auxetic properties of a tangram-inspired metamaterial

Cited by 10 publications

References 88 publications

Auxetic System Based on Rotating Hexagons and Triangles

Auxetic System Based on Rotating Hexagons and Triangles

On the effect of the poisson’s ratio on samples subjected to shearing

Metamaterials with Poisson's ratio discontinuity by means of fragmentation–reconstitution rotating units

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