Measurement of Poisson’s ratio of the auxetic structure

Yolcu, Dilek Atilla; Baba, Buket Okutan

doi:10.1016/j.measurement.2022.112040

Cited by 13 publications

(7 citation statements)

References 42 publications

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“…In addition, Poisson's ratio, v, compares the strains in the transverse (ε t ) and longitudinal (ε l ) directions under uniaxial stress 24,25 :…”

Section: Experimental Characterizationmentioning

confidence: 99%

“…In addition, Poisson's ratio,

v

, compares the strains in the transverse (

{\varepsilon}_t

) and longitudinal (

{\varepsilon}_l

) directions under uniaxial stress 24,25 :

v=-\frac{\varepsilon_t}{\varepsilon_l}=-\frac{\left(\frac{T-t}{t}\right)}{\left(\frac{L-l}{l}\right)}.

…”

Section: Experimental and Theoretical Proceduresmentioning

confidence: 99%

“…The normal strain (

\varepsilon

) is a unit of measure used to determine the amount of length changes (

L-l

) experienced by a body in the direction of force applied, divided by its initial dimensions (

l

) as follows 24,25 :

\varepsilon =\frac{L-l}{l}.

…”

Section: Experimental and Theoretical Proceduresmentioning

confidence: 99%

See 2 more Smart Citations

An experimental and numerical study on an innovative metastructure for 3D printed thermoplastic polyurethane with auxetic performance

Mojaver,

Azdast,

Hasanzadeh

2024

Polymers for Advanced Techs

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Metamaterials are specifically designed materials that possess unique properties that cannot be found in naturally occurring substances. These remarkable materials have the capability to bring about a significant transformation across a wide range of industries. Auxetic structures are a recent area of research possess a distinctive characteristic known as a negative Poisson's ratio. Unlike conventional materials that contract when stretched, auxetic structures actually expand in two dimensions. In this study, a new auxetic structure was introduced, and thermoplastic polyurethane samples were 3D printed using a fused filament fabrication method. The samples are then subjected to strains ranging from 5% to 50% and Poisson's ratios are measured both experimentally and numerically using finite element method in Ansys software. By comparing the results of the experimental research and simulation, it is evident that applying strains within this range causes the Poisson's ratio of the samples to change from −0.81 to −0.14 and it showed that the newly introduced structure is auxetic. According to the analysis of root mean square error, the hexagonal mesh with a size of 0.7 mm consistently produced the most accurate results, aligning closely with the experimental sample. Given that this is an entirely novel auxetic structure within the category of arrow‐head auxetic structures, there is potential for future research to be conducted in order to further develop and enhance this model.

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“…In addition, Poisson's ratio, v, compares the strains in the transverse (ε t ) and longitudinal (ε l ) directions under uniaxial stress 24,25 :…”

Section: Experimental Characterizationmentioning

confidence: 99%

“…In addition, Poisson's ratio,

v

, compares the strains in the transverse (

{\varepsilon}_t

) and longitudinal (

{\varepsilon}_l

) directions under uniaxial stress 24,25 :

v=-\frac{\varepsilon_t}{\varepsilon_l}=-\frac{\left(\frac{T-t}{t}\right)}{\left(\frac{L-l}{l}\right)}.

…”

Section: Experimental and Theoretical Proceduresmentioning

confidence: 99%

See 1 more Smart Citation

An experimental and numerical study on an innovative metastructure for 3D printed thermoplastic polyurethane with auxetic performance

Mojaver,

Azdast,

Hasanzadeh

2024

Polymers for Advanced Techs

View full text Add to dashboard Cite

show abstract

“…Other similar studies investigated the mechanical properties and deformation mechanisms of "rotating rigid units"-mimicking systems. Amongst others, Wang et al ( 2021) [170] and Atilla Yolcu et al ( 2022) [171] explored such systems designed through the use of regularly and irregularly peanut-shaped perforations (depicted in Figure 4e); Acuna et al [172] simulated rectangular perforations; whilst Mrozek and Strek [173] (Figure 4f) investigated a system of perforations mimicking the rotating squares model [64,[174][175][176]. Afshar et al utilised FEA to investigate non-porous perforated rotating rigid units having a soft inclusion in the perforations.…”

Section: Two Dimensional Systemsmentioning

confidence: 99%

Auxetics and FEA: Modern Materials Driven by Modern Simulation Methods

Galea Mifsud,

Muscat,

Grima-Cornish

et al. 2024

Materials

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Auxetics are materials, metamaterials or structures which expand laterally in at least one cross-sectional plane when uniaxially stretched, that is, have a negative Poisson’s ratio. Over these last decades, these systems have been studied through various methods, including simulations through finite elements analysis (FEA). This simulation tool is playing an increasingly significant role in the study of materials and structures as a result of the availability of more advanced and user-friendly commercially available software and higher computational power at more reachable costs. This review shows how, in the last three decades, FEA proved to be an essential key tool for studying auxetics, their properties, potential uses and applications. It focuses on the use of FEA in recent years for the design and optimisation of auxetic systems, for the simulation of how they behave when subjected to uniaxial stretching or compression, typically with a focus on identifying the deformation mechanism which leads to auxetic behaviour, and/or, for the simulation of their characteristics and behaviour under different circumstances such as impacts.

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“…The fact that performance improvement can be adjusted by changing the location, shape, size and number of perforations provides a great advantage in obtaining the desired result [23]. The structures that can have perforated auxetic unit cells include rotational (semi-) rigid [24], star/diamond-shaped [25], elliptic/peanut-shaped [26,27] and quasi/fully random cuts [28]. These structures have been extensively studied and developed in both 2D and 3D forms, with a shift towards 3D microstructural design to improve the accuracy of predicting auxetic behaviour [29,30].…”

Section: Introductionmentioning

confidence: 99%

Quasi-static crashworthiness behaviour of auxetic tubular structures based on rotating deformation mechanism

Solak,

Orhan

2024

Smart Mater. Struct.

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Auxetic materials have attracted significant interest due to their exceptional mechanical characteristics and distinctive deformation modes. Nevertheless, the practical use of these materials in engineering is constrained by their limited ability to absorb energy. Thus, enhancing the energy absorption (EA) capabilities of auxetic materials is crucial to expand their range of potential applications. In this study, the EA capabilities of auxetic tubular structures with rotating deformation mechanisms are examined, with a specific emphasis on three different perforation shapes: elliptic, peanut, and square, along with their modified versions incorporating stiffeners. The study employs a combination of experimental testing and numerical modelling, utilising ANSYS/LS-DYNA to evaluate various crashworthiness parameters. These parameters include total EA, specific EA, maximum crushing force, and crushing force efficiency, all of which are assessed under quasi-static compression conditions. The research highlights the importance of perforation shape and stiffener incorporation in enhancing crashworthiness. Results show that elliptic perforations exhibit superior EA and stiffened auxetic models outperform conventional ones in terms of crash absorber performance. The presence of stiffeners significantly improves the ability of tubular structures to withstand crushing forces. Furthermore, the study validates the numerical model against experimental findings, demonstrating a high level of agreement in terms of crushing force–displacement, EA, and failure modes. The research provides valuable insights into the design and performance of crashworthy structures and offers potential applications in various fields where impact resistance and EA are critical.

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Measurement of Poisson’s ratio of the auxetic structure

Cited by 13 publications

References 42 publications

An experimental and numerical study on an innovative metastructure for 3D printed thermoplastic polyurethane with auxetic performance

An experimental and numerical study on an innovative metastructure for 3D printed thermoplastic polyurethane with auxetic performance

Auxetics and FEA: Modern Materials Driven by Modern Simulation Methods

Quasi-static crashworthiness behaviour of auxetic tubular structures based on rotating deformation mechanism

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