Auxetics Explained

Auxetics are typical structures of the representative mechanical meta-materials. Mechanical meta-materials are structures whose mechanical properties are artificially derived from sophisticated structures and refer to unique structures that do not take place in nature. Herein, the basic concept of meta (meta means beyond in Greek) implies something that goes beyond naturally occurring substances. Generally, materials have a positive Poisson's ratio. Unlike general materials, Auxetics are structures or materials that have a negative Poisson's ratio. In terms of general materials, it is noted that while elongating along the x axis, the length in the y axis is decreased. Interestingly, in terms of the auxetic structure, while it expands along the x axis, y axis also expands simultaneously. In other words, elongation occurs in both directions, causing a rapid increase in volume.[1] [2]

ν = -ε(trans) / ε(axial)where, ε(trans) is the transverse strain and ε(axial) is the axial strain.

Auxetics can be single molecules, crystals, or a particular structure of macroscopic matter.Expansion structures of Auxetics are being attempted in a variety of fields. Typical studies are being conducted on impact protection, medical devices, textiles, and sound vibration control. In terms of impact protection, Auxetic materials are appropriate for use in protective equipment such as body armor, helmets, and knee pads. This is because it is able to absorb energy more effectively than traditional materials. It is also actively studied in devices such as medical stents or implants. This is because its unique properties can improve the performance and longevity of stents or implants. Auxetic fabrics can be used to create comfortable and flexible clothing that conventional materials cannot embody, as well as technical fabrics for applications such as aerospace and sports equipment. Finally, as for the sound and vibration control field, Auxetic materials can be used to create acoustic meta-materials for controlling sound and vibration in diverse applications.

Meanwhile, research using auxetic structures is also ongoing in the microscopic world. Unlike the general belief that auxeticity is rarely shown in crystalline solids, most of the cubic elemental metals show when they are stretched along the [110] direction. As an example, both compliance coefficients (i.e. s11 and s12) of Zn single crystals have the same sign. As a result, as for θ = 0, ν12 = −s12/s11 around equals −0.073 < 0, so the Poisson’s ratio of mono-crystalline Zn in its underlying plane is negative. For these metals, the auxeticity allows for the existence, in the orthogonal lateral direction, of positive Poisson’s ratios until the stability limit of 2 for cubic crystals. Such metals were expected to allow for electrodes that exponentially increase the response of piezoelectric sensors.[3]

History

The term auxetic derives from the Greek word (Greek, Modern (1453-);: αὐξητικός) which means 'that which tends to increase' and has its root in the word (Greek, Modern (1453-);: αὔξησις), meaning 'increase' (noun). This terminology was coined by Professor Ken Evans of the University of Exeter.[4] [5] One of the first artificially produced auxetic materials, the RFS structure (diamond-fold structure), was invented in 1978 by the Berlin researcher K. Pietsch. Although he did not use the term auxetics, he describes for the first time the underlying lever mechanism and its non-linear mechanical reaction so he is therefore considered the inventor of the auxetic net.The earliest published example of a material with negative Poisson's constant is due to A. G. Kolpakov in 1985, "Determination of the average characteristics of elastic frameworks"; the next synthetic auxetic material was described in Science in 1987, entitled "Foam structures with a Negative Poisson's Ratio" by R.S. Lakes from the University of Wisconsin Madison. The use of the word auxetic to refer to this property probably began in 1991.[6] Recently, cells were shown to display a biological version of auxeticity under certain conditions. [7]

Designs of composites with inverted hexagonal periodicity cell (auxetic hexagon), possessing negative Poisson ratios, were published in 1985.[8]

For these reasons, gradually, many researchers have become interested in the unique properties of Auxetics. This phenomenon is visible in the number of publications (Scopus search engine), as shown in the following figure. In 1991, there was only one publication. However, in 2016, around 165 publications were released, so the number of publications has exploded - a 165-fold increase in just 25 years - clearly showing that the topic of Auxetics is drawing considerable attention.[9] However, although Auxetics are promising structures and have a lot of potential in science and engineering, their widespread application in multiple fields is still a challenge. Therefore, additional research related to Auxetics is required for widespread applications.

Properties

Typically, auxetic materials have low density, which is what allows the hinge-like areas of the auxetic microstructures to flex.[10]

At the macroscale, auxetic behaviour can be illustrated with an inelastic string wound around an elastic cord. When the ends of the structure are pulled apart, the inelastic string straightens while the elastic cord stretches and winds around it, increasing the structure's effective volume. Auxetic behaviour at the macroscale can also be employed for the development of products with enhanced characteristics such as footwear based on the auxetic rotating triangles structures developed by Grima and Evans[11] [12] [13] and prosthetic feet with human-like toe joint properties.[14]

Auxeticity is also common in biological materials. The origin of auxeticity is very different in biological materials than the materials discussed above. One of the example is nuclei of mouse embryonic stem cells in transition state. A model has been developed by Tripathi et. al [15] to explain it.

Examples

Examples of auxetic materials include:

See also

External links

Notes and References

  1. Mir, Mariam, et al. "Review of mechanics and applications of auxetic structures." Advances in Materials Science and Engineering 2014 (2014).
  2. Lee, Young-Joo, et al. "Auxetic elastomers: Mechanically programmable meta-elastomers with an unusual Poisson’s ratio overcome the gauge limit of a capacitive type strain sensor." Extreme Mechanics Letters 31 (2019): 100516.
  3. Yang, Wei, et al. "Review on auxetic materials." Journal of materials science 39 (2004): 3269-3279.
  4. .
  5. .
  6. .
  7. .
  8. Kolpakov . A.G. . 1985 . Determination of the average characteristics of elastic frameworks . Journal of Applied Mathematics and Mechanics . 49 . 6. 739–745 . 10.1016/0021-8928(85)90011-5. 1985JApMM..49..739K .
  9. Ren, Xin, et al. "Auxetic metamaterials and structures: a review." Smart materials and structures 27.2 (2018): 023001.
  10. https://www.newscientist.com/article/mg15420854.200-a-stretch-of-the-imagination.html A stretch of the imagination – 7 June 1997 – New Scientist Space
  11. Grima. JN. Evans. KE. 2000. Auxetic behavior from rotating squares. Journal of Materials Science Letters. 19. 17. 1563–1565. 10.1023/A:1006781224002. 138455050.
  12. Grima. JN. Evans. KE. 2006. Auxetic behavior from rotating triangles. Journal of Materials Science. 41. 10. 3193–3196. 10.1007/s10853-006-6339-8. 2006JMatS..41.3193G . 137547536.
  13. Web site: Nike Free 2016 product press release.
  14. Hong . Woolim . Kumar . Namita Anil . Patrick . Shawanee . Um . Hui-Jin . Kim . Heon-Su . Kim . Hak-Sung . Hur . Pilwon . 2022 . Empirical Validation of an Auxetic Structured Foot With the Powered Transfemoral Prosthesis . IEEE Robotics and Automation Letters . 7 . 4 . 11228–11235 . 10.1109/LRA.2022.3194673 . 251170703 . 2377-3766.
  15. Tripathi . Kamal . Menon . Gautam I. . 2019-10-28 . Chromatin Compaction, Auxeticity, and the Epigenetic Landscape of Stem Cells . Physical Review X . 9 . 4 . 041020 . 10.1103/PhysRevX.9.041020. 209958957 . free .
  16. Li . Yan . Zeng . Changchun . On the successful fabrication of auxetic polyurethane foams: Materials requirement, processing strategy and conversion mechanism . Polymer . 2016 . 10.1016/j.polymer.2016.01.076. 87 . 98–107.
  17. Li . Yan . Zeng . Changchun . Room‐Temperature, Near‐Instantaneous Fabrication of Auxetic Materials with Constant Poisson's Ratio over Large Deformation . Advanced Materials . 2016 . 10.1002/adma.201505650. 26861805 . 28 . 14 . 2822–2826 . 5260896 .
  18. Yeganeh-Haeri. Amir. Weidner. Donald J.. Parise. John B.. 31 July 1992. Elasticity of α-Cristobalite: A Silicon Dioxide with a Negative Poisson's Ratio. Science. en. 257. 5070. 650–652. 10.1126/science.257.5070.650. 0036-8075. 17740733. 1992Sci...257..650Y . 137416819.
  19. Goldstein. R.V.. Gorodtsov. V.A.. Lisovenko. D.S.. 2013. Classification of cubic auxetics. Physica Status Solidi B. en. 250. 10. 2038–2043. 10.1002/pssb.201384233 . 117802510 .
  20. Gorodtsov. V.A.. Lisovenko. D.S.. 2019. Extreme values of Young's modulus and Poisson's ratio of hexagonal crystals. Mechanics of Materials. en. 134. 1–8. 10.1016/j.mechmat.2019.03.017 . 140493258 .
  21. Grima-Cornish . JN . Vella-Zarb . L . Grima . JN . Negative Linear Compressibility and Auxeticity in Boron Arsenate . Annalen der Physik. 2020 . 532 . 5 . 1900550 . 10.1002/andp.201900550 . 2020AnP...53200550G . 216414513 .
  22. Grima . J. N. . Winczewski . S. . Mizzi . L. . Grech . M. C. . Cauchi . R. . Gatt . R. . Attard . D. . Wojciechowski . K.W. . Rybicki . J. . Tailoring Graphene to Achieve Negative Poisson's Ratio Properties . 10.1002/adma.201404106 . 25504060 . Advanced Materials . 2014 . 27 . 8 . 1455–1459. 19738771 .
  23. Grima. Joseph N.. Grech. Michael C.. Grima‐Cornish. James N.. Gatt. Ruben. Attard. Daphne. 2018. Giant Auxetic Behaviour in Engineered Graphene. Annalen der Physik. en. 530. 6. 1700330. 10.1002/andp.201700330. 1521-3889. 2018AnP...53000330G. 125889091 .
  24. Rysaeva. L.Kh.. Baimova. J.A.. Lisovenko. D.S.. Gorodtsov. V.A.. Dmitriev. S.V.. 2019. Elastic properties of fullerites and diamond-like phases. Physica Status Solidi B. en. 256. 1. 1800049. 10.1002/pssb.201800049 . 2019PSSBR.25600049R.
  25. Goldstein. R.V.. Gorodtsov. V.A.. Lisovenko. D.S.. Volkov. M.A.. 2014. Negative Poisson's ratio for cubic crystals and nano/microtubes. Physical Mesomechanics. en. 17. 2. 97–115. 10.1134/S1029959914020027 . 137267947.
  26. Bryukhanov. I.A.. Gorodtsov. V.A.. Lisovenko. D.S.. 2019. Chiral Fe nanotubes with both negative Poisson's ratio and Poynting's effect. Atomistic simulation. Journal of Physics: Condensed Matter. en. 31. 47. 475304. 10.1088/1361-648X/ab3a04 . 31398716. 2019JPCM...31U5304B. 199519252 .
  27. Gatt R, Vella Wood M, Gatt A, Zarb F, Formosa C, Azzopardi KM, Casha A, Agius TP, Schembri-Wismayer P, Attard L, Chockalingam N, Grima JN . Negative Poisson's ratios in tendons: An unexpected mechanical response . Acta Biomater. . 2015 . 10.1016/j.actbio.2015.06.018 . 26102335 . 24 . 201–208.
  28. .
  29. Book: Mark, Schenk. Folded Shell Structures, PhD Thesis. University of Cambridge, Clare College. 2011.
  30. 10.1038/srep05979. 25099402. 4124469. Origami based Mechanical Metamaterials. Scientific Reports. 4. 5979. 2015. Lv. Cheng. Krishnaraju. Deepakshyam. Konjevod. Goran. Yu. Hongyu. Jiang. Hanqing.
  31. Unraveling metamaterial properties in zigzag-base folded sheets. Science Advances. 2015. 2375-2548. e1500224. 1. 8. 10.1126/sciadv.1500224. Maryam. Eidini. Glaucio H.. Paulino. 1502.05977 . 2015SciA....1E0224E. 26601253. 4643767.
  32. Eidini. Maryam. Zigzag-base folded sheet cellular mechanical metamaterials. Extreme Mechanics Letters. 6. 96–102. 10.1016/j.eml.2015.12.006. 2016. 1509.08104. 118424595.
  33. Tailored 3D Mechanical Metamaterials Made by Dip-in Direct-Laser-Writing Optical Lithography. Tiemo Bückmann. etal. 10.1002/adma.201200584. 24. 20. Advanced Materials. 2710–2714. 22495906. May 2012. 205244958 .
  34. Grima‐Cornish. James N.. Grima. Joseph N.. Evans. Kenneth E.. 2017. On the Structural and Mechanical Properties of Poly(Phenylacetylene) Truss-Like Hexagonal Hierarchical Nanonetworks. Physica Status Solidi B. en. 254. 12. 1700190. 10.1002/pssb.201700190. 1521-3951. 2017PSSBR.25400190G. 10871/31485. 126184802 . free.
  35. Cabras. Luigi. Brun. Michele. 2014. Auxetic two-dimensional lattices with Poisson's ratio arbitrarily close to −1. Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences. en. 470. 2172. 20140538. 10.1098/rspa.2014.0538. 1407.5679. 2014RSPSA.47040538C. 1364-5021. free.
  36. Carta. Giorgio. Brun. Michele. Baldi. Antonio. 2016. Design of a porous material with isotropic negative Poisson's ratio. Mechanics of Materials. en. 97. 67–75. 10.1016/j.mechmat.2016.02.012.
  37. Cabras. Luigi. Brun. Michele. 2016. A class of auxetic three-dimensional lattices. Journal of the Mechanics and Physics of Solids. en. 91. 56–72. 10.1016/j.jmps.2016.02.010. 1506.04919. 2016JMPSo..91...56C. 85547530.
  38. Kaminakis. N. Stavroulakis. G. 2012. Topology optimization for compliant mechanisms, using evolutionary-hybrid algorithms and application to the design of auxetic materials. Composites Part B Engineering. 43. 6. 2655–2668. 10.1016/j.compositesb.2012.03.018.
  39. Stetsenko . M . 2015 . Determining the elastic constants of hydrocarbons of heavy oil products using molecular dynamics simulation approach . Journal of Petroleum Science and Engineering . 126 . 124–130 . 10.1016/j.petrol.2014.12.021 . free .

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