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Jiang X, Molokeev MS, Dong L, Dong Z, Wang N, Kang L, Li X, Li Y, Tian C, Peng S, Li W, Lin Z. Anomalous mechanical materials squeezing three-dimensional volume compressibility into one dimension. Nat Commun 2020; 11:5593. [PMID: 33154363 PMCID: PMC7644688 DOI: 10.1038/s41467-020-19219-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 09/29/2020] [Indexed: 11/30/2022] Open
Abstract
Anomalous mechanical materials, with counterintuitive stress-strain responding behaviors, have emerged as novel type of functional materials with highly enhanced performances. Here we demonstrate that the materials with coexisting negative, zero and positive linear compressibilities can squeeze three-dimensional volume compressibility into one dimension, and provide a general and effective way to precisely stabilize the transmission processes under high pressure. We propose a "corrugated-graphite-like" structural model and discover lithium metaborate (LiBO2) to be the first material with such a mechanical behavior. The capability to keep the flux density stability under pressure in LiBO2 is at least two orders higher than that in conventional materials. Our study opens a way to the design and search of ultrastable transmission materials under extreme conditions.
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Affiliation(s)
- Xingxing Jiang
- Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, P.R. China
| | - Maxim S Molokeev
- Laboratory of Crystal Physics, Kirensky Institute of Physics, SB RAS, Krasnoyarsk, 660036, Russia
- Department of Physics, Far Eastern State Transport University, Khabarovsk, 680021, Russia
- Siberian Federal University, Krasnoyarsk, 660041, Russia
| | - Liyuan Dong
- Wuhan National Laboratory for Optoelectronics and School of Physics, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Zhichao Dong
- Laboratory of Space Astronomy and Technology, National Astronomical Observatories, Chinese Academy of Sciences, Beijing, 100101, China
| | - Naizheng Wang
- Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Lei Kang
- Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, P.R. China
| | - Xiaodong Li
- Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100049, China
| | - Yanchun Li
- Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100049, China
| | - Chuan Tian
- Institute of Deep-sea Science and Engineering, Chinese Academy of Sciences, Sanya, 572000, China
| | - Shiliu Peng
- Institute of Mechanics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Wei Li
- School of Materials Science and Engineering; TKL of Metal and Molecule-Based Material Chemistry, Nankai University, Tianjin, 300350, China
| | - Zheshuai Lin
- Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, P.R. China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
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2
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Wang Y, Liu Q, Zhang J, Hong T, Sun W, Tang L, Arnold E, Suo Z, Hong W, Ren Z, Guo CF. Giant Poisson's Effect for Wrinkle-Free Stretchable Transparent Electrodes. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2019; 31:e1902955. [PMID: 31268581 DOI: 10.1002/adma.201902955] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Revised: 06/10/2019] [Indexed: 06/09/2023]
Abstract
The next generation of flexible electronics will require highly stretchable and transparent electrodes, many of which consist of a relatively stiff metal network (or carbon materials) and an underlying soft substrate. Typically, such a stiff-soft bilayer suffers from wrinkling or folding when subjected to strains, causing high surface roughness and seriously deteriorated optical transparency. In this work, a network with a giant effective Poisson's ratio on a soft substrate is found to be under biaxial tension upon deformation, and thus does not wrinkle or fold, but maintains smooth surfaces and high transparency. Soft tactile sensors employing such network electrodes exhibit high transparency and low fatigue over many stretching cycles. Such a giant Poisson's ratio has the same effect in other systems. This work offers a new understanding of surface instabilities and a general strategy to prevent them not only in flexible electronics, but also in other materials and mechanical structures that require flat surfaces.
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Affiliation(s)
- Yan Wang
- Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
- Centers for Mechanical Engineering Research and Education at MIT and SUSTech, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
| | - Qihan Liu
- School of Engineering and Applied Sciences, Kavli Institute for Nanobio Science and Technology, Harvard University, Cambridge, MA, 02138, USA
| | - Jianming Zhang
- Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
- Centers for Mechanical Engineering Research and Education at MIT and SUSTech, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
| | - Tianzeng Hong
- Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
| | - Wenting Sun
- Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
| | - Lu Tang
- Department of Physics and TcSUH, University of Houston, TX, 77204, USA
| | - Eric Arnold
- Burdette Keeland Jr. Design Exploration Center, College of Architecture and Design, University of Houston, TX, 77204, USA
| | - Zhigang Suo
- School of Engineering and Applied Sciences, Kavli Institute for Nanobio Science and Technology, Harvard University, Cambridge, MA, 02138, USA
| | - Wei Hong
- Department of Mechanics and Aerospace Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
| | - Zhifeng Ren
- Department of Physics and TcSUH, University of Houston, TX, 77204, USA
| | - Chuan Fei Guo
- Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
- Centers for Mechanical Engineering Research and Education at MIT and SUSTech, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
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3
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Jin E, Lee IS, Kim D, Lee H, Jang WD, Lah MS, Min SK, Choe W. Metal-organic framework based on hinged cube tessellation as transformable mechanical metamaterial. SCIENCE ADVANCES 2019; 5:eaav4119. [PMID: 31114799 PMCID: PMC6527257 DOI: 10.1126/sciadv.aav4119] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Accepted: 03/26/2019] [Indexed: 06/09/2023]
Abstract
Mechanical metamaterials exhibit unusual properties, such as negative Poisson's ratio, which are difficult to achieve in conventional materials. Rational design of mechanical metamaterials at the microscale is becoming popular partly because of the advance in three-dimensional printing technologies. However, incorporating movable building blocks inside solids, thereby enabling us to manipulate mechanical movement at the molecular scale, has been a difficult task. Here, we report a metal-organic framework, self-assembled from a porphyrin linker and a new type of Zn-based secondary building unit, serving as a joint in a hinged cube tessellation. Detailed structural analysis and theoretical calculation show that this material is a mechanical metamaterial exhibiting auxetic behavior. This work demonstrates that the topology of the framework and flexible hinges inside the structure are intimately related to the mechanical properties of the material, providing a guideline for the rational design of mechanically responsive metal-organic frameworks.
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Affiliation(s)
- Eunji Jin
- Department of Chemistry, Ulsan National Institute of Science and Technology, 50 UNIST, Ulsan 44919, Republic of Korea
| | - In Seong Lee
- Department of Chemistry, Ulsan National Institute of Science and Technology, 50 UNIST, Ulsan 44919, Republic of Korea
| | - Dongwook Kim
- Department of Chemistry, Ulsan National Institute of Science and Technology, 50 UNIST, Ulsan 44919, Republic of Korea
| | - Hosoowi Lee
- Department of Chemistry, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, Republic of Korea
| | - Woo-Dong Jang
- Department of Chemistry, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, Republic of Korea
| | - Myung Soo Lah
- Department of Chemistry, Ulsan National Institute of Science and Technology, 50 UNIST, Ulsan 44919, Republic of Korea
| | - Seung Kyu Min
- Department of Chemistry, Ulsan National Institute of Science and Technology, 50 UNIST, Ulsan 44919, Republic of Korea
| | - Wonyoung Choe
- Department of Chemistry, Ulsan National Institute of Science and Technology, 50 UNIST, Ulsan 44919, Republic of Korea
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4
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Yoo Y, Kim YJ, Kim DN, Lee JH. A near-zero Poisson's ratio of Si with ordered nanopores. Phys Chem Chem Phys 2016; 18:21949-53. [DOI: 10.1039/c6cp03248f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Significant reduction in the Poisson's ratio is predicted for Si with cylindrical nanopores through first-principles DFT calculations.
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Affiliation(s)
- Yongmin Yoo
- School of Materials Science and Engineering
- Gwangju Institute of Science and Technology
- Republic of Korea
| | - Young-Joo Kim
- Department of Mechanical and Aerospace Engineering
- Seoul National University
- Republic of Korea
| | - Do-Nyun Kim
- Department of Mechanical and Aerospace Engineering
- Seoul National University
- Republic of Korea
| | - Joo-Hyoung Lee
- School of Materials Science and Engineering
- Gwangju Institute of Science and Technology
- Republic of Korea
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5
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Ho DT, Park SD, Kwon SY, Park K, Kim SY. Negative Poisson’s ratios in metal nanoplates. Nat Commun 2014; 5:3255. [DOI: 10.1038/ncomms4255] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Accepted: 01/15/2014] [Indexed: 11/09/2022] Open
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Zhang W, Soman P, Meggs K, Qu X, Chen S. Tuning the Poisson's Ratio of Biomaterials for Investigating Cellular Response. ADVANCED FUNCTIONAL MATERIALS 2013; 23:10.1002/adfm.201202666. [PMID: 24076754 PMCID: PMC3785557 DOI: 10.1002/adfm.201202666] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Cells sense and respond to mechanical forces, regardless of whether the source is from a normal tissue matrix, an adjacent cell or a synthetic substrate. In recent years, cell response to surface rigidity has been extensively studied by modulating the elastic modulus of poly(ethylene glycol) (PEG)-based hydrogels. In the context of biomaterials, Poisson's ratio, another fundamental material property parameter has not been explored, primarily because of challenges involved in tuning the Poisson's ratio in biological scaffolds. Two-photon polymerization is used to fabricate suspended web structures that exhibit positive and negative Poisson's ratio (NPR), based on analytical models. NPR webs demonstrate biaxial expansion/compression behavior, as one or multiple cells apply local forces and move the structures. Unusual cell division on NPR structures is also demonstrated. This methodology can be used to tune the Poisson's ratio of several photocurable biomaterials and could have potential implications in the field of mechanobiology.
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7
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Mitschke H, Robins V, Mecke K, Schröder-Turk GE. Finite auxetic deformations of plane tessellations. Proc Math Phys Eng Sci 2013. [DOI: 10.1098/rspa.2012.0465] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
We systematically analyse the mechanical deformation behaviour, in particular Poisson's ratio, of floppy bar-and-joint frameworks based on periodic tessellations of the plane. For frameworks with more than one deformation mode, crystallographic symmetry constraints or minimization of an angular vertex energy functional are used to lift this ambiguity. Our analysis allows for systematic searches for auxetic mechanisms in archives of tessellations; applied to the class of one- or two-uniform tessellations by regular or star polygons, we find two auxetic structures of hexagonal symmetry and demonstrate that several other tessellations become auxetic when retaining symmetries during the deformation, in some cases with large negative Poisson ratios
ν
<−1 for a specific lattice direction. We often find a transition to negative Poisson ratios at finite deformations for several tessellations, even if the undeformed tessellation is infinitesimally non-auxetic. Our numerical scheme is based on a solution of the quadratic equations enforcing constant edge lengths by a Newton method, with periodicity enforced by boundary conditions.
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Affiliation(s)
- Holger Mitschke
- Theoretische Physik, Friedrich-Alexander Universität Erlangen-Nürnberg, Staudtstrasse 7B, 91058 Erlangen, Germany
| | - Vanessa Robins
- Applied Maths, Research School of Physical Sciences and Engineering, The Australian National University, Canberra, 0200 Australian Capital Territory, Australia
| | - Klaus Mecke
- Theoretische Physik, Friedrich-Alexander Universität Erlangen-Nürnberg, Staudtstrasse 7B, 91058 Erlangen, Germany
| | - Gerd E. Schröder-Turk
- Theoretische Physik, Friedrich-Alexander Universität Erlangen-Nürnberg, Staudtstrasse 7B, 91058 Erlangen, Germany
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8
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Spatial tuning of negative and positive Poisson's ratio in a multi-layer scaffold. Acta Biomater 2012; 8:2587-94. [PMID: 22465577 DOI: 10.1016/j.actbio.2012.03.035] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2011] [Revised: 03/11/2012] [Accepted: 03/21/2012] [Indexed: 11/21/2022]
Abstract
While elastic modulus is tunable in tissue engineering scaffolds, it is substantially more challenging to tune the Poisson's ratio of scaffolds. In certain biological applications, scaffolds with a tunable Poisson's ratio may be more suitable for emulating the behavior of native tissue mechanics. Here, we design and fabricate a scaffold, which exhibits simultaneous negative and positive Poisson's ratio behavior. Custom-made digital micro-mirror device stereolithography was used to fabricate single- and multiple-layer scaffolds using polyethylene glycol-based biomaterial. These scaffolds are composed of pore structures having special geometries, and deformation mechanisms, which can be tuned to exhibit both negative Poisson's ratio (NPR) and positive Poisson's ratio (PPR) behavior in a side-to-side or top-to-bottom configuration. Strain measurement results demonstrate that analytical deformation models and simulations accurately predict the Poisson's ratios of both the NPR and PPR regions. This hybrid Poisson's ratio property can be imparted to any photocurable material, and potentially be applicable in a variety of biomedical applications.
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9
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Greaves GN, Greer AL, Lakes RS, Rouxel T. Poisson's ratio and modern materials. NATURE MATERIALS 2011; 10:823-837. [PMID: 22020006 DOI: 10.1038/nmat3134] [Citation(s) in RCA: 521] [Impact Index Per Article: 40.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
In comparing a material's resistance to distort under mechanical load rather than to alter in volume, Poisson's ratio offers the fundamental metric by which to compare the performance of any material when strained elastically. The numerical limits are set by ½ and -1, between which all stable isotropic materials are found. With new experiments, computational methods and routes to materials synthesis, we assess what Poisson's ratio means in the contemporary understanding of the mechanical characteristics of modern materials. Central to these recent advances, we emphasize the significance of relationships outside the elastic limit between Poisson's ratio and densification, connectivity, ductility and the toughness of solids; and their association with the dynamic properties of the liquids from which they were condensed and into which they melt.
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Affiliation(s)
- G N Greaves
- Department of Materials Science and Metallurgy, University of Cambridge, Cambridge, UK.
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10
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Fozdar DY, Soman P, Lee JW, Han LH, Chen S. Three-Dimensional Polymer Constructs Exhibiting a Tunable Negative Poisson's Ratio. ADVANCED FUNCTIONAL MATERIALS 2011; 21:2712-2720. [PMID: 21841943 PMCID: PMC3155506 DOI: 10.1002/adfm.201002022] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Young's modulus and Poisson's ratio of a porous polymeric construct (scaffold) quantitatively describe how it supports and transmits external stresses to its surroundings. While Young's modulus is always non-negative and highly tunable in magnitude, Poisson's ratio can, indeed, take on negative values despite the fact that it is non-negative for virtually every naturally occurring and artificial material. In some applications, a construct having a tunable negative Poisson's ratio (an auxetic construct) may be more suitable for supporting the external forces imposed upon it by its environment. Here, three-dimensional polyethylene glycol scaffolds with tunable negative Poisson's ratios are fabricated. Digital micromirror device projection printing (DMD-PP) is used to print single-layer constructs composed of cellular structures (pores) with special geometries, arrangements, and deformation mechanisms. The presence of the unit-cellular structures tunes the magnitude and polarity (positive or negative) of Poisson's ratio. Multilayer constructs are fabricated with DMD-PP by stacking the single-layer constructs with alternating layers of vertical connecting posts. The Poisson's ratios of the single- and multilayer constructs are determined from strain experiments, which show (1) that the Poisson's ratios of the constructs are accurately predicted by analytical deformation models and (2) that no slipping occurrs between layers in the multilayer constructs and the addition of new layers does not affect Poisson's ratio.
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Affiliation(s)
- David Y. Fozdar
- Department of Mechanical Engineering, The University of Texas at Austin, 204 E. Dean Keaton St., ETC 1.210A, Austin, TX 78712, USA
| | - Pranav Soman
- Department of NanoEngineering, University of California, San Diego, 9500 Gilman Drive, Atkinson Hall, MC-0448, La Jolla, CA 92093, USA
| | - Jin Woo Lee
- Department of NanoEngineering, University of California, San Diego, 9500 Gilman Drive, Atkinson Hall, MC-0448, La Jolla, CA 92093, USA
| | - Li-Hsin Han
- Department of Orthopaedic Surgery, Stanford University School of Medicine, 300 Pasteur Dr., Edwards R132, Stanford, CA 94305, USA
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Mitschke H, Schwerdtfeger J, Schury F, Stingl M, Körner C, Singer RF, Robins V, Mecke K, Schröder-Turk GE. Finding auxetic frameworks in periodic tessellations. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2011; 23:2669-2674. [PMID: 21823262 DOI: 10.1002/adma.201100268] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
It appears that most models for micro-structured materials with auxetic deformations were found by clever intuition, possibly combined with optimization tools, rather than by systematic searches of existing structure archives. Here we review our recent approach of finding micro-structured materials with auxetic mechanisms within the vast repositories of planar tessellations. This approach has produced two previously unknown auxetic mechanisms, which have Poisson's ratio νss=-1 when realized as a skeletal structure of stiff incompressible struts pivoting freely at common vertices. One of these, baptized Triangle-Square Wheels, has been produced as a linear-elastic cellular structure from Ti-6Al-4V alloy by selective electron beam melting. Its linear-elastic properties were measured by tensile experiments and yield an effective Poisson's ratio νLE≈-0.75, also in agreement with finite element modeling. The similarity between the Poisson's ratios νSS of the skeletal structure and νLE of the linear-elastic cellular structure emphasizes the fundamental role of geometry for deformation behavior, regardless of the mechanical details of the system. The approach of exploiting structure archives as candidate geometries for auxetic materials also applies to spatial networks and tessellations and can aid the quest for inherently three-dimensional auxetic mechanisms.
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Abstract
Most materials become narrower in cross section when stretched, but some materials, such as foams, have the counterintuitive property of becoming fatter when stretched (they have a negative Poisson's ratio). In this Perspective, Lakes discusses how his unusual property may arise in isotropic and anisotropic materials. He highlights the study by Baughman et al., who show that anisotropic materials with a negative Poisson's ratio in one direction can be incompressible, i.e., without an overall change in volume upon stretching. This behavior is predicted for materials with very high density, such as neutron star crusts, or very low density, such as ion plasmas, and the validity of the prediction is demonstrated with experimental data for ion plasmas.
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13
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Multiscale Hybrid Materials with Negative Poisson’s Ratio. ACTA ACUST UNITED AC 2009. [DOI: 10.1007/978-1-4020-9033-2_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Pour N, Itzhaki L, Hoz B, Altus E, Basch H, Hoz S. Auxetics at the Molecular Level: A Negative Poisson's Ratio in Molecular Rods. Angew Chem Int Ed Engl 2006; 45:5981-3. [PMID: 16906614 DOI: 10.1002/anie.200601764] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Nir Pour
- Department of Chemistry, Bar-Ilan University, Ramat-Gan 52900, Israel
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15
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Pour N, Itzhaki L, Hoz B, Altus E, Basch H, Hoz S. Auxetics at the Molecular Level: A Negative Poisson's Ratio in Molecular Rods. Angew Chem Int Ed Engl 2006. [DOI: 10.1002/ange.200601764] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Peura M, Grotkopp I, Lemke H, Vikkula A, Laine J, Müller M, Serimaa R. Negative Poisson Ratio of Crystalline Cellulose in Kraft Cooked Norway Spruce. Biomacromolecules 2006; 7:1521-8. [PMID: 16677034 DOI: 10.1021/bm050722o] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The tensile properties of kraft cooked Norway spruce were studied by tensile testing with in situ X-ray diffraction (XRD). Samples were of earlywood, cooked for varying times. The total lignin content of the samples was between 21.7% and 9.3%. Tensile tests with XRD were performed on wet samples, without XRD on dry samples. The tensile strength, the modulus of elasticity (MOE), and the elongation at fracture/yield were determined. X-ray diffraction was used to determine the microfibril angle (MFA) and the deformation of crystalline cellulose by monitoring the reflections 200 and 004. The (X-ray) Poisson ratio of crystalline cellulose was calculated, both before and after the yield point. The tensile strength and the MOE of the wet samples were significantly lower than in the dry samples. The tensile properties of dry samples were similar to dry earlywood samples of untreated Norway spruce. The MFA only showed notable changes due to strain when it was initially large, when a diminishing effect was observed. The Poisson ratio of crystalline cellulose was negative. The average values ranged between -0.26 and -1.17 before the yield point and between -0.86 and -1.05 after the yield point.
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Affiliation(s)
- Marko Peura
- Department of Physical Sciences, Division of X-ray Physics, P.O. Box 64, FI-00014 University of Helsinki, Finland
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BRUNO MARIA, MORESI MAURO. INTERRELATIONSHIP BETWEEN THE TRANSIENT FUNCTIONS OF BOLOGNA USING FRIEDRICH AND HEYMANN THEORY. J Texture Stud 2005. [DOI: 10.1111/j.1745-4603.2005.00001.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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18
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Wojciechowski KW. Non-chiral, molecular model of negative Poisson ratio in two dimensions. ACTA ACUST UNITED AC 2003. [DOI: 10.1088/0305-4470/36/47/005] [Citation(s) in RCA: 164] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Wojciechowski KW, Tretiakov KV, Kowalik M. Elastic properties of dense solid phases of hard cyclic pentamers and heptamers in two dimensions. PHYSICAL REVIEW E 2003; 67:036121. [PMID: 12689146 DOI: 10.1103/physreve.67.036121] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2002] [Indexed: 11/07/2022]
Abstract
Systems of model planar, nonconvex, hard-body "molecules" of fivefold and sevenfold symmetry axes are studied by constant pressure Monte Carlo simulations with variable shape of the periodic box. The molecules, referred to as pentamers (heptamers), are composed of five (seven) identical hard disks "atoms" with centers forming regular pentagons (heptagons) of sides equal to the disk diameter. The elastic compliances of defect-free solid phases are computed by analysis of strain fluctuations and the reference (equilibrium) state is determined within the same run in which the elastic properties are computed. Results obtained by using pseudorandom number generators based on the idea proposed by Holian and co-workers [Holian et al., Phys. Rev. E 50, 1607 (1994)] are in good agreement with the results generated by DRAND48. It is shown that singular behavior of the elastic constants near close packing is in agreement with the free volume approximation; the coefficients of the leading singularities are estimated. The simulations prove that the highest density structures of heptamers (in which the molecules cannot rotate) are auxetic, i.e., show negative Poisson ratios.
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Affiliation(s)
- K W Wojciechowski
- Institute of Molecular Physics, Polish Academy of Sciences, Smoluchowskiego 17, 60-179 Poznań, Poland.
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20
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Alderson A, Evans KE. Molecular origin of auxetic behavior in tetrahedral framework silicates. PHYSICAL REVIEW LETTERS 2002; 89:225503. [PMID: 12485081 DOI: 10.1103/physrevlett.89.225503] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2000] [Indexed: 05/24/2023]
Abstract
Recent analytical models for the Poisson's ratios (nu(ij)) of tetrahedral frameworks are applied to alpha-cristobalite and alpha-quartz for the first time. Rotation and dilation of the SiO4 tetrahedral subunits are considered. Each mechanism leads to negative nu(31) values, whereas negative and positive values are possible when they act concurrently. The concurrent model is in excellent agreement with experiment and explains the dichotomy between negative and positive nu(31) values in alpha-cristobalite and alpha-quartz, respectively. The predicted strain-dependent trends confirm those from molecular modeling.
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Affiliation(s)
- Andrew Alderson
- Centre for Materials Research and Innovation, Bolton Institute, Deane Road, United Kingdom.
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Schachar RA, Bax AJ. Mechanism of human accommodation as analyzed by nonlinear finite element analysis. COMPREHENSIVE THERAPY 2002; 27:122-32. [PMID: 11430259 DOI: 10.1007/s12019-996-0006-5] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Results of nonlinear finite element analysis support the Schachar theory of accommodation and demonstrate that the long-held Helmholtz theory of accommodation is impossible.
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23
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Schachar RA, Bax AJ. Mechanism of human accommodation as analyzed by nonlinear finite element analysis. ACTA ACUST UNITED AC 2001. [DOI: 10.1007/s12009-001-0002-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Miller MA, Reinhardt WP. Efficient free energy calculations by variationally optimized metric scaling: Concepts and applications to the volume dependence of cluster free energies and to solid–solid phase transitions. J Chem Phys 2000. [DOI: 10.1063/1.1313537] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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