### Mechanics of Auxetic Materials SpringerLink

In contrast to typical natural materials with a positive Poisson s ratio auxetic materials have a negative Poisson s ratio (NPR) characterized by unilateral shrinkage or expansion against axial compressive or tensile loadings respectively.

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Three-dimensional cellular structures with negative Poisson s ratio and negative compressibility properties. Proceedings of the Royal Society A Mathematical Physical and Engineering Sciences 2012 468 (2146) .

Get Price### Evaluation of Auxetic Polymeric Structures for Use in

Auxetic materials known as materials with negative Poisson s ratio (NPR) have many promising application areas. However there are only few natural and man-made materials such as certain living bone tissues certain rocks and minerals polymeric honeycombs microporous polytetrafluoroethylene (PTFE) foams and carbon-fiber-reinforced epoxy composite laminate panels that possess this property.

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Jul 22 2017 · Poisson s ratio is a measure of the transverse strain relative to longitudinal strain Fung et al.1 Claimed that the Poisson s ratio is bounded between -1 and 0.5 for a linear elastic isotropic material. Cork is the material with zero Poisson s ratio. It was shown in the work of Ting2 that for anisotropic materials Poisson s ratio can be

Get Price### Poisson ratio and bulk lattice constant of (Sr0.25La0.75

Aug 26 2019 · About 30 nm thick (001)-oriented (Sr 0.25 La 0.75)CrO 3 (SLCO) epitaxial thin films were grown by solid-source oxide molecular beam epitaxy on four different single-crystalline cubic or pseudocubic (001)-oriented oxide substrates LaAlO 3 (LaAlO 3) 0.3 (Sr 2 AlTaO 6) 0.7 SrTiO 3 and DyScO 3 which result in lattice mismatch ranging from –2 to 1.7 .All the films are of high-quality

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Fabrication processes of auxetic foam will be discussed throughout as well as their behaviours. Auxetic materials are characterised by the negative Poisson s ratio which in layman s terms means the material dilates in compression and expands under tension. Naturally occurring auxetic materials are rareto find but some examples are rocks

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materials (and structures) the value of Poisson s ratio is posi-tive and reﬂects a tendency to conserve volume. Auxetic materials (ormetamaterials) are those witha negativePoisson s ratio (NPR) i.e. for displaying the unexpected property of lateral expansion when stretched as well as a counterintuitive shrinking when compressed 1–6 .

Get Price### Poisson s Ratio and Auxetic Properties of Natural Rocks

Poisson s Ratio and Auxetic Properties of Natural Rocks Shaocheng Ji 1 LeLi Hem Bahadur Motra2 Frank Wuttke2 Shengsi Sun3 Katsuyoshi Michibayashi4 and Matthew H. Salisbury5 1Département des Génies Civil Géologique et des Mines École Polytechnique de Montréal Montréal Quebec Canada 2Institute of Geosciences Marine and Land Geomechanics and Geotectonics Christian-Albrechts

Get Price### Mechanics of Auxetic Materials SpringerLink

In contrast to typical natural materials with a positive Poisson s ratio auxetic materials have a negative Poisson s ratio (NPR) characterized by unilateral shrinkage or expansion against axial compressive or tensile loadings respectively.

Get Price### Poisson s ratioEngineering ToolBox

With Poisson s ratio for aluminum 0.334the contraction can be calculated as. dr =0.334 (100 10-3 m) (5 10-3 m) / (10 m) = 1.7 10-5 m = 0.017 mm . Poisson s Ratios for Common Materials. For most common materials the Poisson s ratio is in the range 00.5. Typical Poisson s Ratios for some common materials are indicated below.

Get Price### Names of negative Poisson s ratio materials auxetic

Names of these materials Materials with a negative Poisson s ratio (R. S. Lakes Science 1987 1 have been called anti-rubber 2 dilational materials 3 or auxetic materials. These materials are also called auxetics. The name anti-rubber (New York Times 1987) arises from the fact that negative Poisson s ratio materials become fatter in cross section when stretched.

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This section intends to describe auxetic metamaterials from the perspective of their mechanical properties zero or negative Poisson s ratio and negative/positive programmable Poisson s ratio

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Most rocks have ν between about 0.1 and 0.4. Materials with negative Poisson s ratio meaning that they get thinner as they are compressed do exist. They are called auxetic and include the mineral α-cristobalite. Required a table of common (and relevant) values.

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Rock physics aims to characterize rock properties based on the behavior of seismic waves in transverse directions when stretched longitudinally due to their hinge-like molecular structures and are known as auxetic materials. This is roughly true for many rocks. Poisson s ratio can also be expressed in terms of the materials P and S wave

Get Price### Poisson s ratio in orthotropic materials. AIAA Journal

May 17 2012 · Poisson s ratios of auxetic and other technological materials IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control Vol. 57 No. 1 Nonlinear Elastic Deformation Behaviors of Four-Coordinate Flexibly Jointed Structures from Views on Poisson s Ratio

Get Price### Poisson s ratio in orthotropic materials. AIAA Journal

May 17 2012 · Poisson s ratios of auxetic and other technological materials IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control Vol. 57 No. 1 Nonlinear Elastic Deformation Behaviors of Four-Coordinate Flexibly Jointed Structures from Views on Poisson s Ratio

Get Price### Review on auxetic materialsSpringer

May 14 1999 · Poisson s ratio is positive being close to 1/3 for most 17 18 and several types of rocks 19 20 with damping properties 34 and so on. 2.2. Auxetic microporous polymers The ﬁrst example of an auxetic macroporous polymer identiﬁed was a form of expanded PTFE 13 . The mi-

Get Price### Evaluation of Auxetic Polymeric Structures for Use in

Auxetic materials known as materials with negative Poisson s ratio (NPR) have many promising application areas. However there are only few natural and man-made materials such as certain living bone tissues certain rocks and minerals polymeric honeycombs microporous polytetrafluoroethylene (PTFE) foams and carbon-fiber-reinforced epoxy composite laminate panels that possess this property.

Get Price### Auxetic two-dimensional lattices with Poisson s ratio

Poisson s ratio ν is an indication of the mechanical properties of a medium to deform mainly deviatorically or isotropically as described by the ratio K/μ between the bulk and the shear modulus ranging from a so-called rubbery behaviour at the upper limit of ν to a dilatational behaviour at the lower limit of ν where for a three

Get Price### Topology optimisation of Meta Material with Negative

May 24 2017 · The Poisson s ratio is defined as the ratio of the lateral strain to that of the axial strain. The Poisson s ratio has interesting properties when it is not within the normal range. This parameter can have a negative value and such materials are termed as auxetic materials.

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In materials science and solid mechanics Poisson s ratio is a measure of the Poisson effect the deformation (expansion or contraction) of a material in directions perpendicular to the specific direction of loading.The value of Poisson s ratio is the negative of the ratio of transverse strain to axial strain.For small values of these changes is the amount of transversal elongation divided by

Get Price### Auxetic metamaterials from disordered networks PNAS

Recent work indicates that selective pruning of disordered networks of nodes connected by bonds can generate materials with nontrivial mechanical properties including auxetic networks having a negative Poisson s ratio ν. Until now auxetic networks created based on this strategy have not been successfully realized in experiment. Here a model that includes angle-bending forces and the

Get Price### Toward Negative Poisson Ratio Polymers through Molecular

Three-dimensional cellular structures with negative Poisson s ratio and negative compressibility properties. Proceedings of the Royal Society A Mathematical Physical and Engineering Sciences 2012 468 (2146) .

Get Price### Poisson ratio and bulk lattice constant of (Sr0.25La0.75

Aug 26 2019 · About 30 nm thick (001)-oriented (Sr 0.25 La 0.75)CrO 3 (SLCO) epitaxial thin films were grown by solid-source oxide molecular beam epitaxy on four different single-crystalline cubic or pseudocubic (001)-oriented oxide substrates LaAlO 3 (LaAlO 3) 0.3 (Sr 2 AlTaO 6) 0.7 SrTiO 3 and DyScO 3 which result in lattice mismatch ranging from –2 to 1.7 .All the films are of high-quality

Get Price### Auxetic materials materials with negative poisson s ratio

Jul 22 2017 · Poisson s ratio is a measure of the transverse strain relative to longitudinal strain Fung et al.1 Claimed that the Poisson s ratio is bounded between -1 and 0.5 for a linear elastic isotropic material. Cork is the material with zero Poisson s ratio. It was shown in the work of Ting2 that for anisotropic materials Poisson s ratio can be

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