Poisson's Ratio in Skin

Lees, Caroline; Vincent, Julian F. V.; Hillerton, J.E.

doi:10.3233/bme-1991-1104

Cited by 141 publications

(86 citation statements)

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“…In theory, fibrous materials can exhibit a wide range of Poisson's ratios, including negative ones 10, 11. The observance of auxetic behaviour in cow teat skin led Lees et al 12 to conclude that the cow teat skin is a network of fibres rather than a continuum. Planar fibrous materials such as paper and sintered mats of compressed metallic fibres have also been shown by experiment to exhibit out‐of‐plane negative Poisson's ratios 13, 14, and recently negative in‐plane Poisson's ratios have been reported in nanotube sheets 15.…”

Section: Introductionmentioning

confidence: 99%

Modelling the negative Poisson's ratio of compressed fused fibre networks

Tatlier

Berhan

2009

Physica Status Solidi (b)

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Examples of auxetic fused fibrous assemblies can be found among both natural and synthetic materials. In theory, fibrous network materials can exhibit negative Poisson's ratios, yet the deformation mechanisms and parameters which give rise to a negative Poisson's ratio in disordered fibrous materials are not well understood, and this class of auxetic materials remains largely under‐explored. The potential applications of auxetic fibre networks include their use as reinforcement in composites. The process of embedding auxetic random fibrous networks in a polymer matrix is an attractive alternate route to the manufacture of auxetic composites; however, before such an approach can be developed, a methodology for designing fibrous networks with the desired negative Poisson's ratios must first be established. This requires an understanding of the factors which bring about negative Poisson's ratios in these materials. In this work, we present a modelling approach to study the auxetic behaviour of compressed fused fibrous networks. Finite element analyses of three‐dimensional stochastic fibre networks were performed to gain insight into the effects of parameters such as network anisotropy, network density and degree of network compression on the out‐of‐plane Poisson's ratio. The simulation results suggest that compression and anisotropy are the critical parameters that give rise to auxetic behaviour in these materials. We comment on the use of this model to inform the design of fibrous auxetic materials across different length scales, and on the feasibility of developing auxetic composites by using auxetic fibrous networks as the reinforcing phase. Preliminary experimental results indicate that this approach is a promising route in the pursuit of negative Poisson's ratio composites.

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Section: Introductionmentioning

confidence: 99%

Modelling the negative Poisson's ratio of compressed fused fibre networks

Tatlier

Berhan

2009

Physica Status Solidi (b)

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“… While most biological materials have Poisson's ratio that fall at or below 0.5, some values for skin have been reported as high as 1.6–2.5 (Lees et al, ; Frolich et al, ; Lucas, ). If these values are correct, it means skin cannot be modeled as a linearly elastic material.…”

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confidence: 99%

Food mechanical properties and dietary ecology

Berthaume

2016

American J Phys Anthropol

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Interdisciplinary research has benefitted the fields of anthropology and engineering for decades: a classic example being the application of material science to the field of feeding biomechanics. However, after decades of research, discordances have developed in how mechanical properties are defined, measured, calculated, and used due to disharmonies between and within fields. This is highlighted by "toughness," or energy release rate, the comparison of incomparable tests (i.e., the scissors and wedge tests), and the comparison of incomparable metrics (i.e., the stress and displacement-limited indices). Furthermore, while material scientists report on a myriad of mechanical properties, it is common for feeding biomechanics studies to report on just one (energy release rate) or two (energy release rate and Young's modulus), which may or may not be the most appropriate for understanding feeding mechanics.Here, I review portions of materials science important to feeding biomechanists, discussing some of the basic assumptions, tests, and measurements. Next, I provide an overview of what is mechanically important during feeding, and discuss the application of mechanical property tests to feeding biomechanics. I also explain how 1) toughness measures gathered with the scissors, wedge, razor, and/or punch and die tests on non-linearly elastic brittle materials are not mechanical properties, 2) scissors and wedge tests are not comparable and 3) the stress and displacement-limited indices are not comparable. Finally, I discuss what data gathered thus far can be best used for, and discuss the future of the field, urging researchers to challenge underlying assumptions in currently used methods to gain a better understanding between primate masticatory morphology and diet. Am J Phys Anthropol 159:S79-S104, 2016. V C 2016 American Association of Physical Anthropologists "If I have seen further it is by standing on ye shoulders of Giants." Sir Isaac Newton Materials science is a branch of engineering that "involves investigating the relationships that exist between the structures and properties of materials (pg. 3, Callister (2004))," where structures are defined by the arrangement and internal components of a material (e.g., atomic structure). Over the past several decades, anthropologists and biologists have been measuring/calculating mechanical properties of dietary items to investigate differences in feeding strategies, feeding adaptations, and plant defenses (Choong et al., 1992;Hill and Lucas, 1996;Wright and Vincent, 1996;Darvell et al., 1996;Agrawal et al., 1997;Strait and Vincent, 1998;Yamashita, 1998Yamashita, , 2002Yamashita, , 2003Yamashita, , 2008Lucas et al., 2000Lucas et al., , 2001Lucas et al., , 2009Lucas et al., , 2011Agrawal and Lucas, 2003;Balsamo et al., 2003;Lucas, 2004;Elgart-Berry, 2004;Williams et al., 2005;Teaford et al., 2006;Quyet et al., 2007;Freeman and Lemen, 2007b;Wright et al., 2008;Dominy et al., 2008;Norconk et al., 2009b;Vogel et al., 2009Vogel et al., , 2014Wieczkowski, 2009;Yamas...

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“…Similar levels of auxeticity have been observed in silicates (α-cristobalite, zeolites) attributed to rotation of "building blocks" [13,14]; cubic metals when stretched in [110] direction [11]; liquid crystalline polymers (eg. carbocyclic-, poly(phenylacetylene)-networks) due to the connectivity between the rigid centre region and the flexible ends of elongated organic molecules [2,[15][16][17] and skin tissue (cat, cow teat) attributed to their fibrillar structure [18,19]. Man-made auxetic materials include re-entrant or hinged honeycombs and foams, which exhibit auxeticity due to the unfolding of re-entrant cells [1,[20][21][22][23]; microporous polymers (Polytetrafluoroethylene (PTFE), ultra-high molecular weight polyethylene (UHMWPE), Polypropylene (PP)) [2,24,25].…”

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confidence: 99%

Out-of-plane auxeticity in sintered fibre network mats

2015

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Fibre network mats composed of stainless steel exhibit an unusually large out-ofplane auxeticity (i.e. high negative Poisson's ratio ν) when subjected to in-plane tensile loading. In situ observations in a scanning electron microscope suggest that this is attributable to fibre segment straightening. An investigation was carried out on the effects of fibre volume fraction and network thickness on the auxetic response.Weak inter-layer bonding, high fibre content and low network thickness were found to amplify the auxetic effect.

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Poisson's Ratio in Skin

Cited by 141 publications

References 0 publications

Modelling the negative Poisson's ratio of compressed fused fibre networks

Modelling the negative Poisson's ratio of compressed fused fibre networks

Food mechanical properties and dietary ecology

Out-of-plane auxeticity in sintered fibre network mats

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