Positive or negative Poynting effect? The role of adscititious inequalities in hyperelastic materials

Motivated by recent experiments on biopolymer gels whereby the reverse of the usual (positive) Poynting effect was observed, we investigate the effect of the so-called “adscititious inequalities” on the behaviour of hyperelastic materials subject to shear. We first demonstrate that for homogeneous i...

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Main Authors: Mihai, L, Goriely, A
Format: Journal article
Published: Royal Society 2011
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author Mihai, L
Goriely, A
author_facet Mihai, L
Goriely, A
author_sort Mihai, L
collection OXFORD
description Motivated by recent experiments on biopolymer gels whereby the reverse of the usual (positive) Poynting effect was observed, we investigate the effect of the so-called “adscititious inequalities” on the behaviour of hyperelastic materials subject to shear. We first demonstrate that for homogeneous isotropic materials subject to pure shear, the resulting deformation consists of a triaxial stretch combined with a simple shear in the direction of the shear force if and only if the Baker-Ericksen inequalities hold. Then for a cube deformed under pure shear, the positive Poynting effect occurs if the “sheared faces spread apart”, whereas the negative Poynting effect is obtained if the “sheared faces draw together”. Similarly, under simple shear deformation, the positive Poynting effect is obtained if the “sheared faces tend to spread apart”, whereas the negative Poynting effect occurs if the “sheared faces tend to draw together”. When the Poynting effect occurs under simple shear, it is reasonable to assume that the same sign Poynting effect is obtained also under pure shear. Since the observation of the negative Poynting effect in semiflexible biopolymers implies that the (stronger) empirical inequalities may not hold, we conclude that these inequalities must not be imposed when such materials are described.
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spelling oxford-uuid:0afea080-225f-40ee-a5f1-a66ba034d8b02022-03-26T09:27:07ZPositive or negative Poynting effect? The role of adscititious inequalities in hyperelastic materialsJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:0afea080-225f-40ee-a5f1-a66ba034d8b0Mathematical Institute - ePrintsRoyal Society2011Mihai, LGoriely, AMotivated by recent experiments on biopolymer gels whereby the reverse of the usual (positive) Poynting effect was observed, we investigate the effect of the so-called “adscititious inequalities” on the behaviour of hyperelastic materials subject to shear. We first demonstrate that for homogeneous isotropic materials subject to pure shear, the resulting deformation consists of a triaxial stretch combined with a simple shear in the direction of the shear force if and only if the Baker-Ericksen inequalities hold. Then for a cube deformed under pure shear, the positive Poynting effect occurs if the “sheared faces spread apart”, whereas the negative Poynting effect is obtained if the “sheared faces draw together”. Similarly, under simple shear deformation, the positive Poynting effect is obtained if the “sheared faces tend to spread apart”, whereas the negative Poynting effect occurs if the “sheared faces tend to draw together”. When the Poynting effect occurs under simple shear, it is reasonable to assume that the same sign Poynting effect is obtained also under pure shear. Since the observation of the negative Poynting effect in semiflexible biopolymers implies that the (stronger) empirical inequalities may not hold, we conclude that these inequalities must not be imposed when such materials are described.
spellingShingle Mihai, L
Goriely, A
Positive or negative Poynting effect? The role of adscititious inequalities in hyperelastic materials
title Positive or negative Poynting effect? The role of adscititious inequalities in hyperelastic materials
title_full Positive or negative Poynting effect? The role of adscititious inequalities in hyperelastic materials
title_fullStr Positive or negative Poynting effect? The role of adscititious inequalities in hyperelastic materials
title_full_unstemmed Positive or negative Poynting effect? The role of adscititious inequalities in hyperelastic materials
title_short Positive or negative Poynting effect? The role of adscititious inequalities in hyperelastic materials
title_sort positive or negative poynting effect the role of adscititious inequalities in hyperelastic materials
work_keys_str_mv AT mihail positiveornegativepoyntingeffecttheroleofadscititiousinequalitiesinhyperelasticmaterials
AT gorielya positiveornegativepoyntingeffecttheroleofadscititiousinequalitiesinhyperelasticmaterials