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A combined experimental and modelling approach to aortic valve viscoelasticity in tensile deformation

A combined experimental and modelling approach to aortic valve viscoelasticity in tensile deformation
A combined experimental and modelling approach to aortic valve viscoelasticity in tensile deformation
The quasi-static mechanical behaviour of the aortic valve (AV) is highly non-linear and anisotropic in nature and reflects the complex collagen fibre kinematics in response to applied loading. However, little is known about the viscoelastic behaviour of the AV. The aim of this study was to investigate porcine AV tissue under uniaxial tensile deformation, in order to establish the directional dependence of its viscoelastic behaviour. Rate dependency associated with different mechanical properties was investigated, and a new viscoelastic model incorporating rate effects developed, based on the Kelvin-Voigt model. Even at low applied loads, experimental results showed rate dependency in the stress-strain response, and also hysteresis and dissipation effects. Furthermore, corresponding values of each parameter depended on the loading direction. The model successfully predicted the experimental data and indicated a 'shear-thinning' behaviour. By extrapolating the experimental data to that at physiological strain rates, the model predicts viscous damping coefficients of 8.3 MPa s and 3.9 MPa s, in circumferential and radial directions, respectively. This implies that the native AV offers minimal resistance to internal shear forces induced by blood flow, a potentially critical design feature for substitute implants. These data suggest that the mechanical behaviour of the AV cannot be thoroughly characterised by elastic deformation and fibre recruitment assumptions alone
0957-4530
253-262
Anssari-Benam, Afshin
176110a2-cb00-496f-89fb-a09368dc4514
Bader, Dan L.
9884d4f6-2607-4d48-bf0c-62bdcc0d1dbf
Screen, Hazel R.C.
c39bc651-8aea-4c56-ba80-53bc0b308441
Anssari-Benam, Afshin
176110a2-cb00-496f-89fb-a09368dc4514
Bader, Dan L.
9884d4f6-2607-4d48-bf0c-62bdcc0d1dbf
Screen, Hazel R.C.
c39bc651-8aea-4c56-ba80-53bc0b308441

Anssari-Benam, Afshin, Bader, Dan L. and Screen, Hazel R.C. (2011) A combined experimental and modelling approach to aortic valve viscoelasticity in tensile deformation. Journal of Materials Science: Materials in Medicine, 22 (2), 253-262. (doi:10.1007/s10856-010-4210-6). (PMID:21221737)

Record type: Article

Abstract

The quasi-static mechanical behaviour of the aortic valve (AV) is highly non-linear and anisotropic in nature and reflects the complex collagen fibre kinematics in response to applied loading. However, little is known about the viscoelastic behaviour of the AV. The aim of this study was to investigate porcine AV tissue under uniaxial tensile deformation, in order to establish the directional dependence of its viscoelastic behaviour. Rate dependency associated with different mechanical properties was investigated, and a new viscoelastic model incorporating rate effects developed, based on the Kelvin-Voigt model. Even at low applied loads, experimental results showed rate dependency in the stress-strain response, and also hysteresis and dissipation effects. Furthermore, corresponding values of each parameter depended on the loading direction. The model successfully predicted the experimental data and indicated a 'shear-thinning' behaviour. By extrapolating the experimental data to that at physiological strain rates, the model predicts viscous damping coefficients of 8.3 MPa s and 3.9 MPa s, in circumferential and radial directions, respectively. This implies that the native AV offers minimal resistance to internal shear forces induced by blood flow, a potentially critical design feature for substitute implants. These data suggest that the mechanical behaviour of the AV cannot be thoroughly characterised by elastic deformation and fibre recruitment assumptions alone

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Published date: February 2011

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Local EPrints ID: 189255
URI: https://eprints.soton.ac.uk/id/eprint/189255
ISSN: 0957-4530
PURE UUID: 26e9fedd-8743-4f2e-9b44-e033d6cfc423
ORCID for Dan L. Bader: ORCID iD orcid.org/0000-0002-1208-3507

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Date deposited: 02 Jun 2011 14:16
Last modified: 06 Jun 2018 12:32

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Contributors

Author: Afshin Anssari-Benam
Author: Dan L. Bader ORCID iD
Author: Hazel R.C. Screen

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