A new anisotropic soft tissue model for elimination of unphysical auxetic behaviour

JOURNAL OF BIOMECHANICS

卷:111

Article

Fereidoonnezhad, B.¹  O'Connor, C.¹  McGarry, J. P.¹ 

[1] Natl Univ Ireland Galway, Sch Engn, Galway, Ireland

关键词: Hyperelasticity;    Constitutive modeling;    Anisotropy;    Soft tissue;    Auxetic behaviour;    Strain-stiffening fibre-matrix model;   

DOI  :  10.1016/j.jbiomech.2020.110006

来源: Elsevier

【 摘 要 】

Auxetic behaviour, the unphysical transverse expansion during uniaxial tension, is a common and undesirable feature of classical anisotropic hyperelastic constitutive models for soft tissue. In this study we uncover the underlying mechanism of such behaviour; high levels of in-plane compaction occurs due to increasing tension in strain-stiffening fibres, leading to unphysical out-of-plane expansion. We demonstrate that auxetic behaviour is primarily influenced by the ratio of fibre to matrix stiffness, and is accentuated by strain-stiffening fibres in a constant stiffness matrix (e.g., the widely used neo-Hookean matrix with exponentially stiffening fibres). We propose a new bilinear strain stiffening fibre and matrix (BLFM) model which allows close control of the fibre-matrix stiffness ratio, thereby robustly eliminating auxetic behaviour. We demonstrate that our model provides accurate prediction of experimentally observed outof-plane compaction, in addition to stress-stretch anisotropy, for arterial tissue subjected to uniaxial tension testing. (C) 2020 Published by Elsevier Ltd.

【 授权许可】

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