Open Access

ARTICLE

Effects of Transverse Shear on Strain Stiffening of Biological Fiber Networks

H. Jiang^1,2, B. Yang¹, S. Liu³

1 Dept. of Mech. & Aerospace Engr., Univ. of Texas at Arlington, Arlington, TX 76019.
2 Corresponding author. Email: haojiang@uta.edu; Tel: +1 817 272 1496; Fax: +1 817 272 2952
3 State Key Laboratory of Digital Manufacturing Equipment and Technology, Huazhong University of Science and Technology, Wuhan 430074, China.

Computers, Materials & Continua 2013, 38(2), 61-77. https://doi.org/10.3970/cmc.2013.038.061

Abstract

Actin, fibrin and collagen fiber networks are typical hierarchical biological materials formed by bundling fibrils into fibers and branching/adjoining fibers into networks. The bundled fibrils interact with each other through weak van der Waals forces and, in some cases, additional spotted covalent crosslinks. In the present work, we apply Timoshenko's beam theory that takes into account the effect of transverse shear between fibrils in each bundle to study the overall mechanical behaviors of such fiber networks. Previous experimental studies suggested that these fibers are initially loose bundles. Based on the evidence, it is hypothesized that the fibers undergo transitions from an initially loose to a tightened (due to strain effects) and finally back to a loose (due to damage) bundle under progressive loading. In correspondence, there can be identified three stages of strain stiffening and softening for the overall network deformation, consistent with results of a recent experimental in-situ neutron scattering study of fibrin networks. Finite element models are developed to examine these effects.

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Keywords

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