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Nano-scale mechanisms explain the stiffening and strengthening of ligament tissue with increasing strain rate

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posted on 12.03.2018 by Angelo Karunaratne, Simin Li, Anthony M.J. Bull
Ligament failure is a major societal burden causing disability and pain. Failure is caused by trauma at high loading rates. At the macroscopic level increasing strain rates cause an increase in failure stress and modulus, but the mechanism for this strain rate dependency is not known. Here we investigate the nano scale mechanical property changes of human ligament using mechanical testing combined with synchrotron X-ray diffraction. With increasing strain rate, we observe a significant increase in fibril modulus and a reduction of fibril to tissue strain ratio, revealing that tissue-level stiffening is mainly due to the stiffening of collagen fibrils. Further, we show that the reduction in fibril deformation at higher strain rates is due to reduced molecular strain and fibrillar gaps, and is associated with rapid disruption of matrix-fibril bonding. This reduction in number of interfibrillar cross-links explains the changes in fibril strain; this is verified through computational modelling.

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  • Mechanical, Electrical and Manufacturing Engineering

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Scientific Reportsvolume

Citation

KARUNARATNE, A., LI, S. and BULL, A.M.J., 2018. Nano-scale mechanisms explain the stiffening and strengthening of ligament tissue with increasing strain rate. Scientific Reports, 8: 3707.

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© the Authors. Published by the Nature Publishing Group

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This work is made available according to the conditions of the Creative Commons Attribution 4.0 International (CC BY 4.0) licence. Full details of this licence are available at: http://creativecommons.org/licenses/ by/4.0/

Acceptance date

10/02/2018

Publication date

2018-02-27

Notes

This is an Open Access Article. It is published by Nature under the Creative Commons Attribution 4.0 Unported Licence (CC BY). Full details of this licence are available at: http://creativecommons.org/licenses/by/4.0/

ISSN

2045-2322

eISSN

2045-2322

Language

en

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