Title: Plastic behaviour of microstructural constituents of cortical bone tissue: a nanoindentation study

Authors: Adel A. Abdel-Wahab; Vadim V. Silberschmidt

Addresses: Wolfson School of Mechanical and Manufacturing Engineering, Loughborough University, Loughborough, Leicestershire, LE11 3TU, UK ' Wolfson School of Mechanical and Manufacturing Engineering, Loughborough University, Loughborough, Leicestershire, LE11 3TU, UK

Abstract: A mechanical behaviour of bone tissues is defined by mechanical properties of its microstructural constituents. Also, those properties are important as an input for finite-element models of cortical bone to simulate its deformation and fracture behaviours at the microstructural level. The aim of this study was to investigate a post-yield behaviour of osteonal cortical bone's microstructural constituents at different loading rates, maximum load levels and dwell times; nanoindentation with a spherical-diamond-tip indenter was employed to determine it. The nanoindentation results revealed significant difference in stiffness values of cortical bone's microstructural features - interstitial matrix and osteons. Similarly, interstitial matrix exhibited a stiffer post-yield behaviour compared to that of osteons that reflects the relationship between the post-yield behaviour and collagen maturity. In addition, both osteons and interstitial matrix demonstrated a time-dependent behaviour. However, in order to assess elastic-plastic behaviour accurately, an effect of viscosity on nanoindentation results was reduced by using a time-delay method.

Keywords: cortical bone; nanoindentation; flow stress; flow strain; osteons; interstitial matrix; post-yield behaviour; plastic behaviour; microstructural constituents; mechanical behaviour; microstructure; bone tissues; finite element method; FEM; modelling; simulation; deformation; fracture; stiffness values; collagen maturity; viscosity; nanotechnology.

DOI: 10.1504/IJECB.2013.056521

International Journal of Experimental and Computational Biomechanics, 2013 Vol.2 No.2, pp.136 - 157

Received: 18 May 2012
Accepted: 02 Jan 2013
Published online: 12 Jul 2014 *

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