Mechanics of collagen-hydroxyapatite model nanocomposites

F Libonati and AK Nair and L Vergani and MJ Buehler, MECHANICS RESEARCH COMMUNICATIONS, 58, 17-23 (2014).

DOI: 10.1016/j.mechrescom.2013.08.008

Bone is a hierarchical biological composite made of a mineral component (hydroxyapatite crystals) and an organic part (collagen molecules). Small-scale deformation phenomena that occur in bone are thought to have a significant influence on the large scale behavior of this material. However, the nanoscale behavior of collagen-hydroxyapatite composites is still relatively poorly understood. Here we present a molecular dynamics study of a bone model nanocomposite that consist of a simple sandwich structure of collagen and hydroxyapatite, exposed to shear-dominated loading. We assess how the geometry of the composite enhances the strength, stiffness and capacity to dissipate mechanical energy. We find that H-bonds between collagen and hydroxyapatite play an important role in increasing the resistance against catastrophic failure by increasing the fracture energy through a stick-slip mechanism. (C) 2013 Elsevier Ltd. All rights reserved.

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