ABSTRACT
Objective To Investigate the toughness mechanism of the hierarchical and eximious micro-nanostructures from shankbone biocomposite. Methods The hierarchical micro-nanostructures of a mature shankbone were observed with a scanning electronic microscope and then to explore the toughness mechanism of this shankbone by the analyses on the models with hierarchical micro-nanostructures. Results The shankbone was made from a kind of biocomposite with hierarchical micro-nanostructures, consisting of hydroxyapatite and collagen protein matters. The micro-nanostructural model analyses at different scales indicated that the multilayer microstructure of the bone increased its fracture energy and the crossed microstructure of the hydroxyapatite fiber sheets as well as its long and thin shape size enhanced the maximum pullout energy of the fiber sheets. Conclusions The hierarchical and eximious micro-nanostructures in the bone endow the shankbone with high fracture toughness, and can be applied to the design of biomimetic composites.