Ductile sliding between mineral crystals followed by rupture of collagen crosslinks: Experimentally supported micromechanical explanation of bone strengthReport as inadecuate




Ductile sliding between mineral crystals followed by rupture of collagen crosslinks: Experimentally supported micromechanical explanation of bone strength - Download this document for free, or read online. Document in PDF available to download.

* Corresponding author 1 Vienna University of Technology Vienna 2 NAVIER UMR 8205 - Laboratoire Navier 3 Multi-échelle - Modélisation et expérimentation multi-échelle pour les solides hétérogènes NAVIER UMR 8205 - Laboratoire Navier

Abstract : There is an ongoing discussion on how bone strength could be explained from its internal structure and composition. Reviewing recent experimental and molecular dynamics studies, we here propose a new vision on bone material failure: mutual ductile sliding of hydroxyapatite mineral crystals along layered water films is followed by rupture of collagen crosslinks. In order to cast this vision into a mathematical form, a multiscale continuum micromechanics theory for upscaling of elastoplastic properties is developed, based on the concept of concentration and influence tensors for eigenstressed microheterogeneous materials. The model reflects bone-s hierarchical organization, in terms of representative volume elements for cortical bone, for extravascular and extracellular bone material, for mineralized fibrils and the extrafibrillar space, and for wet collagen. In order to get access to the stress states at the interfaces between crystals, the extrafibrillar mineral is resolved into an infinite amount of cylindrical material phases oriented in all directions in space. The multiscale micromechanics model is shown to be able to satisfactorily predict the strength characteristics of different bones from different species, on the basis of their mineral-collagen content, their intercrystalline, intermolecular, lacunar, and vascular porosities, and the elastic and strength properties of hydroxyapatite and molecular collagen.

Keywords : Bone Strength Multiscale continuum micromechanics Hydroxyapatite Collagen





Author: Andreas Fritsch - Christian Hellmich - Luc Dormieux -

Source: https://hal.archives-ouvertes.fr/



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