000004948 001__ 4948
000004948 005__ 20141119144607.0
000004948 04107 $$aeng
000004948 046__ $$k2002-06-02
000004948 100__ $$aHellmich, Christian
000004948 24500 $$aA UNIFIED CONTINUUM MICROMECHANICS APPROACH TO THE ULTRASTRUCTURAL ELASTICITY OF MINERALIZED TISSUES

000004948 24630 $$n15.$$pProceedings of the 15th ASCE Engineering Mechanics Division Conference
000004948 260__ $$bColumbia University in the City of New York
000004948 506__ $$arestricted
000004948 520__ $$2eng$$aWe recently found that mineralized tissues (mineralized tendons and bones), at an observation scale of some microns, are dense isotropic hydroxyapatite crystal foams which are reinforced unidirectionally by (organic) collagen molecules. The collagen reinforcement is mechanically activated by crosslinks between collagen assemblies and hydroxyapatite. With this morphology in mind, we develop a continuum micromechanics model for the ultrastructural stiffness of mineralized tissues. The homogenization is achieved in two steps: At a scale of some hundred nanometers, the isotropic crystal foam is represented as a two-phase polycrystal composed of a hydroxyapatite crystal phase and a non-minerally phase filling the inter-crystalline space. At a scale above of some five to ten micrometers, the polycrystal plays the role of a connected matrix, in which a collagen inclusion phase is embedded. The input for the model are the mineral volume fraction and the collagen volume fraction, which are species and tissue-type specific. Then, on the basis of four (tissue-independent) intrinsic micromechanical stiffness constants, the model is able to predict the full ultrastructural stiffness tensor of mineralized tissues, from lowmineralized turkey leg tendon to highly anisotropic human bones, and high-mineralized isotropic ear bones of whales. 

000004948 540__ $$aText je chráněný podle autorského zákona č. 121/2000 Sb.
000004948 653__ $$abone elasticity, crystal foam, collagen reinforcement, continuum micromechanics

000004948 7112_ $$a15th ASCE Engineering Mechanics Division Conference$$cNew York (US)$$d2002-06-02 / 2002-06-05$$gEM2002
000004948 720__ $$aHellmich, Christian$$iUlm, Franz-Josef
000004948 8560_ $$ffischerc@itam.cas.cz
000004948 8564_ $$s194936$$uhttps://invenio.itam.cas.cz/record/4948/files/596.pdf$$yOriginal version of the author's contribution as presented on CD, .
000004948 962__ $$r4594
000004948 980__ $$aPAPER