Regensburg 2007 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 35: SYBM Bioinspired Materials

MM 35.18: Poster

Donnerstag, 29. März 2007, 18:45–20:45, H16

Evaluation of different constitutive models for the mechanical behavior of bone at submicron scale — •Svetoslav Nikolov, Helge Fabritius, Christoph Sachs, and Dierk Raabe — Max-Planck-Institut für Eisenforchung, 40237 Düsseldorf, Germany

Hard biological tissues, such as vertebrate bone, show a complex hierarchical structure at all length scales. The basic structural unit of bone is a fibrous collagen matrix containing small hydroxyapatite crystals in the form of platelets. Here we focus on the constitutive modeling of a bundle of these mineralized collagen fibrils in order to predict their mechanical response. The material is modeled via a two-step homogenization procedure * a first homogenization step at the level of one single mineralized fibril, and a second one at the level of a fibril bundle embedded in an extrafibrillar matrix. We compare different combinations of homogenization models, such as shear-lag models, self-consistent estimates, Mori-Tanaka and double-inclusion homogenization schemes, in order to elucidate which two-step homogenization scheme better reproduce the mechanical data available from experiments. We additionally perform a parametric study on the microstructure parameters, such as the aspect ratio and the volume fraction of collagen fibrils and apatite platelets, the Young*s modulus of the constituents and their density in order to extract some structural optimization principles involved in the natural formation of hard tissues.