Regensburg 2007 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 35: SYBM Bioinspired Materials

MM 35.11: Vortrag

Donnerstag, 29. März 2007, 17:45–18:00, H16

Influence of structural principles on the mechanics and efficiency of different biological materials using lobster cuticle as a model material — •Christoph Sachs, Helge Fabritius, Svetoslav Nikolov, and Dierk Raabe — Max-Planck-Institut für Eisenforschung, 40237 Düsseldorf, Germany

The cuticle of the lobster Homarus americanus is a nano-composite material consisting of a matrix of chitin-protein fibers associated with various amounts of crystalline and amorphous calcium carbonate and is organized hierarchically on all length scales. The chitin protein fibers are arranged in horizontal planes where the long axes of the fibers are all oriented in the same direction. These planes are stacked with the orientation of the fibers in superimposed layers rotating gradually around the normal axis of the cuticle, thus creating a typical twisted plywood structure. Additionally, the fibers are arranged around the cavities originating from the extremely well developed pore canal system of the lobster which gives the structure a honeycomb-like appearance. Tensile, compression and shear tests performed on both cuticle in its natural hydrated and in the dry state show that both structural principles, twisted plywood and honeycomb, are reflected in the obtained mechanical data of the material. The comparison of hard mineralized cuticle and unmineralized joint membranes shows the influence of the incorporation of minerals on the performance of the material, which is optimized for the role the material has to play in the living organism. The obtained mechanical properties are used to deduce general analytical models describing the mechanics of different biological materials.