Effects of direction and shape of osteocyte lacunae on resisting impact and micro-damage of osteon.

Animal bones bear varied impact loadings during in the movements of animals. The impact resistance and micro-damage of bones are influenced by their various microstructures at different length scales. In this paper, according to the microstructure of osteon, three 2-D microstructure models (circumferential ellipse lacunae (Model A), radial elliptical lacunae (Model B) and circular lacunae (Model C) were constructed for investigating the influences of the arranged direction and shape of osteocyte lacunae on resisting impact and micro-damage. Impact analytical results show that the maximal stress of the Model A is the minimum and that of the Model B is the maximal under same boundary conditions, which indicates that the circumferentially elliptical lacunae, whose minor axis is along the radial direction of the osteon (Model A), can enhance impact resistance of osteons effectively. The investigated results of the progressive damage show that the circumferentially ellipse lacunae (Model A) are more benefit to resist micro-damage and that the micro-cracks in the model are mainly along the circumferential direction of the osteon. These investigated results for the novel microstructures found in osteon can serve engineers as guidance in the designs of biomimetic and bioinspired tubular structures or materials for engineering applications.