Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, CA 92093-0411, USA.
Acta Biomater. 2010 Feb;6(2):319-30. doi: 10.1016/j.actbio.2009.06.033. Epub 2009 Jul 3.
The structure and mechanical properties of the horns from a desert bighorn sheep, Ovis canadensis, were examined. Horns must be strong and durable as they are subjected to extreme loading impacts, making them superior structural materials. Horns are composed of alpha-keratin, a fibrous, structural protein found in hair, nails, claws and hooves. Horns have a lamellar structure (2-5microm in thickness) stacked in the radial direction with tubules (approximately 40x100microm in diameter) dispersed between the lamellae, extending along the length of the horn in the growth direction. Compression and bending tests were conducted in both rehydrated and ambient dried conditions. The yield strength and elastic modulus are anisotropic and are correlated with the orientation of the tubules. Rehydrated samples showed significant loss of strength and modulus. Microscopy of fractured samples revealed several toughening mechanisms: delamination and ligament bridging in bending and delamination and microbuckling of the lamellae in compression.
对沙漠大角羊（Ovis canadensis）的角的结构和力学性能进行了研究。由于角承受着极端的加载冲击，因此必须具有高强度和耐用性，使其成为优越的结构材料。角由角蛋白组成，角蛋白是一种纤维状结构蛋白，存在于毛发、指甲、爪子和蹄子中。角具有层状结构（厚度为 2-5 微米），沿径向堆叠，管腔（直径约为 40x100 微米）散布在层之间，沿角的生长方向延伸。在水合和环境干燥条件下进行了压缩和弯曲测试。屈服强度和弹性模量具有各向异性，并与管腔的取向相关。水合样品的强度和模量显著降低。对断裂样品的显微镜观察揭示了几种增韧机制：弯曲时的分层和韧带桥接，以及压缩时的层状分层和微屈曲。
