De Falco P, Barbieri E, Pugno N, Gupta H S
School of Engineering and Material Science, Queen Mary University of London, London E1 4NS, United Kingdom.
Laboratory of Bio-Inspired and Graphene Nanomechanics, Department of Civil, Environmental and Mechanical Engineering, University of Trento, Trento 38122, Italy.
ACS Biomater Sci Eng. 2017 Nov 13;3(11):2779-2787. doi: 10.1021/acsbiomaterials.6b00637. Epub 2017 Jan 12.
The high toughness and work to fracture of hierarchical composites, like antler bone, involve structural mechanisms at the molecular, nano-, and micro scales, which are not completely explored. A key characteristic of the high energy absorption of such materials is the large hysteresis during cyclic loading, but its origin remains unknown. In situ synchrotron X-ray diffraction tests during tensile loading of antler bone showed heterogeneous fibrillar deformation and hysteresis. To explain the origin of these mechanisms from the nanostructure of antler bone, here we develop a class of finite-element fibril models whose predictions are compared to experimental data across a range of potential composite architectures. We demonstrate that the key structural motif enabling a match to experimental data is an axially staggered arrangement of stiff mineralized collagen fibrils coupled with weak, damageable interfibrillar interfaces.
像鹿角这样的分级复合材料具有高韧性和断裂功，其涉及分子、纳米和微观尺度的结构机制，这些机制尚未得到充分探索。这类材料高能量吸收的一个关键特征是循环加载过程中的大滞后现象，但其起源仍然未知。鹿角拉伸加载过程中的原位同步辐射X射线衍射测试显示出非均匀的纤维状变形和滞后现象。为了从鹿角的纳米结构解释这些机制的起源，我们在此开发了一类有限元纤维模型，并将其预测结果与一系列潜在复合结构的实验数据进行比较。我们证明，能够与实验数据匹配的关键结构 motif 是硬矿化胶原纤维的轴向交错排列以及弱的、易受损的纤维间界面。
