Crack propagation in bone on the scale of mineralized collagen fibrils: role of polymers with sacrificial bonds and hidden length.
Crack propagation in bone on the scale of mineralized collagen fibrils: role of polymers with sacrificial bonds and hidden length.
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DOI：
10.1016/j.bone.2014.07.035
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发表时间：
2014-08
期刊：
影响因子：
4.1
通讯作者：
Wenyi Wang;A. Elbanna
中科院分区：
文献类型：
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作者：
Wenyi Wang;A. Elbanna
结构分子中的牺牲键和隐藏长度（shbhl）提供了纳米尺度下能量耗散的机制。据推测，它们的存在比在没有这些特征的材料中观察到的断裂韧性更大。在这里，我们使用矿化胶原纤维与shbhl系统在聚合物界面上滑动的简化模型来研究这一假设。采用一维粗粒度非线性弹簧-质量系统对纤维进行建模。用速率和位移本构方程来描述聚合物体系的力学性能。该模型量化了界面韧性如何随聚合物密度和牺牲键数的增加而增加。shbhl系统的其他特性，如隐环的长度和键的强度，也会影响结果。该模型还深入了解了响应生理变化的机械行为的变化，例如胶原纤维的矿化程度和纤维间基质中的聚合物密度。该模型结果为仿生材料设计和人体骨折的多尺度建模提供了相关约束。
Sacrificial bonds and hidden length (SBHL) in structural molecules provide a mechanism for energy dissipation at the nanoscale. It is hypothesized that their presence leads to greater fracture toughness than what is observed in materials without such features. Here, we investigate this hypothesis using a simplified model of a mineralized collagen fibril sliding on a polymeric interface with SBHL systems. A 1D coarse-grained nonlinear spring-mass system is used to model the fibril. Rate-and-displacement constitutive equations are used to describe the mechanical properties of the polymeric system. The model quantifies how the interface toughness increases as a function of polymer density and number of sacrificial bonds. Other characteristics of the SBHL system, such as the length of hidden loops and the strength of the bonds, are found to influence the results. The model also gives insight into the variations in the mechanical behavior in response to physiological changes, such as the degree of mineralization of the collagen fibril and polymer density in the interfibrillar matrix. The model results provide constraints relevant for bio-mimetic material design and multiscale modeling of fracture in human bone.