Sub-lamellar microcracking and roles of canaliculi in human cortical bone
Sub-lamellar microcracking and roles of canaliculi in human cortical bone
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DOI：
10.1016/j.actbio.2011.11.013
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发表时间：
2012-03-01
影响因子：
9.7
通讯作者：
Wang, Rizhi
中科院分区：
文献类型：
--
作者：
Ebacher, Vincent;Guy, Pierre;Wang, Rizhi
骨是一种坚韧的生物材料。人们普遍认为，骨的韧性来自于其独特的等级结构，这反过来又促进了骨折前的分布式微裂纹。然而，关于结构元素在微裂化过程中的详细作用的研究进展有限。本研究考察了压缩载荷作用下人皮质骨在板层和亚板层水平的结构与微裂纹的关系。激光扫描共聚焦显微镜显示，哈弗斯系统片层的局部结构和孔隙率对微裂纹的发展有明显的影响。特别是，横向压缩下裂纹的萌生和扩展与小管处的应力集中有关。后期的微裂纹表现为广泛的亚层状裂纹，形成交错的阴影图案，并规则地间隔0.5-1.7微米。裂纹的密度、大小和规律性表明，通过在矿化的胶原纤维束水平上控制裂纹，增强了非弹性变形能力。因此，本研究改进了目前对骨中非弹性变形和微裂纹本质的理解，并进一步表明，骨的抗骨折能力是通过在多个长度尺度上控制微裂纹来实现的。(C)2011 Acta Materialia Inc.由爱思唯尔有限公司出版。保留所有权利。
Bone is a tough biological material. It is generally accepted that bone's toughness arises from its unique hierarchical structure, which in turn facilitates distributed microcracking prior to fracture. Yet, there has been limited progress on the detailed roles of the structural elements in the microcracking process. The present study examines the structure-microcracking relations at the lamellar and sub-lamellar levels of human cortical bone subjected to compressive loading. Laser scanning confocal microscopy revealed a clear influence of the local structure and porosity of the Haversian systems' lamellae on microcrack development. In particular, crack initiation and growth under transverse compression were associated with stress concentration at canaliculi. Later stages of microcracking showed extensive sub-lamellar cracks forming cross-hatched patterns and regularly spaced 0.5-1.7 mu m apart. The density, size and regularity of the crack patterns suggest enhanced inelastic deformation capacity through cracking control at the level of mineralized collagen fibril bundles. The present study thus improves the current understanding of the nature of inelastic deformation and microcracking in bone and further suggests that bone's resistance to fracture is achieved through microcrack control at multiple length scales. (c) 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.