Age-related differences in post-yield damage in human cortical bone. Experiment and model
Age-related differences in post-yield damage in human cortical bone. Experiment and model
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DOI：
10.1016/0021-9290(96)84542-8
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发表时间：
1996-11-01
影响因子：
2.4
通讯作者：
Gibson, LJ
中科院分区：
文献类型：
--
作者：
Courtney, AC;Hayes, WC;Gibson, LJ
很少有定量比较皮质骨的力学测试行为和显微镜下的损伤证据的报道。在这项研究中，假设与年龄相关的人类皮质骨的机械性能的退化与微裂纹形式的损伤的增加进行了调查。初始模量和;屈服应力分别为6%（不显著）和10%（p = 0.05）低，从老年股骨标本比从年轻成人股骨标本。然而，两组均显示在加载至1%应变后模量降低34%。在骨水泥线和层间观察到平行于加载方向的微裂纹。有50%以上的裂纹在纵向截面的测试样本比对照组老年股骨，但是，有没有更多的裂纹在测试样本比对照组年轻的成年股骨。此外，对照组中的裂纹数量是年轻成人股骨的两倍，老年股骨的试验样本中的裂纹数量是年轻成人股骨的三倍（p < 0.01）。开发了一个基于微观结构的模型，该模型支持力学试验结果，并表明损伤在约1500 μ m时开始发展。结果表明，由于存在更多的微裂纹，老年骨可能具有降低的机械性能，并且老年骨在给定的应变水平下更容易产生微裂纹。然而，力学测试数据表明，从年轻的成年股骨标本也持续某种形式的损伤作为一个结果的机械负荷，这需要进一步调查。版权所有（C）1996 Elsevier Science Ltd.
Very few quantitative comparisons between mechanical test behavior of cortical bone and microscopic evidence of damage have been reported. In this study, the hypothesis that age-related degradation of mechanical properties in human cortical bone is associated with increases in damage in the form of microcracks was investigated. The initial modulus and;yield stress were 6% (not significant) and 10% (p = 0.05) lower, respectively, in specimens from elderly femora than in specimens from young adult femora. However, both groups showed a 34% decrease in modulus after being loaded to 1% strain. Microcracks were observed in cement lines and between lamellae and were parallel to the loading direction. There were 50% more cracks in longitudinal sections of tested specimens than in controls from elderly femora; however, there were no more cracks in tested specimens than in controls from young adult femora. In addition, there were twice as many cracks in controls and three times as many cracks in tested specimens from elderly femora than in those from young adult femora (p < 0.01). A microstructurally based model was developed which supported the mechanical test results and indicated that damage began to develop at about 1500 mu epsilon. The results suggest that older bone may have reduced mechanical properties due to the presence of more microcracks, and that older bone is more susceptible to developing microcracks at a given strain level. However, the mechanical test data indicate that specimens from young adult femora also sustained some kind of damage as a result of mechanical loading, which requires further investigation. Copyright (C) 1996 Elsevier Science Ltd.