Mechanical behavior of human cortical bone in cycles of advancing tensile strain for two age groups
Mechanical behavior of human cortical bone in cycles of advancing tensile strain for two age groups
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DOI：
10.1002/jbm.a.31974
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发表时间：
2009-05-01
影响因子：
4.9
通讯作者：
Wang, Xiaodu
中科院分区：
文献类型：
--
作者：
Nyman, Jeffry S.;Roy, Anuradha;Wang, Xiaodu
骨的屈服后能量耗散能力随着年龄的增长而降低。为了获得这种变化的原因的信息，我们研究了与年龄相关的人类尸体骨的力学行为的变化作为渐进变形的函数。在这项研究中，拉伸标本从tibial 9中年和8老年人供体加载，直到失败的增量和循环（加载-停留-卸载-停留-重新加载）计划。在每个加载循环中，在增量应变下测定弹性模量、最大应力、永久应变、应力松弛、永久应变能、弹性释放应变能和滞后能。与以前的工作类似，本研究的结果也表明，老年人的骨在低得多的应变相比，中年骨失败。然而，除了老年骨的过早失效外，两个年龄组之间的骨力学行为没有显著差异。屈服后，骨的能量耗散和永久应变随应变的增加呈线性增加，而模量损失和应力松弛随应变的增加呈非线性变化。此外，应力松弛倾向于在1%时达到峰值，应变超过该值，很少有老年骨样本存活。这项研究表明，在骨的破坏机制不同的变形，和老化影响后屈服机制，从而引起与年龄相关的差异，在骨的力学性能，特别是组织的能量耗散能力。(C)2008 Wiley Periodicals，Inc. J Biomed Mater Res 89A：521-529，2009
The capacity of bone for post-yield energy dissipation decreases with age. To gain information on the causes of such a change, we examined age-related changes in the mechanical behavior of human cadaveric bone as a function of progressive deformation. In this study, tensile specimens from tibiae of nine middle aged and eight elderly donors were loaded till failure in an incremental and cyclic (load-dwell-unload-dwell-reload) scheme. The elastic modulus, maximum stress, permanent strain, stress relaxation, permanent strain energy, elastic release strain energy, and hysteresis energy were determined in each loading cycle at incremental strains. Similar with previous work, the results of the present study also indicated that elderly bone failed at much lower strains compared to middle aged bone. However, no significant differences in the mechanical behavior of bone were observed between the two age groups except for the premature failure of elderly bone. After yielding, the energy dissipation and permanent strain of bone appeared to linearly increase with increasing strain applied, while nonlinear changes occurred in the modulus loss and stress relaxation with increasing strain. Moreover, stress relaxation tended to peak at 1%, strain beyond which few elderly bone specimens Survived. This study suggests that damaging mechanisms in bone vary with deformation, and aging affects the post-yield mechanisms, thus giving rise to the age-related differences in the mechanical properties of bone, especially the capacity of the tissue for energy dissipation. (C) 2008 Wiley Periodicals, Inc. J Biomed Mater Res 89A: 521-529, 2009