Mechanisms of uniformity of yield strains for trabecular bone
Mechanisms of uniformity of yield strains for trabecular bone
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DOI：
10.1016/j.jbiomech.2004.02.045
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发表时间：
2004-11-01
影响因子：
2.4
通讯作者：
Keaveny, TM
中科院分区：
文献类型：
--
作者：
Bayraktar, HH;Keaveny, TM
特定解剖部位内小梁骨屈服应变的变化仅是弹性模量和强度存在的实质性变化的一小部分，但这种均匀性的来源尚不清楚。我们的目标是研究潜在的机制，通过使用高分辨率，材料非线性有限元模型的12人股骨颈松质骨标本。用于获得拉伸和压缩下表观屈服应变的有限元模型假设所有样本的组织水平屈服应变相同。因此，模型预测与实验数据的比较使我们能够将体积分数和结构的组合作用与组织材料特性的作用隔离开来。结果表明，拉伸和压缩载荷，自然变化的体积分数和架构产生的变异系数可以忽略不计（小于3%）的表观屈服应变。组织水平的应变分析表明，虽然弯曲的个别小梁只发挥了很小的作用，在表观弹性行为，这种弯曲和组织水平的强度不对称的综合效应产生明显的水平失败应变压缩，比那些在组织水平低14%。相比之下，组织和表观水平的屈服应变是等同的拉伸载荷。我们的结论是，表观屈服应变的均匀性主要是高度定向结构的结果，该结构最大限度地减少了弯曲。大多数确实发生的变异是组织水平产量菌株的不均匀性的结果。(C)2004爱思唯尔有限公司保留所有权利。
Variations in yield strains for trabecular bone within a specific anatomic site are only a small fraction of the substantial variations that exist for elastic modulus and strength, and yet the source of this uniformity is not known. Our goal was to investigate the underlying mechanisms by using high-resolution, materially nonlinear finite element models of 12 human femoral neck trabecular bone specimens. The finite element models, used to obtain apparent yield strains in both tension and compression, assumed that the tissue-level yield strains were the same across all specimens. Comparison of the model predictions with the experimental data therefore enabled us to isolate the combined roles of volume fraction and architecture from the role of tissue material properties. Results indicated that, for both tensile and compressive loading, natural variations in volume fraction and architecture produced a negligible coefficient of variation (less than 3%) in apparent yield strains. Analysis of tissue-level strains showed that while bending of individual trabeculae played only a minor role in the apparent elastic behavior, the combined effects of this bending and tissue-level strength asymmetry produced apparent-level failure strains in compression that were 14% lower than those at the tissue level. By contrast, tissue and apparent-level yield strains were equivalent for tensile loading. We conclude that the uniformity of apparent yield strains is primarily the result of the highly oriented architecture that minimizes bending. Most of the variation that does occur is the result of the non-uniformity of the tissue-level yield strains. (C) 2004 Elsevier Ltd. All rights reserved.