TRABECULAR BONE EXHIBITS FULLY LINEAR ELASTIC BEHAVIOR AND YIELDS AT LOW STRAINS
TRABECULAR BONE EXHIBITS FULLY LINEAR ELASTIC BEHAVIOR AND YIELDS AT LOW STRAINS
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DOI：
10.1016/0021-9290(94)90053-1
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发表时间：
1994-09-01
影响因子：
2.4
通讯作者：
HAYES, WC
中科院分区：
文献类型：
--
作者：
KEAVENY, TM;GUO, XE;HAYES, WC
为了减少传统的骨小梁压缩测试中的实验伪影，我们对牛胫骨松质骨进行了体外力学测试，以获得对弹性行为和屈服行为的准确描述。小截面圆柱形试件经过8次拉伸-压缩(+/-0.5%应变)循环，然后在拉伸(n=15)或压缩(n=14)加载到破坏。我们发现，每个试件的屈服前行为都是完全线性的，这表明最初的非线性“脚趾”是一个实验伪影。对弹性模量的方差分析表明，预处理前拉伸和压缩弹性模量之间没有显著差异。然而，预处理组的拉伸和压缩模数平均分别降低了8.8%(p<；0.01)和5.3%(p<；0.01)，其中拉伸模数的降幅更大(p<；0.01)。这些轻微但显著的弹性模量下降表明，初始屈服涉及单个骨小梁的微结构损伤(而不是塑性滑移)，也表明(牛胫骨)小梁骨的拉伸和/或压缩屈服应变小于0.5%。平均拉伸强度约为平均压缩强度的70%，尽管这种强度差异可能受到预适应诱导的损伤的影响。综上所述，这些结果表明，松质骨和皮质骨的弹性行为和屈服行为之间存在着比先前假设更多的相似性。
Using a protocol designed to reduce experimental artifacts associated with the conventional compression test for trabecular bone, we performed in vitro mechanical testing on bovine tibial trabecular bone to obtain accurate descriptions of the elastic and yield behaviors. Reduced-section cylindrical specimens were preconditioned for eight tension-compression (+/-0.5% strain) cycles and then loaded to failure either in tension (n = 15) or compression (n = 14). We found that the pre-yield behavior for every specimen was fully linear, indicating that the initial nonlinear 'toe' is an experimental artifact. Analysis of variance on the moduli indicated that there was no significant difference between the tensile and compressive moduli before preconditioning. However, preconditioning decreased the tensile and compressive moduli on average by 8.8 % (p < 0.01) and 5.3 % (p < 0.01), respectively, with the decrease in tensile modulus being larger (p < 0.01). These small but significant decreases in modulus suggest that initial yielding involves microstructural damage (as opposed to plastic slip) of individual trabeculae and also indicate that the tensile and/or the compressive yield strain of(bovine tibial) trabecular bone is less than 0.5%. The mean tensile strength was approximately 70% of the mean compressive strength, although this difference in strengths may have been affected by the preconditioning-induced damage. Taken together, these results suggest that there are more similarities between the elastic and yield behaviors of trabecular and cortical bone than had been assumed previously.