Effect of indenter size on elastic modulus of cartilage measured by indentation
Effect of indenter size on elastic modulus of cartilage measured by indentation
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DOI：
10.1115/1.2768110
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发表时间：
2007-10-01
影响因子：
1.7
通讯作者：
Lewis, Jack L.
中科院分区：
文献类型：
--
作者：
Simha, Narendra K.;Jin, Hui;Lewis, Jack L.
我们的初步压痕实验表明，小鼠胫骨软骨的平衡弹性模量随着压头尺寸的减小而增加：端部直径为15 μ m和90 μ m的平头60度锥形尖端分别给出1.50 +/- 0.82 MPa（平均标准差）和0.55 +/- 0.11 MPa（p < 0.01）。本文的目的是确定是否依赖于尖端尺寸是一个固有的特征的平衡弹性模量的软骨压痕测量。由于非压痕测试的模量值无法用于小鼠软骨的比较，因此使用牛软骨。采用末端直径为5 μ m ~ 4 mm的平头圆锥形或圆柱形针尖测量牛髌骨软骨的平衡弹性模量。使用了相同的头端。以测试聚氨酯橡胶进行比较。牛髌骨软骨的平衡模量随着尖端尺寸的减小而单调增加。从2 mm和4 mm尖端获得的模量（0.63 +/- 0.21 MPa）与文献中报道的值一致;然而，由90 μ m尖端测得的模量比从1000 μ m尖端获得的值大2.5倍以上。相反，使用相同的5 μ m-4 mm尖端获得的聚氨酯橡胶的弹性模量与尖端尺寸无关。压痕法测得的牛髌软骨的平衡弹性模量与针尖尺寸有关。这似乎是软骨压痕的固有特征，可能是由于其不均匀的结构。
Our preliminary indentation experiments showed that the equilibrium elastic modulus of murine tibial cartilage increased with decreasing indenter size: flat-ended 60 deg conical tips with end diameters of 15 mu m and 90 mu m gave 1.50 +/- 0.82 MPa (mean standard deviation) and 0.55 +/- 0.11 MPa, respectively (p < 0.01). The goal of this paper is to determine if the dependence on tip size is an inherent feature of the equilibrium elastic modulus of cartilage as measured by indentation. Since modulus values from nonindentation tests are not available for comparison for murine cartilage, bovine cartilage was used. Flat-ended conical or cylindrical tips with end diameters ranging from 5 mu m to 4 mm were used to measure the equilibrium elastic modulus of bovine patellar cartilage. The same tips were used. to test urethane rubber for comparison. The equilibrium modulus of the bovine patellar cartilage increased monotonically with decreasing tip size. The modulus obtained from the 2 mm and 4 mm tips (0.63 +/- 0.21 MPa) agreed with values reported in the literature; however the modulus measured by the 90 mu m tip was over two and a half times larger than the value obtained from the 1000 mu m tip. In contrast, the elastic modulus of urethane rubber obtained using the same 5 mu m-4 mm tips was independent of tip size. The equilibrium elastic modulus of bovine patellar cartilage measured by indentation depends on tip size. This appears to be an inherent feature of indentation of cartilage, perhaps due to its inhomogeneous structure.