A method for measuring linearly viscoelastic properties of human tympanic membrane using nanoindentation
A method for measuring linearly viscoelastic properties of human tympanic membrane using nanoindentation
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DOI：
10.1115/1.2838034
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发表时间：
2008-02-01
影响因子：
1.7
通讯作者：
Lu, Hongbing
中科院分区：
文献类型：
--
作者：
Huang, Gang;Daphalapurkar, Nitin P.;Lu, Hongbing
建立了一种粘弹性纳米压痕技术，用于测量人鼓膜（M）的面内和厚度方向的粘弹性。为了测量平面内杨氏松弛模量，将TM样品夹在圆孔上，并使用纳米压头尖端在TM样品的中心处施加集中力。在这种设置中，可以考虑主要由于面内刚度的纳米压痕位移的阻力。的.利用得到的载荷-位移曲线，沿着用有限元分析确定TM的面内粘弹性。为了测量杨氏松弛模量在整个厚度（平面外）方向，TM样品放置在一个相对刚性的固体基板和纳米压痕上的样品表面上。在后一种设置中，对纳米压痕位移的阻力主要是由于平面外刚度而产生的。以这种方式获得的载荷位移曲线用于使用适合于粘弹性材料的方法确定面外松弛模量。从我们的样品测试中，我们获得了类似于17.4 MPa和类似于19的面内模量的稳态值。TM样本的后部和前部分别为0 MPa，后部和前部TM样本的贯穿厚度模量值均类似于60 MPa。使用这种技术，可以确定整个TM上不同位置的局部面外粘弹性模量，并且可以确定TM不同象限的面内特性。
A viscoelastic nanoindentation technique was developed to measure both in-plane and through-thickness viscoelastic properties of human tympanic membrane (M). For measurement of in-plane Young's relaxation modulus, the TM sample was clamped on a circular hole and a nanoindenter tip was used to apply a concentrated force at the center of the TM sample. In this setup, the resistance to nanoindentation displacement can be considered due primarily to the in-plane stiffness. The. load-displacement curve obtained was used along with finite element analysis to determine the in-plane viscoelastic properties of TM. For measurements of Young's relaxation modulus in the through-thickness (out-of plane) direction, the TM sample was placed on a relatively rigid solid substrate and nanoindentation was made on the sample surface. In this latter setup, the resistance to nanoindentation displacement arises primarily due to out-of-plane stiffness. The load displacement curve obtained in this manner was used to determine the out-of-plane relaxation modulus using the method appropriate for viscoelastic materials. From our sample tests, we obtained the steady-state values for in-plane moduli as similar to 17.4 MPa and similar to 19. 0 MPa for posterior and anterior portions of TM samples, respectively, and the value for through-thickness modulus as similar to 60 MPa for both posterior and anterior TM samples. Using this technique, the local out-of-plane viscoelastic modulus can be determined for different locations over the entire TM, and the in-plane properties can be determined for different quadrants of the TM.