Rohani S Alireza, Ghomashchi Soroush, Agrawal Sumit K, Ladak Hanif M
Biomedical Engineering Graduate Program, Western University, London, Ontario, Canada.
Department of Medical Biophysics, Western University, London, Ontario, Canada.
Hear Res. 2017 Mar;345:69-78. doi: 10.1016/j.heares.2017.01.002. Epub 2017 Jan 10.
Finite-element models of the tympanic membrane are sensitive to the Young's modulus of the pars tensa. The aim of this work is to estimate the Young's modulus under a different experimental paradigm than currently used on the human tympanic membrane. These additional values could potentially be used by the auditory biomechanics community for building consensus. The Young's modulus of the human pars tensa was estimated through inverse finite-element modelling of an in-situ pressurization experiment. The experiments were performed on three specimens with a custom-built pressurization unit at a quasi-static pressure of 500 Pa. The shape of each tympanic membrane before and after pressurization was recorded using a Fourier transform profilometer. The samples were also imaged using micro-computed tomography to create sample-specific finite-element models. For each sample, the Young's modulus was then estimated by numerically optimizing its value in the finite-element model so simulated pressurized shapes matched experimental data. The estimated Young's modulus values were 2.2 MPa, 2.4 MPa and 2.0 MPa, and are similar to estimates obtained using in-situ single-point indentation testing. The estimates were obtained under the assumptions that the pars tensa is linearly elastic, uniform, isotropic with a thickness of 110 μm, and the estimates are limited to quasi-static loading. Estimates of pars tensa Young's modulus are sensitive to its thickness and inclusion of the manubrial fold. However, they do not appear to be sensitive to optimization initialization, height measurement error, pars flaccida Young's modulus, and tympanic membrane element type (shell versus solid).
鼓膜的有限元模型对紧张部的杨氏模量很敏感。这项工作的目的是在一种与目前用于人体鼓膜的实验范式不同的情况下估计杨氏模量。这些额外的值可能会被听觉生物力学领域用于达成共识。通过对原位加压实验进行逆有限元建模来估计人体紧张部的杨氏模量。实验是使用定制的加压装置在500 Pa的准静态压力下对三个标本进行的。使用傅里叶变换轮廓仪记录每个鼓膜在加压前后的形状。还使用微型计算机断层扫描对样本进行成像，以创建特定于样本的有限元模型。对于每个样本，然后通过在有限元模型中对其值进行数值优化来估计杨氏模量，以使模拟的加压形状与实验数据相匹配。估计得到的杨氏模量值分别为2.2兆帕、2.4兆帕和2.0兆帕，与使用原位单点压痕测试获得的估计值相似。这些估计值是在以下假设下获得的：紧张部是线弹性的、均匀的、各向同性的，厚度为110微米，并且这些估计仅限于准静态加载。紧张部杨氏模量的估计值对其厚度和锤骨襞的包含情况很敏感。然而，它们似乎对优化初始化、高度测量误差、松弛部杨氏模量和鼓膜单元类型（壳单元与实体单元）不敏感。
