School of Aerospace and Mechanical Engineering, University of Oklahoma, Norman, OK, 73019, USA.
Ann Biomed Eng. 2017 Oct;45(10):2383-2394. doi: 10.1007/s10439-017-1870-0. Epub 2017 Jun 20.
Blast overpressure causes dynamic damage to middle ear components, and tympanic membrane (TM) rupture is the most frequent middle ear injury. However, it is unclear how the blast waves change mechanical properties of the TM and affect sound transmission through the ear. This paper reports the current study on dynamic properties of the TM after exposure to blast waves by using acoustic loading and laser Doppler vibrometry (LDV). The TM specimens were prepared from human temporal bones following exposures to blast overpressure. Vibration of the TM specimen induced by acoustic loading was measured by LDV over a frequency range of 200-8000 Hz. An inverse-problem solving method with finite element modeling was used to determine the complex modulus of the TM specimen. The post-blast storage modulus ranged from 23.1 to 26.9 MPa, and loss modulus ranged from 0.09 to 3.78 MPa as frequency increased from 200 to 8000 Hz. Compared to the complex modulus of normal TM reported in the literature, the post-blast storage and loss modulus decreased significantly across the frequency range. The scanning electron microscopy (SEM) images of the post-blast TM samples showed microstructural changes of the tissue, which explained the alteration of mechanical properties of the TM samples.
爆炸超压会对中耳结构造成动态损伤，而鼓膜（TM）破裂是最常见的中耳损伤。然而，目前尚不清楚爆炸波如何改变 TM 的力学性能以及如何影响声音通过耳朵的传播。本文通过声加载和激光多普勒测振（LDV）研究了爆炸波作用后 TM 的动态特性。TM 标本取自人类颞骨，在暴露于爆炸超压后进行制备。通过 LDV 测量 TM 标本在 200-8000 Hz 频率范围内的声加载诱导振动。采用反问题求解方法结合有限元建模来确定 TM 标本的复模量。爆炸后的储存模量范围为 23.1-26.9 MPa，损耗模量范围为 0.09-3.78 MPa，频率从 200 Hz 增加到 8000 Hz。与文献中报道的正常 TM 的复模量相比，爆炸后储存和损耗模量在整个频率范围内显著降低。爆炸后 TM 样本的扫描电子显微镜（SEM）图像显示了组织的微观结构变化，这解释了 TM 样本力学性能的改变。
