粘弹性本构对人耳动力学特性影响的数值研究

田佳彬1，饶柱石1，塔娜1，许立富1，黄新生2

(1.上海交通大学振动、冲击噪声研究所 机械系统与振动国家重点实验室，上海200240；2.复旦大学附属中山医院，上海200032)

摘要：为分析中耳软组织粘弹性材料特性对人耳系统动力学特性影响，建立包括外耳道、中耳及耳蜗的整耳有限元模型。外耳道及中耳模型用微CT扫描与逆向成型技术建立，耳蜗采用双腔导管形式简化模型。基于该模型，中耳部分软组织材料属性采用线性粘弹性，以表征动态分析中能量损耗。在外耳道施加90 dB SPL声压模拟声激励，并在计算中考虑外耳道气体、中耳固体及耳蜗流体多场耦合作用。中耳结构响应包括鼓膜脐部与镫骨底板位移及镫骨底板速度传递函数，耳蜗流体压力响应用于计算中耳压力增益、耳蜗输入声阻抗及压力逆向传递函数。结果表明，考虑粘弹性后，人耳系统动态响应参数较线弹性有一定程度改善，尤其在高频段提升较明显，与实验测量数据匹配效果更好。

关键词：粘弹性；动态能耗；耳蜗；动力学建模；多场耦合；有限元分析

中图分类号:R318.01文献标志码：A

Numerical analysis on the effects of viscoelastic constitutive relation on dynamic characteristics of human ear

TIANJia-bin1,RAOZhu-shi1,TANa1,XULi-fu1,HUANGXin-sheng2(1. Institute of Vibration, Shock and Noise, State Key Laboratory of Mechanical System and Vibration,Shanghai Jiao Tong University, Shanghai 200240, China; 2. Zhongshan Hospital A?liated to Fudan University, Shanghai 200032, China)

Abstract:To analyze the effects of viscoelastic properties of middle ear soft tissues on the dynamic characteristics of human ear system, a finite element (FE) model of the human ear consisting of the external ear canal, middle ear and cochlea was developed. The geometric configuration of the external ear canal and middle ear was constructed via micro-CT scanning and reverse engineering technology, and the cochlea was simplified as an uncoiled, two-chambered and fluid-filled duct. The viscoelastic material effect was introduced into the behaviors of middle ear soft tissues to represent the energy dissipation in dynamic analysis. A multiphysics coupled analysis was conducted on the model in which the coupling effects among the air in the ear canal, the fluid in the cochlea and the middle ear structures were concerned. Then a sound pressure of 90 dB SPL was applied on the ear canal to simulate the sound stimulus on normal human ear. Middle ear structural responses such as movements of the tympanic membrane and stapes footplate in response to the sound stimulus were derived by this model. Meanwhile, based on calculating the pressure of the fluid in the cochlea, the sound pressure gain across the middle ear, the cochlear input impedance and the reverse pressure transfer function of cochlea were also obtained. The results show that taking into account the viscoelastic properties of middle ear soft tissues can improve the dynamic responses of the human ear system as compared with the results of a linear elastic model, especially at the high-frequency range. The better agreements between the model results and the experimental data in the literature illustrate the necessity of considering viscoelasticity for dynamic modeling of human ear.

Key words:viscoelasticity; dynamic energy dissipation; cochlea; dynamic modeling; multiphysics coupling; finite element analysis

人耳系统主要由耳廓、外耳道、中耳及耳蜗构成。该系统具有复杂几何形态、超微型结构特征及非同质材料特性，且在正常生理过程中伴随声固耦合、流固耦合等复杂机理。基于此，采用有限单元法建立人耳数值模型已成为人耳生物力学研究的重要方法[1]。

中耳声传导模型主要用于模拟声音经外耳道、鼓膜、中耳听骨链至镫骨底板的传递机制[1-2]，其与耳蜗的耦合模型则可用于分析耳蜗内部淋巴液的压力响应及基底膜沿长度方向位移分布[3]等特性。……