Zhang Jing, Tian Jiabin, Ta Na, Huang Xinsheng, Rao Zhushi
Institute of Vibration, Shock and Noise, State Key Laboratory of Mechanical System and Vibration, Shanghai Jiao Tong University, Shanghai, China.
Department of Otorhinolaryngology-Head and Neck Surgery, Shanghai Zhongshan Hospital Affiliated to Fudan University, Shanghai, China.
Proc Inst Mech Eng H. 2016 Aug;230(8):784-94. doi: 10.1177/0954411916652923. Epub 2016 Jun 7.
Finite element method was employed in this study to analyze the change in performance of implantable hearing devices due to the consideration of soft tissues' viscoelasticity. An integrated finite element model of human ear including the external ear, middle ear and inner ear was first developed via reverse engineering and analyzed by acoustic-structure-fluid coupling. Viscoelastic properties of soft tissues in the middle ear were taken into consideration in this model. The model-derived dynamic responses including middle ear and cochlea functions showed a better agreement with experimental data at high frequencies above 3000 Hz than the Rayleigh-type damping. On this basis, a coupled finite element model consisting of the human ear and a piezoelectric actuator attached to the long process of incus was further constructed. Based on the electromechanical coupling analysis, equivalent sound pressure and power consumption of the actuator corresponding to viscoelasticity and Rayleigh damping were calculated using this model. The analytical results showed that the implant performance of the actuator evaluated using a finite element model considering viscoelastic properties gives a lower output above about 3 kHz than does Rayleigh damping model. Finite element model considering viscoelastic properties was more accurate to numerically evaluate implantable hearing devices.
本研究采用有限元方法，分析考虑软组织粘弹性时可植入式听力设备性能的变化。首先通过逆向工程建立了包含外耳、中耳和内耳的人耳集成有限元模型，并通过声-结构-流体耦合进行分析。该模型考虑了中耳软组织的粘弹性。模型推导得到的包括中耳和耳蜗功能的动态响应在高于3000Hz的高频下比瑞利型阻尼与实验数据具有更好的一致性。在此基础上，进一步构建了由人耳和附着在砧骨长突上的压电致动器组成的耦合有限元模型。基于机电耦合分析，使用该模型计算了与粘弹性和瑞利阻尼相对应的致动器的等效声压和功耗。分析结果表明，使用考虑粘弹性的有限元模型评估的致动器植入性能在约3kHz以上的频率下输出低于瑞利阻尼模型。考虑粘弹性的有限元模型在数值评估可植入式听力设备方面更准确。
