Micro and Nano Electro Mechanical System Laboratory, Northwestern Polytechnical University, Xi'an City, Shaanxi Province, 710072, China; E-Mails:
Sensors (Basel). 2009;9(7):5637-48. doi: 10.3390/s90705637. Epub 2009 Jul 15.
The parasitoid fly Ormia ochracea shows an astonishing localization ability with its tiny hearing organ. A novel MEMS biomimetic acoustic pressure gradient sensitive structure was designed and fabricated by mimicking the mechanically coupled tympana of the fly. Firstly, the analytic representation formulas of the resultant force and resultant moment of the incoming plane wave acting on the structure were derived. After that, structure modal analysis was performed and the results show that the structure has out-of-phase and in-phase vibration modes, and the corresponding eigenfrequency is decided by the stiffness of vertical torsional beam and horizontal beam respectively. Acoustic-structural coupled analysis was performed and the results show that phase difference and amplitude difference between the responses of the two square diaphragms of the sensitive structure are effectively enlarged through mechanical coupling beam. The phase difference and amplitude difference increase with increasing incident angle and can be used to distinguish the direction of sound arrival. At last, the fabrication process and results of the device is also presented.
寄生蝇 Ormia ochracea 凭借其微小的听觉器官表现出惊人的定位能力。通过模拟蝇类机械耦合的鼓膜，设计并制作了一种新颖的 MEMS 仿生声压梯度敏感结构。首先，推导出了作用于结构的入射平面波的合力和合力矩的解析表达式。然后，进行了结构模态分析，结果表明该结构具有反相和同相振动模式，相应的固有频率由垂直扭转梁和水平梁的刚度决定。进行了声-结构耦合分析，结果表明通过机械耦合梁有效地增大了敏感结构两个方形膜片响应之间的相位差和幅值差。相位差和幅值差随入射角的增加而增加，可用于区分声音到达的方向。最后，还介绍了该器件的制造工艺和结果。
