声子晶体的传输特性研究

Research of Propagation Characteristics in Phononic Crystals

为探究声子晶体的声波控制机理,研究了声波在声子晶体中的传播行为.通过分析声波激励声子晶体元胞的局域共振响应特性,计算了局域共振型声子晶体的频率响应.运用comsol软件模拟线声源激励在声子晶体薄板后汇聚成点声源.基于光外差测量平台进行了声传输实验,测量汇聚点的声压,并利用NE564组成中心频率为40 MHz锁相环电路来解调声子晶体表面振动信息.运用Matlab处理数据得到声子晶体的频率响应函数,即声子晶体传输特性.实验结果表明,共振频率可以确定声子晶体带隙,减小包覆层橡胶的刚度以降低带隙频率.

In order to probe into the controlled mechanism of sound wave by phononic crystals,propaga-tion characteristics of sound waves in phononic crystals was studied.With the analysis of local resonance properties of the cell in phononic crystals by acoustic excitation,frequency response function of locally resonant phononic crystal was calculated.Comsol software was applied to simulate the linear sound source excitation wave through phononic crystals converged into point sound source behind the slabs. Based on the optical heterodyne measurement,sound transmission experiment was performed to measure the sound pressure of convergence point.NE564 was used to form the phase-locked loop circuit with the center frequency of 40MHz,which is applied to demodulate the vibration information of the phononic crystal surface.Finally,Matlab software was used to process the vibration data and the phononic crys-tals frequency response function,which was named the phononic crystals propagation properties.The experimental results show that the resonance frequency can determine the phononic band gap,reduce the stiffness of the rubber coating can decrease the frequency of band gap.