基于Helmholtz共振腔阵列的声学超材料研究

为有效控制特定频段的噪声，基于Helmholtz共振腔阵列，通过Helmholtz共振腔短管位置的控制，设计了一种新型的局域共振型声学超材料。利用COMSOL Multiphysics软件求得新型声学超材料的能带图和传递损失曲线，并与具有单一方向开口的Helmholtz共振腔阵列的传递损失曲线进行对比；同时，为分析新型声学超材料的带隙形成机理，求得了其在带隙频率范围内的声压分布云图。通过试验测试了新型声学超材料的吸声性能。结果表明：新型声学超材料的能带图中产生了2段较窄带隙和1段较宽带隙，在带隙频率范围内，声学超材料传递损失出现峰值；第1带隙和第2带隙较窄，原因是单个Helmholtz共振腔局域共振，声波能量消耗少；第3带隙较宽，原因是Helmholtz共振腔与其周期排列形成的外部波导联合共振吸声，消耗大量声波能量。试验测试结果与仿真计算结果较为吻合，新型声学超材料可有效控制1 300~1 500 Hz和1 500~2 000 Hz频率范围内的噪声。研究结果表明，所设计的新型局域共振型声学超材料可有效实现中低频减振降噪，为声学超材料在中低频的降噪控制研究提供了新的思路。

Research on acoustic metamaterial based on Helmholtz resonant cavity array

In order to effectively control the noise of specific frequency band, a new locally resonant acoustic metamaterial was designed based on Helmholtz resonant cavity array and by controlling the position of the Helmholtz resonant cavity short tube. The energy band graph and transfer loss curve of the new acoustic metamaterial were obtained by using COMSOL Multiphysics software, and the transfer loss curve was compared with that of Helmholtz resonant cavity array with a single directional opening.Meanwhile, in order to analyze the band gap formation mechanism of the new acoustic metamaterial, the acoustic pressure distribution nephogram in the band gap frequency range was obtained. The sound absorption performance of the new acoustic metamaterial was tested by experiments. The results showed that there were two relatively narrow band gaps and one relatively wide band gap in the band graph of the new acoustic metamaterial, and within the band gap frequency range, the transfer loss of the acoustic metamaterial peaked. The first band gap and the second band gap were relatively narrow, which was due to the local resonance of a single Helmholtz resonant resonator and less acoustic energy consumption. The third band gap was relatively wide, because the external waveguide formed by the Helmholtz resonance cavity and its periodic arrangement resonated and absorbed sound, which consumed a lot of acoustic energy.The experimental result was in good agreement with the simulation result. The new acoustic metamaterial can effectively control the noise in the frequency range of 1 300-1 500 Hz and 1 500-2 000 Hz. The results show that the new locally resonant acoustic metamaterial designed can effectively reduce vibration and noise in the middle and low frequencies, which provides a new idea for the research of acoustic metamaterials on noise reduction control in the middle and low frequencies.