基于准周期共鸣器阵列的声阻抗突变界面爆裂声抑制研究

Periodic Helmholtz resonators array has been found of extensive applications in different acoustic frequency ranges with different scale of geometries. For example, it is found to be a new class of metamaterials to realize the acoustic cloaking; it can be mounted in the train tunnel to suppress the acoustic shock wave formed in the tunnel due to the entrance of the high-speed trains; and it can be an effective noise control method based on the low-frequency wide forbidden-band resulted from the combination of the Bragg reflection and resonance under specific conditions. Based on these findings, this research aims at further understanding on the acoustic performance of the periodic and quasi-periodic Helmholtz resonators array by investigating the characteristics of its forbidden-band and the nonlinear sound propagation inside theoretically, numerically and experimentally. Moreover, this research will further seek the potential application of quasi-periodic Helmholtz resonators array on the suppression of bursting sound radiation from the acoustic impedance-mutation interface.

近年来，周期性Helmholtz共鸣器阵列已经被发现在不同的尺度上、不同频率范围内有着广泛的应用前景：如声隐形超材料设计、列车隧道口辐射声抑制及低频宽带无源噪声控制等。本项目以这些前期研究为基本背景，以声阻抗突变界面处的爆裂声问题为切入点，拟采用理论研究、数值模拟、实验验证相结合的方法，深入探讨周期性及准周期性共鸣器阵列的结构特性，重点对（准）周期性共鸣器阵列的禁带特征以及非线性波在该结构中的传播特性等问题展开研究；并在此基础性研究之上，进而探讨基于准周期性共鸣器阵列的声阻抗突变界面处爆裂声的抑制方法。

本项目在先前工作的基础上首先对共鸣器等声结构周期阵列进行进一步深入的研究，提出了基于目标禁带特征的共鸣器阵列系统参数优化方案，并系统分析了不同扰动类型的影响，进一步采取人为引入扰动来调节系统性能，提升周期阵列对于噪声的控制水平。以此为基础，项目进一步深入探讨在声阻抗突变界面处的产生爆裂声在管道中的传播的抑制方法。研究发现，通过恰当引入对周期性共鸣器个体之间的扰动，实现的人为调制后的准周期性共鸣器阵列，能够更有效的抑制该爆裂声问题。随着研究的不断深入，研究重心由原来的纯周期性结构--周期性带扰动结构--声学结构规律性变化形成的结构阵列逐步转移，研究发现这种人工制成的阻抗分布阵列有着非常独特的调制反射声场分布的特性。以此为基础，我们将该结构应用在道路旁声屏障，临近道路高层建筑阳台上，通过设计阵列的阻抗分布特征，来有效控制反射声场，进而大幅度改善了声屏障和临街阳台的声学性能。