Sound absorption of a finite flexible micro-perforated panel backed by an air cavity
Sound absorption of a finite flexible micro-perforated panel backed by an air cavity
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DOI：
10.1016/j.jsv.2004.11.024
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发表时间：
2005-10
影响因子：
4.7
通讯作者：
Yiu-yin Lee;E. Lee;C. Ng
中科院分区：
文献类型：
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作者：
Yiu-yin Lee;E. Lee;C. Ng
微穿孔吸收器已经研究了几十年。在以往的一些实验结果中，由于柔性板的振动效应，在吸收系数曲线上发现了一个意想不到的峰值。本文详细研究了有限长柔性微穿孔板在空气腔作用下的吸声特性。微穿孔吸收器的吸收公式是基于经典板方程的模态分析解耦合声波方程。另一种方法来推导一个更简单的吸收公式也被开发。两个公式的预测结果非常接近，除了在平行于板表面的高阶结构模态和声学模态的共振频率处的预测结果。理论计算结果与实测结果吻合较好。研究结果表明：（1）由于板的振动效应可以耗散更多的能量，通过适当选择板厚、穿孔直径和穿孔间距等参数，相应的吸收峰可以拓宽微穿孔吸声体的吸收带宽，使得结构共振频率高于由穿孔引起的吸收峰值频率;（2）不同板模态形状的情况的比较没有显示出吸收性能的显著差异;结构阻尼效应可以提高结构共振频率与微穿孔效应峰值频率之间频率处的吸波性能，并降低结构共振的峰值吸收值。
Micro-perforated absorbers have been studied for decades. In the experimental results of some previous works, an unexpected peak due to the flexible panel vibration effect was found on the absorption coefficient curve. In this paper, the acoustic absorption of a finite flexible micro-perforated panel backed by an air cavity is studied in detail. The absorption formula that is developed for the micro-perforated absorber is based on the modal analysis solution of the classical plate equation coupled with the acoustic wave equation. Another approach to derive a simpler absorption formula is also developed. The predictions from the two formulas are very close, except for those at the resonant frequencies of the higher structural modes and acoustic modes parallel to the panel surface. The theoretical results show good agreement with the measurements. It can be concluded that (1) as the panel vibration effect can dissipate more energy, the corresponding absorption peaks can widen the absorption bandwidth of a micro-perforated absorber by appropriately selecting the parameters such as panel thickness, perforation diameter, and perforation spacing, etc., such that the structural resonant frequency is higher than the absorption peak frequency caused by the perforations; (2) the comparison of the cases of different panel mode shapes does not show a significant difference in the absorption performance; and (3) the structural damping effect can improve the absorption performance at the frequencies between the structural resonant frequencies and the peak frequency of the micro-perforation effect, and decrease the peak absorption values of the structural resonances.