亥姆霍兹共振腔复合结构的吸声特性

Research on acoustic characteristics of Helmholtz resonator composite structure

针对由亥姆霍兹共振腔构成的声学结构,研究了在结构尺寸不变的约束下,有效提升吸声性能的方法。首先,基于声电类比,设计了单腔亥姆霍兹共振器;然后,对单腔进行非均匀分割,形成具有不同腔深的多个亥姆霍兹共振腔,构造多腔并联结构,并建立计算吸声系数的数学模型;接着,在多腔并联结构中添加多孔吸声材料,研究材料厚度对吸声性能的影响;最后,用微穿孔板替代多孔材料,构造亥姆霍兹共振腔微穿孔板复合结构,结合微穿孔板理论,研究结构的吸声性能。结果表明,通过对单腔进行非均匀分割,构造多腔并联结构,能显著提高吸声性能,但随着腔体个数的增加,低频截止频率有向高频偏移的趋势;在多腔并联结构底部添加多孔吸声材料,对吸声性能的提升效果十分有限;在多腔并联结构中布置微穿孔板,能显著拓宽有效吸声带宽,并提高整体吸声系数;结合多腔并联结构的设计和布置微穿孔板,能实现结构吸声性能的大幅提高,且随着并联腔数的增加,吸声性能提升效果更明显,吸声系数曲线更平滑。

Under the constraint of constant structure sizes of Helmholtz resonator composite structure,a method that can effectively improve the acoustic absorption performance of the structure is studied.First,based on the acoustoelectric analogy,a single cavity Helmholtz resonator is designed.Second,the single cavity is divided unevenly into multiple cavities with different depths to form a composite structure composed of multiple Helmholtz resonators,and a mathematical model is established to calculate its sound absorption coefficient.Then,porous materials are added to the cavities of the composite structure,and the influence of the material thickness on the sound absorption coefficient is analyzed.Finally,in order to obtain good acoustic absorption performances,micro-perforated plates are utilized to replace porous materials in the composite structure.The results show that,the acoustic absorption performance can be significantly improved by non-uniform division of a single-cavity,however,with the increase of the number of cavity,the low cutoff frequency tends to the high frequency;the effect of porous materials on the acoustic absorption performance is very limited;the arrangement of micro-perforated plates in the cavities of the composite structure can greatly broaden the effective sound absorption bandwidth and increase the overall sound absorption coefficient,and with the increase of the number of parallel chambers,the improvement effect of acoustic absorption performance is more obvious,and the sound absorption coefficient curve is smoother.