基于局域共振型声子晶体在机舱内低频隔声特性

Low Frequency Sound Insulation Characteristics of the Locally Resonant Phononic Crystals in the Large Aircraft Cabin

提出了一种正八边形孔状局域共振声子晶体结构,通过有限元法分析了该结构的带隙产生机理、带隙宽度影响因素以及隔声特性。结果表明:共振频率是由局域共振单元与弹性波耦合作用的结果,耦合程度直接影响带隙宽度和弹性波衰减速度,进而影响隔声特性;隔声量取决于正八边形孔状芯体和包覆层的结构特性参数。增大芯体质量,减小正八变形框的边长,同时减小包覆层弹性模量和增大包覆层密度,则带隙宽度增大,第一隔声峰处的隔声量增大,同时第一隔声峰向低频移动。表明通过优化结构参数,可以达到良好的隔声效果,在大型军机舱室低频段降噪具有重要的理论意义。

A kind of the octagon ring local resonance phononic crystal structure was proposed. The band gap formation mechanisms, the width of band gap affect factors, and sound insulation characteristics were analyzed by a finite element method. It is found that the resonance frequency is the results of interaction between the local resonances and the elastic waves, and the bandwidth and the sound attenuation rate of elastic waves depend on the interaction strength and have an impact on the sound insulation characteristics. Moreover, the transmission loss is related to the parameter characteristics of the octagon ring core and capping layer materials. These results indicate that the increase of the mass core and the capping layer densit as well as the decrease of the octagon ring side length and the elastic modulus of the capping layer lead to the width of band-gap, the high transmission loss of the first peak of sound insulation and the first sound insulation peak shifting to low-frequency simultaneously. This result shows that the structure has a good sound insulation of characteristics by optimizing the structure parameters, which has a theoretical impact in the aircraft cabin.