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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 regular octagonal hole-shaped local resonant phononic crystal structure is proposed. The bandgap generation mechanism, the influence factors of the band gap width and the sound insulation characteristics of the structure are analyzed by the finite element method. The results show that the resonant frequency is caused by the coupling between the local resonance element and the elastic wave. The coupling degree directly affects the band gap width and the attenuation speed of the elastic wave, thus affecting the sound insulation characteristics. The sound insulation amount depends on the regular octagonal porous core and The structural characteristics of the coating parameters. Increasing the mass of the core, reducing the side length of the regular octagonal frame, reducing the elastic modulus of the coating and increasing the density of the coating increase the bandgap width and the amount of sound insulation at the first noise peak , While the first noise peak moves to low frequencies. It shows that the sound insulation effect can be achieved by optimizing the structural parameters. It is of important theoretical significance to reduce noise in the low frequency band of a large military aircraft cabin.