组合腔型吸声覆盖层的声学特性分析

采用波导有限元方法分析了组合腔型吸声覆盖层单元的轴向波传播和损耗特性，并结合传递矩阵建立了该结构覆盖层声学特性的分析模型.以组合型圆台空腔吸声覆盖层为例，分别从波型转换和轴向波传播特性的角度分析了不同大小的空腔嵌入改变吸声覆盖层声学特性的规律.结果表明，随着大腔嵌入比例的增加，吸声系数的峰值频率逐渐向低频偏移，改善了低频吸声性能.

Acoustic Performance of Sound Absorption Coating Containing Composite Cavities

Using the waveguide finite element method, the propagation and the attenuation curves of the axial wave in the sound absorption coating which contains periodic composite cavities were obtained. Besides, the analytical approach of the acoustic performance of sound absorption coating was given together using the transfer matrix. Taking the sound absorption coating which contains periodic conical cavities as an example, the effect of cavity size on the acoustic performance was discussed both by the wave-mode transformation phenomenon and by the axial wave propagating characteristics respectively. Theerical results show that the peak absorption coefficient is shifted to the lower frequency as the proportion of bigger cavities in the composite coating increases.