中文摘要：

研究一种含两个对称三角形腔的波导管中宽频带低频隔声效应.波导管的隔声频带下限与带宽分别可达到140Hz和2900Hz,且所调控声波最大波长是三角形腔的尺寸13.6倍.这种隔声效应源于三角形腔截面积与波导管宽度的差异而引起的交界面上的高声反射率.在此基础上,研究波导管的结构参数（如波导管的宽度、三角形腔的底边长度与高度）及不同类型的腔（Helmholtz腔、矩形腔与直角三角形腔）对低频隔声效果的影响.结果表明,三角形腔的截面积和波导管宽度的差异与低频隔声效果密切相关.此外,由于对结构的本征模式的抑制作用,直角三角形腔所对应的低频隔声频带最宽.所提出的结构具有高隔声、宽频带、结构简单易实现等优点,在声学领域具着一定的潜在应用价值.

英文摘要：

We report a broadband sound insulation effect through a waveguide with two triangle cavities.The lower cutoff frequency and bandwidth of the sound insulation could reach about 140 Hz and 2900 Hz,respectively,and the length of the triangle cavity is aboutλ/13.6.This phenomenon arises from high acoustic reflectance owing to the difference between the cross-sectional areas of the waveguide and triangle cavities.In addition,we also investigate the influences of the parameters of waveguide,such as the wide of the waveguide,the base and height of both triangle cavities,on the characteristics of the sound insulation.Besides,the sound insulation in the waveguide with other types of cavities（Helmholtz cavities,rectangle cavities,and right triangle cavities）on the sound insulation is also discussed in detail.The results show that the performance of sound insulation is closely related to the difference between the cross-sectional areas of the waveguide and triangle cavities,and the wider bandwidth of the sound insulation is obtained by using the right triangle cavities owing to the inhibition of the eigen modes.The design has the advantages of high sound insulation,broad bandwidth,and simple structure as well as being easy to be achieved.