新型Helmholtz型声子晶体的低频带隙及隔声特性  

Low-frequency bandgaps and sound isolation characteristics of a novel Helmholtz-type phononic crystal

作　　者：韩东海 张广军[1] 赵静波[1] 姚宏[1] Han Dong-Hai;Zhang Guang-Jun;Zhao Jing-Bo;Yao Hong(Fundamentals Department,Air Force Engineering University,Xi’an 710051,China)

机构地区：[1]空军工程大学基础部,西安710051

出　　处：《物理学报》2022年第11期203-211,共9页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:11504429)资助的课题.

摘　　要：为了解决军用飞机舱室内产生的低频噪声问题,构建了一种新型的Helmholtz型二维声子晶体,该结构采用迷宫型开口通道,并在结构加入了刚性振子.研究发现,该结构在晶格常数为62 mm条件下,将第一低频带隙的下限降至15 Hz左右,且在100 Hz频率左右形成一条宽度为93 Hz的带隙宽带,表现出较好的低频隔声特性.首先,通过振型及声压场分析了其带隙成因,采用“力-声类比”的方法建立了该结构的等效模型,最后利用有限元法和传递矩阵法对第一低频的带隙范围进行了计算,两种方法所得结果基本相符;其次,通过有限元法探究了晶格常数、空气通道长度及振子材料等结构参数对低频带隙的影响.研究表明,增加开口通道长度和晶格常数都会降低第一带隙下限,增加振子材料密度能够有效降低第二带隙的上下限,进一步揭示了该结构带隙形成的实质,验证了等效模型的准确性.该研究为低频噪声控制方面提供了一定的理论支持,为低频声子晶体的设计提供了新的思路.In recent years,the vibration and noise reduction performance of military aircraft has become an important index to measure its performance.In order to solve the problem of low-frequency noise generated by military aircraft,a novel Helmholtz two-dimensional phononic crystal is constructed in this paper.The structure adopts maze-shaped air channel and adds rigid oscillators.On condition that the lattice constant is 62 mm,the lower limit of the first band gap is reduced to about 15 Hz.The structure has four complete band gaps in a range of 0-500 Hz,specifically,they being 15.223-17.464 Hz,107.46-200.68 Hz,231.18-310.68 Hz,and 341.14-404.49 Hz.In addition,the sound reduction index of the structure reaches 25 dB at 15 Hz,and two peaks higher than 150 dB appear at about 107 Hz and 231 Hz.which shows distinct sound insulation capability in the low-frequency range.It has engineering significance in controlling the low-frequency noise in the aircraft cabin.The cause of the band gap is explored by analyzing the vibration mode and sound pressure field.The“spring-oscillator”of the structure model is established by the method of“Mechanical-acoustic analogy”.The finite element method and transfer matrix method are used to calculate the upper limit and the lower limit of the first band gap.It is shown that for the first gap of the structure,the results obtained by the two methods are similar,which indicates the correctness of the model hypothesis.Secondly,the effects of structural parameters such as the lattice constant,the length of the air channel and the oscillator material on the first band gap are investigated by finite element method and equivalent model method.It is obtained that the increase of the length of air channel and lattice constant will reduce the lower limit of the first band gap,with other structural parameters remaining unchanged.Moreover,the increase of the density of the oscillator material can effectively reduce the upper limit and lower limit of the second band gap,which further reveals the esse

关 键 词：Helmholtz共振腔 声子晶体 低频带隙 隔声降噪 

分 类 号：O735[理学—晶体学]