Enhancement of low-frequency sound absorption of microperforated panels by adding a mechanical impedance  

作　　者：ZHAO Xiaodan LI Xiao DING Rui 

机构地区：[1]School of Automobile and Traffic Engineering,Jiangsu University

出　　处：《Chinese Journal of Acoustics》2015年第1期27-36,共10页声学学报（英文版）

基　　金：supported by the Scientific Research Foundation for Senior Professional of Jiangsu University(11JDG096);the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions((2011)6)

摘　　要：In order to solve the bad low frequency sound absorption of the Micro-Perforated panel （MPP） absorber, mechanical impedance was introduced in the back of the MPP absorber to form a composite structure. According to the same particle vibration velocity on both sides of a plate, the mechanical impedance plate transfer matrix could be obtained. The units of the mechanical impedance, cavity and MPP were connected in series with the use of the transfer matrix method, thus creating the composite structure＇s theoretical calculation model. The qual- ity factor affecting absorption bandwidth was analyzed. Bandwidth is inversely proportional to the mechanical impedance plate mass. During the experiments, when at close to 400 Hz, the composite structure reached an absorption peak with a coefficient of above 0.8. Experimen- tal results concurred with theoretical calculations. Mechanical resonance is added based on the traditional MPP resonance sound absorption mechanism. Through this, the performance of low frequency sound absorption can be improved without increasing the thickness of the structure. The frequency band can be broadened by reducing the mechanical impedance plate mass and controlling its boundary-damping coefficient.In order to solve the bad low frequency sound absorption of the Micro-Perforated panel （MPP） absorber, mechanical impedance was introduced in the back of the MPP absorber to form a composite structure. According to the same particle vibration velocity on both sides of a plate, the mechanical impedance plate transfer matrix could be obtained. The units of the mechanical impedance, cavity and MPP were connected in series with the use of the transfer matrix method, thus creating the composite structure＇s theoretical calculation model. The qual- ity factor affecting absorption bandwidth was analyzed. Bandwidth is inversely proportional to the mechanical impedance plate mass. During the experiments, when at close to 400 Hz, the composite structure reached an absorption peak with a coefficient of above 0.8. Experimen- tal results concurred with theoretical calculations. Mechanical resonance is added based on the traditional MPP resonance sound absorption mechanism. Through this, the performance of low frequency sound absorption can be improved without increasing the thickness of the structure. The frequency band can be broadened by reducing the mechanical impedance plate mass and controlling its boundary-damping coefficient.

关 键 词：ab Enhancement of low-frequency sound absorption of microperforated panels by adding a mechanical impedance 

分 类 号：TH113.1[机械工程—机械设计及理论]