Parameter Design And Experimental Verification Of Micro-perforated Panel Absorbers

Sound absorption characteristics of sound-absorbing material have notraceability transfer system international or domestic. The test of sound absorptioncharacteristic has no comparability and traceability. In this paper, the structure andparameters of typical sound absorption blocks was designed with broadband and highdamping capacity. Based on the theory of MPA (micro-perforated sound-absorbing),which was proposed by Academician Ma Dayou, the structure of sound absorptioncharacteristics are analyzed by using genetic algorithm (GA). Moreover, someparameters including perforation diameter, sheet thickness, ratio of perforationparameters, and their relationship are determined. A broadband and metal aluminumsound absorption structure is made that stable in structure, easy to save, not easyageing. The thesis mainly explores the four aspects of content.Firstly, the MPA model is summarized. And the acoustic-electric analogymethod is used for single MPA. As for the double MPA, if the cavity is less than aquarter of the wave length, acoustic-electric analogy method can be adopted. But ifthe cavity is too deep, transfer matrix method should be chosen by considering thesound quality.Secondly, the different encodings of genetic algorithm are explored. The affecton the structure of solving the optimal solution by genetic operator is recognized.Selecting the optimal encoding, and finding out the optimum parameters of MPA forthe different sound absorption frequency of100Hz-1000Hz,800Hz-5000Hz and100-5000Hz are done. The thesis mainly analyses the difference between binary codeand gray code.Thirdly, the ANSYS is used to establish impedance tube model, which isimported into LMS to conduct acoustic analysis. The all solved parameters of threekinds of MPA which have absorption frequency of100Hz-1000Hz,800Hz-5000Hzand100-5000Hz, are simulated respectively. Then the simulate curves are comparedwith the model curves obtained by using genetic algorithm. Their center frequencyand curve trend are consistent with each other.Lastly, according to the selected parameters, the aluminum is used to product theMPA structure for designing experimental scheme.The genetic algorithm is used in multilayer structure design and parameterselection of MPA in the thesis. A sound-absorbing structure with stability, wide-bandand high absorption should be designed. And the research on the traceability ofacoustical absorption coefficient in sound-absorbing material should be supported.