Study On The Acoustic Properties Of Porous Material-superstructure Composite Absorbers

As one of the four major pollution problems in the world,noise has a serious impact on the social environment with people's life.So improving noise pollution will promote social harmony and improve people's happiness.However,the usual sound absorption and noise reduction materials have the good absorption effect on high-frequency sound waves and are weak at low frequency.Superstructure sound-absorbing materials have a broad application prospect because of their small size and low-frequency sound absorption characteristics.In this paper,the parametric analysis of the acoustic characteristics with porous material-QRD composite and superstructure sound absorber is carried out through simulation and experimental verification.The finite element simulation method is used for the foamed aluminum-QRD composite structure,and the simulation analysis model is established by using COMSOL software and verified by experiments.Taking the composite absorbers with different back cavity structures as the research object,the effects of different structural parameters(dimension,order,depth,etc.)of QRD and the structural and acoustic parameters of porous materials(porosity,characteristic length,etc.)on the sound absorption coefficient were studied by the method of control variables.The results show that in the aspect of QRD structure,the depth and nesting mode of the cavity have great influence on the sound absorption coefficient,and the thickness and porosity of porous materials also have a certain influence on the sound absorption performance of the structure.According to the sound absorption principle of folded metamaterial materials,metamaterial absorbers with different number of cavities are designed for different low frequency ranges,and the influence of structural parameters on sound absorption coefficient is explored and verified by experimental instruments.The acoustic characteristics of 8-channel and 12-channel folded metamaterial sound absorbers are calculated and analyzed.it is found that embedding perforated plates in the structure will make the overall sound absorption coefficient curve shift to low frequency,and the crimped metamaterial is compared with it.The results show that the folded metamaterial has a wide application prospect in low frequency sound absorption.