SOUND ABSORPTION PERFORMANCE OF A SINGLE LAYER MACROMOLECULE MICROPERFORATION BOARD BASED ON MAA COMPUTING

摘要

The porous sound-absorbing material of binary systems consisting of ethylene-propylene diene monomer (EPDM) filled with molecular sieves (MS), while EPDM was chosen as the matrix polymer and MS as filler and pore former were investigated. The acoustic behavior of the EPDM/MS composites was obtained using an impedance tube. The influence of the depth of cavity on the acoustic absorption performance of composite material is studied. Sound absorption coefficient test showed that by addition of MS, absorption coefficient was remarkably increased up to 0.45 and its peak position was low frequency, demonstrating that EPDM/MS composite is a promising sound absorption material. Mechanic performance analysis of various MS content revealed that EPDM/MS composites have the possibility of application to engineering applications as sound absorbers. In addition, the analysis shows that the acoustic performance of composite materials is 20% and the thickness is 4 mm in the low frequency range, and the peak value of acoustic absorption coefficient is 0.65 at 2500 Hz. Based on theories of Maa, a formula of absorption coefficient is proposed in this paper on taking no account of the effect of interaction between perforations. The formula is used to calculate the absorption coefficient and the resonance frequency. Experiment is done to test the model. The results show that the structure parameters of the micro-perforated panel affect its absorption coefficient, the model can be used to search for the absorption coefficient more efficiently, and the calculated result approaches the experimental.