The Sound Absorption Performance Research Of Microperforated Panel Based On The Coupling Method

Because sound absorption structure of microperforated panel (MPP) can obtain a better sound absorption performance in low frequency and won’t cause pollution to the environment, it has become a research hotspot in the21st century. It is especially suitable for high temperature, high humidity conditions. Based on Dah-You Maa’s basic theory of MPP, this thesis analyzes sound-absorbing performance of MPP structure, meanwhile incorporating into the vibration of MPP, the spring connecting three layers and six layers structures of MPP are also studied.On the basis of Dah-You Maa’s MPP theory, the acoustic impedance of the multi-layers structure of MPP are analyzed according to the acoustoelectric analogy method. Their sound absorption coefficient are calculated by using the matlab programming, and the structure parameters of structures on their sound absorption performance are analyzed, it is illustrated that the influence of structure parameters on the single and double structure have the similarity, the structure parameters should be chosen according to the specific problems in actual application in order to obtain high absorption coefficient in the frequency range.More important, this thesis investigates the sound absorption performance of the spring connecting three layers and six layers structure of MPP. According to the forced vibration equation for oscillator, the fluid-structure coupling boundary condition and acoustic boundary condition, their absorption coefficient formula are deduced. Their sound absorption curve are obtained by using matlab programming. Compared the sound absorption performance of the spring connecting three layers structure of MPP with the conventional.MPP, it is concluded that the spring connecting three layers structure of MPP in low frequency and intermediate frequency has the very good sound absorption performance, the influence of the structure parameters on the sound absorption performance of the spring connecting three layers structure are analyzed, including the cavity distance, plate thickness, hole diameter, perforation rate, mass per unit area of plate and the elastic coefficient of spring. The sound absorption performance of the three layers structure and the six layers structure are compared, it is showed that the sound absorption performance of the six layers structure is better than the three layers structure. Furthermore the mass per unit area of plate and the elastic coefficient of spring on the influence of the sound absorption performance of the spring connecting six layers structure are analyzed.