Study on Acoustic Transmission Loss of Materials with Transfer Matrix-Impedance Tube Methods

The acoustic transmission loss of materials is studied from the sound field changes of material internal and external parts.At first the sound transmission characteristics of laminated composite materials are analyzed by transfer matrix method.The formula of sound pressure transmission coefficient acoustic transmission loss with the density,sound velocity,thickness and frequency changes are derived in normal incidence plane wave.Then the 4-channel impedance tube with single-sensor for testing transmission loss(TL) of acoustic materials is introduced,and the math-formulas for calculating is also derived.At last,the theory simulation calculation and experimental test are conducted with certain thickness plate and laminated composite materials.The results show that the experimental results accord well with the theoretical ones.