Jiang W., Liu X., Wang C.

The micro-perforated panel absorbers with heterogeneous cavities are widely used in acoustic engineering because of its advantage in widen frequency band. However, it is not easy to predict the impedance by theoretic or numeric method. A numeric method is presented to predict the normal incidence acoustic absorption coefficient for the micro-perforated panel absorbers with heterogeneous cavities, which can be consider as the combination of MAA Dah-you¡¯s theory about micro-perforated panel absorbers and the numeric simulation with boundary element method. The acoustic absorption coefficients of three absorbers with triangular prism back cavity and one absorber with cone back cavity are simulated and measured by stationary wave tube. It can be found that the numeric predictions are quite agreement with the experimental results. Then, this method is used forecast the absorption coefficient spectrum in designing a new noise barrier with heterogeneous cavity, and dimension of back cavity and other parameters can be easily optimized according to the absorption coefficient simulation. The predicted absorption coefficient spectrum of this noise barrier agrees with measured the results in reverberation chamber. All of these show that the presented method is can be applied to predict the absorption performance of the micro-perforated panel absorbers with heterogeneous cavities instead of experiment, which will make the design of this kind of absorbers more efficient than before.