多层吸声材料吸声系数的理论计算

目前由穿孔板和空腔以及多孔吸声材料组成的多层吸声材料的吸声系数还没有理论方法求解，本文提出了一种多层吸声材料吸声系数的理论解法。首先，对于由穿孔板和空腔或穿孔板和吸声材料组成的多层吸声材料，用等效声电类比图求出声阻抗，从而求得吸声系数；然后，对由穿孔板和空腔以及吸声材料组成的多层吸声材料，利用递推方法求得声阻抗，从而求得吸声系数。最后，对由不同层材料组成的多层吸声材料的吸声系数进行了理论计算，并与实验结果进行了对比，结果表明：用该方法理论计算多层吸声材料的吸声系数是可行的。

Calculation of absorption coefficient of the multiple-layer absorbers

Owing to the fact that no existing theoretical formula can be used to calculate the absorption coefficient of the multi-layer absorbers composed of perforated plates, cavities and porous absorbers, a theoretical method for this calculation is proposed in this paper. First, the acoustic impedance and the absorption coefficient of the multi-layer absorbers composed of perforated plates and cavities or perforated plates and porous absorbers are calculated by using the sound-electro analogy. Then, the acoustic impedance and the absorption coefficient of the multi-layer absorbers composed of perforated plates, cavities and porous absorbers are calculated by using stepped deductions. Theoretical calculation of the absorption coefficients of three types of multi-layer absorbers composed of different materials including perforated plates is carried out, and the results indicate that using this method to calculate the absorption coefficients of the multi-layer absorbers is feasible in contrast with the experimental results.