阻尼耦合双层微穿孔板吸声体研究

提出并研究一种利用两板间微缝进行阻尼耦合的双层微穿孔板(DMPP)吸声体。该吸声体在两层微穿孔板(MPP)之间形成一个宽度小于1mm的微缝,因此其阻尼不仅可由板上的微穿孔提供,还可由两板之间形成的微缝提供。采用声电类比法建立了DMPP转移阻抗的理论模型,并进行实验验证,结果表明理论计算结果与实验吻合较好。然后利用建立的理论模型,对单层MPP和DMPP吸声体的吸声性能进行了对比研究,结果表明,相比于单层MPP,DMPP可以利用微缝提供的阻尼显著改善吸声性能,同时减少实际板厚。最后,对DMPP吸声体的吸声性能及其几何参数的关系进行研究,结果表明,当保持其它结构参数不变时,微缝宽度对DMPP吸声系数的提高存在一个最优值,超过或低于此值会导致吸声系数下降。

Research on damping coupled double-layer microperforated panel sound absorber

A double-layer microperforated plate (DMPP) absorber that uses a microslit between two plates for damping coupling is proposed and investigated. The absorber forms a microslit of less than 1 mm thickness between the two layers of MPP, so its damping can be provided not only by the microperforations on the plate, but also by the microslit formed between the two plates. The theoretical model of the transfer impedance of DMPP was established by the acousto-electric analogy method and experimentally verified, and the results showed that the theoretical calculation results were in good agreement with the experiment. Then, using the established theoretical model, a comparative study of the sound absorption performance of single-layer MPP and DMPP sound absorbers was conducted, and the results showed that compared with single-layer MPP, DMPP can significantly improve its sound absorption performance by using the damping provided by microslits while reducing its actual plate thickness. Finally, the relationship between the sound absorption performance of the DMPP absorber and its geometrical parameters is investigated, and the results show that there is an optimal value for the improvement of the sound absorption coefficient of DMPP by the microslit thickness when other structural parameters are kept constant, above or below which the sound absorption coefficient decreases.