The Structural Design of Combined Absorber Composed by MPP and Multi-Layer Porous Material Based on VA One

Some experiments found that the low-frequncy sound absorption performance can be improved by inserting MPP into the multi-layer porous materials, but the theory modeling of this MPP-multi-layer porous combined absorber is too difficult to provide the guidance. Therefore, a new method is proposed in this paper, according to Atalla’s theory, the MPP can be treated as a rigid porous layer in this composite absorber, then the acoustic software (such as VA One) usually for dealing with multi-layer porous absorber can be chosen to its optimal design. Based on this method, a two-layer porous absorber is designed using the Foam Module of VA One, and the influence of different insert location of MPP in the two-layer porous absorber is analyzed, which shows the existence of optimum location. Moreover, the sound absorption of different MPP structure at the optimum location is also discussed which shows inserting the wider-band MPP structure is better.