LAUSR

The acoustic performance of multilayered structures (MLSs) can be identified by experiments and calculation models that use commercially available software. This paper presents both an experimental method and data processing techniques that can be used for obtaining the acoustic characteristics of MLSs. During the described experiments, three types of MLSs with different structures are designed and manufactured, and their acoustic characteristics are investigated. In addition, the porosity, flow resistivity, tortuosity, and characteristic lengths of materials are determined experimentally and by using the calculation model. A calculation model for the acoustic performance of an MLS is proposed, and the calculated absorption coefficient and insertion loss derived are compared favorably with the results of experimental data, which validates the proposed models. The analytical methods and conclusions are useful in the design and the tuning of the MLSs.