Research on Sound Insulation Characteristics and Application of Acoustic Metamaterials 2022-01-0343

In the field of low-frequency noise control, the acoustic metamaterials have received extensive attention from researchers. However, the existing work mainly focuses on small structures with fixed boundaries, which is quite different from engineering applications. Based on the membrane-type acoustic metamaterials, this paper uses a rigid thin plate to replace the tensioned membrane, design and manufacture of two new types of local resonance structure and studies their sound insulation properties. First, the metamaterial samples with a small size of 100mm in diameter and a large-size square with a side length of 506mm were produced, and the sound TL of the two was tested through the impedance tube and the reverberation chamber-anechoic chamber, respectively. The results show that the new structure can form an obvious sound insulation frequency band at low frequencies. Based on the finite element method, a metamaterial acoustic transmission loss calculation model is established. Comparing and analyzing the calculated value of sound transmission loss with the test value, the validity of the calculation model is verified. Based on the calculation model, the influence of the boundary conditions and cell parameters of the metamaterial on the sound insulation properties of the metamaterial is analyzed. In order to explore the application feasibility of acoustic metamaterials in automobiles, some square samples with a side length of 506mm were produced, which are acoustic metamaterials combined with traditional acoustic materials (such as sheet metal, thermoplastic fibers) combined in different ways. Then, the sound transmission loss of these samples was tested through the reverberation chamber-anechoic chamber. The results show that the advantages of low-frequency sound insulation can be well expressed when the double-wall structure is formed.