LAUSR

Abstract The sound absorption and sound insulation properties of multilayer composites can be changed rapidly by optimizing the combination of acoustic parameters between different layers. In order to study the influence of volume modulus, loss factors, viscosity characteristic lengths, tortuosity and other parameters on the acoustic properties of multilayer composites, the multilayer structure composed of glass wool materials, glue layers and polyurethane foams were experimentally analyzed and numerically simulated. The propagation matrix equation of sound waves in multilayer media was derived, and the influence of the above parameters on the acoustic performance of multilayer structures is studied by means of experimental analysis and inversion of the transfer matrix. The results show that the sound absorption coefficient decreases with the increase of the volume modulus of the outer material with the frequency of 2000–4000 Hz. The absorption coefficient of frequency >4000 Hz increases with the volume modulus of outer material, and the maximum absorption coefficient is 0.52. When the damping loss factor of rubber layer is 0.8, the maximum sound insulation is 40 dB. The influence of the viscosity characteristic lengths and tortuosity of the outer material on the acoustic properties is more obvious than that of the inner material.