An investigation on acoustic performance for viscoelastic coating containing axisymmetric cavities using multiple scattering method

A semi-analytical/numerical model based on multiple scattering (MS) method has been established for analyzing the effect of acoustic performance on main energy attenuation mechanism in viscoelastic coating containing axisymmetric cavity. The basis functions of stress and displacement of axisymmetric cavity surface are derived in the system of spherical coordinates. The transition matrix between the incident wave and scattering wave are obtained by the numerical integral of the basis functions of cavity surface. The reflection, transmission and absorption performance of viscoelastic materials containing periodic cavities are calculated using MS method and wave propagating theory of multi-layered medium. The results indicate that low frequency energy is mainly attenuated through cavity resonance. The resonant properties are found to be very sensitive to the boundary conditions. The coupling of the double-cavity is capable of extending the absorption to even lower frequencies. The absorption performance of viscoelastic coating in the high frequency range is independent of the backing material. Its energy attenuation depends mainly on acoustic properties of cavity scattering and mode conversion.