Vibroacoustic response of a cylindrical shell with a multilayered locally resonant coating

Abstract

A multilayered viscoelastic material used as an external coating on a marine vessel for underwater noise control is presented. The multilayered coating is designed using regular distributions of vacuous cavities and hard steel scatterers that yield monopole and dipole scattering responses, respectively. The coating is modelled as an equivalent fluid in which the layers of inclusions are modelled as homogenized layers with some effective properties. The coating is externally applied to a submerged cylindrical shell. Fully coupled fluid–structure interaction between the coated shell and the surrounding water is taken into account. The material and geometric parameters of the inclusions are observed to have a significance influence on the radiated sound from the shell. Different combinations of the material distribution of the inclusions on the vibroacoustic response of the submerged shell are presented, showing that the local resonances of the inclusions can be tuned to reduce the radiated sound in a broad frequency range.