Underwater sound radiation from an elastically coated infinite plate with periodic inhomogeneities of finite width

The underwater sound radiation from a line-force-driven coated infinite plate with periodically attached distributed inhomogeneities is investigated. A typical example of a distributed inhomogeneity is a signal conditioning plate (SCP), which can be inserted between the coating and a hydrophone to increase the strength of the incoming signal. Using the wavenumber transform approach, the surface normal velocity and radiated sound power of the plate are determined by solving the indexed equations of the wavenumber components. This study demonstrates that the elastic coating between the base plate and periodic inhomogeneities may reduce the effect of band-passes and band-gaps on the radiated sound power caused by the inhomogeneities. This is explained in detail by the insulation effect of the coating as a decoupler. The effect of the SCP's width and spatial period on the radiated sound is also examined. Finally, recommendations are given for the application of SCPs for underwater sensing purposes. (C) 2017 Acoustical Society of America.