Relationship between Lamb Waves on Fluid-Loaded Plate and Underwater Acoustic Radiation in Region below than Coincidence Frequency

The far field directional response radiated from a fluid-loaded plate vibrating with the zero-order Lamb modes is described in a region below than the coincidence frequency. The vibrated plate used is a brass plate. The transmitter used to vibrate the plate and the hydrophone used to receive the radiating wave are made of piezoelectric rubber. The directional responses of the radiating sound are obtained over a frequency range between 55 kHz and 330 kHz for a brass plate with a 1.5 mm thickness.