Piezoelectric circular ring flexural transducers.

An analytical treatment of the piezoelectric ceramic complete ring transducer undergoing flexural vibrations is presented. Conditions for the electromechanical excitation of the flexural vibrations are discussed and it is shown that the fundamental mode of the flexural vibration of a complete ring can be considered as sufficiently dominant over a broad frequency range. Hence, the one-dimensional equivalent electromechanical circuit representation of the transducer is applicable and all the parameters of the equivalent circuit are determined. Possibilities to optimize the effective coupling coefficient of the transducer by changing the extent of the electrodes on the piezoelectric body are considered. It is shown that for effective operation of the flexural ring transducer as a low frequency hydroacoustic projector the opposing quadrants (or three quadrants in case of a planar array configuration) have to be covered with baffles. The radiation impedance and directional factors of the transducers with baffles are considered. Limitations of the acoustical power radiated by the transducers are discussed.