Introduction of various energy transfer mechanisms of underwater acoustic transducers

From the perspective of energy conversion, transducers can be mainly divided into piezoelectric ultrasonic transducers that use the piezoelectric effect to achieve energy conversion and utilize magnetostriction.

The effect of a magnetostrictive transducer that achieves energy conversion, the ultrasonic depth transducer referred to in the foregoing are all one of these two types, and they are common.The feature is based on functional materials to achieve energy conversion. Fiber optic hydrophone based on photoelastic effect pick-up. In addition, several other types of transducers are used in the field of underwater sound. Here are briefly introduction as follows:

(1) Electric transducers, which use magnetic fields and currents to interact, similar to ordinary speakers and transducer. The radiating surface of the device is mechanically connected to a coil placed in a static magnetic field. When the coil flows through the current of the working signal frequency, the coil is finally converted into an alternating oscillation of the radiating surface by the magnetic field force to radiate the acoustic energy of the working signal frequency. This type of underwater acoustic transducers have low operating frequency, large dynamic amplitude, frequency bandwidth, etc.

Mechanically driven hydroacoustic transducer by using mechanical motor to drive transducer piston radiation through some mechanical structure such as crankshaft-link
The surface is reciprocating, the operating frequency can be adjusted by changing the rotational speed of the motor, and the maximum driving reciprocation of the driving point of the crankshaft is changed.About the stroke, that is, adjusting the vibration displacement amplitude of the radiating surface of the transducer. This type of transducer has no resonance characteristics and is generally not suitable for generating complex acoustic signals.

Hydrodynamic hydroacoustic transducer that uses a pump system or mechanical structure to drive fluid to oscillate through a working radiating surface directly.Radiating sound waves into the waters connected to it. This type of underwater depth sounder transducer can radiate louder sound energy and is not suitable for generating complex sounds.Signal, generally only used to assist the experimental sound source.Resonant underwater acoustic transducer is designed with a certain lumen size tubular structure, stimulates the fluid oscillation in the cavity through mechanical structure or other forms of transducer, and can excite a strong line spectrum acoustic signal at the resonant frequency of the cavity.This type capacitive piezoelectric transducer has a narrow frequency band and can be used as a low frequency sound source.