New Type Of Radial Composite Piezoelectric Ultrasonic Transducer

Three kinds radial composite piezoelectric ultrasonic transducer are composite disk piezoelectric ultrasonic transducer, composite pipe piezoelectric ultrasonic transducer and composite ring piezoelectric ultrasonic transducer. Main features are simple structure, stable performance, easy lineup, lagrer radiated sound area, high efficiency, Uniform and non-directional along the circumferential, therefore, it is ususlly used as small power transmitting or receiving transducer underwater in the field of underwater, ultrasonics, ocean development and geological exploration. In addition, composite pipe piezoelectric ultrasonic transducer contributes greatly to ultrasonic cleaning and large-scale liquid proscessing, so it has broad application prospects.Up to now, piezoelectric resonances are mostly thick-wall resonance polarized in the thickness direction or thin-wall resonance polarized in the radial direction. All piezoelectric resonances are driven in radial, and the axially and tangentially poled ceramic require different electrodes for poling and operating. To create axial poling in a circular cylindrical shell, a relatively high voltage is needed between the two end faces of the shell. There is almost no application in engineering. In comparison, radially polarized cylindrical ceramic shells use the same electrodes for poling and operating, and a relatively low voltage across the relatively small shell thickness is needed for poling. Therefore, radially polarized ceramic shell transducers have advantages in their manufacturing.The radial composite piezoelectric ceramic transducer is studied in radial vibration in this paper, which mainly includes the following aspects:1. The metal tube and the thin ring are reserched in radial vibration, respectively. Their radial electro-mechanical equivalent circuits and input force impedance are obtained. The resonance frequency equation is derived out. It is illustrated that the numerical radial resonance frequencies are in good agreement with the theoretical results from the resonance frequency equation. The contacts and differences between tube and ring are discussed in radial vibration.2. The thick-wall piezoelectric ceramic tube and the thin ring with radial polarization are investigated in radial vibration, respectively. Their radial equivalent circuits and equivalent impedance are derived out. Based on the equivalent circuits and using the boundary conditions, the resonance and anti-resonance frequency equations are also obtained.anti-resonance. By virtue of MAPLE, impedance curve displayed as a function of the frequency is shown, the relations between the resonance frequency, the anti-resonance frequency, the effective electromechanical coupling coefficient and the radius ratio are analyzed. Resonance and anti-resonance frequencies of different radius piezoelectric ceramics are calculated by use of numerical method, which are consistent with finite element analysis results and experimental tests. All these provide the basis for the composite pipe piezoelectric ultrasonic transducer theoretical research and design. And the contacts and differences between piezoelectric ceramic tube and ring are discussed in radial vibration.3. The radial composite piezoelectric ultrasonic transducer, composite pipe piezoelectric ultrasonic transducer and composite ring piezoelectric ultrasonic transducer, are proposed, and their radial vibration property are studied. Their radial equivalent circuits and equivalent impedance are derived out. Based on the equivalent circuits and using the boundary conditions, the resonance and anti-resonance frequency equations are also obtained.anti-resonance. By virtue of analytical and numerical methods, admittance curve displayed as a function of the frequency are shown, respectively. And they are consistent with each other. The theoretical relations between the resonance frequency, the anti-resonance frequency, the effective electromechanical coupling coefficient and the radius ratio are analyzed, the cuves are given.