径向复合压电陶瓷超声换能器的径向振动特性研究

Study on the radial vibration of radial composite piezoelectric ultrasonic transducers

对径向复合压电陶瓷超声换能器的径向振动特性进行了分析。该换能器由一个厚度极化的压电陶瓷实心圆盘和一个金属圆环在半径方向复合而成。论文首先研究了压电陶瓷圆盘及金属圆环的径向振动,推出了其径向振动的机电等效电路。在此基础上,利用换能器的径向边界条件,得出了径向复合压电陶瓷换能器的机电等效电路及其共振频率方程。探讨了换能器的共振频率和有效机电耦合系数与其几何尺寸之间的依赖关系。设计并实际制作了一些径向复合超声换能器,对其径向共振及反共振频率进行了测试,并利用有限元法进行了数值模拟。研究表明,利用文中理论得出的换能器的共振频率与实测值及数值模拟结果基本符合。

The radial vibration of new radial composite piezoelectric transducers is studied. The radial composite ultrasonic transducer consists of a solid piezoelectric ceramic thin disk and a metal thin ring in radial vibration. The radial vibrations of a piezoelectric thin disk and a metal thin ring are analyzed and their radial electro-mechanical equivalent circuits are obtained. Based on the electro-mechanical equivalent circuits and the boundary conditions between the piezoelectric ceramic thin disk and the metal thin ring, the electro-mechanical equivalent circuit of the radial composite piezoelectric transducer is derived and the resonance frequency equation is obtained. The relationship between the resonance frequency, the effective electro-mechanical coupling coefficient and the geometrical dimensions is analyzed. It is illustrated that the theoretical radial resonance frequencies are in a good agreement with the measured results, and they are also in a good agreement with the results from the numerical method.