一种新型径向复合压电陶瓷超声换能器径向振动特性研究

研制了一种新型径向复合压电陶瓷超声换能器,并对其径向振动特性进行了理论及实验研究.该换能器由一个厚度方向极化的压电陶瓷薄圆环及一个金属圆环组成.对压电陶瓷圆环和金属圆环的径向振动分别进行了分析,得到了各自机电等效电路.在此基础上,利用换能器径向力及径向振动速度的连续条件,得出了压电陶瓷径向复合超声换能器机电等效电路及其共振频率方程.分析了换能器的共振及反共振频率、有效机电耦合系数与其几何尺寸之间的关系.结果表明,在换能器压电陶瓷圆环内外半径保持一定情况下,换能器半径比增大时,共振及反共振频率随之增大.对于换能器第一阶径向振动,其有效机电耦合系数随半径比增大单调增大,而第二阶径向振动有效机电耦合系数随半径比增大单调减小.

Study on the radial vibration of a new type of radial composite piezoelectric ceramic ultrasonic transducers

A new type of radial composite piezoelectric ultrasonic transducers is presented and its radial vibration is studied.The radial vibration of a piezoelectric ceramic thin ring and a metal thin circular ring are analyzed and their electro-mechanical equivalent circuits are obtained.Using the radial boundary conditions,the electro-mechanical equivalent circuit of the radial composite ultrasonic transducer is derived and the resonance frequency equation is obtained.The relationship between the resonance frequency,the antiresonance frequency,the effective electro-mechanical coupling coefficient and the radius ratio is analyzed.It is illustrated that when the radius ratio is increased,the resonance and anti-resonance frequency are increased;the effective electro-mechanical coupling coefficient for the first radial vibration is increased;while the effective electro-mechanical coupling coefficient for the second radial vibration is decreased.