压电陶瓷圆环与金属圆环复合振动系统的径向振动

对由压电陶瓷圆环与金属圆环组成的复合振动系统的径向振动特性进行了研究。首先分析了压电陶瓷圆环和金属圆环的径向振动，推出了其各自的机电等效电路。在此基础上，得出了压电陶瓷圆环与金属圆环复合振动系统的机电等效电路及其共振频率方程。探讨了系统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。研究表明，当复合振动系统的壁厚比增大时，其共振及反共振频率升高。对于换能器的第一阶径向振动，其有效机电耦合系数随壁厚比的增大而单调减小；对于换能器的第二阶径向振动，其有效机电耦合系数随壁厚比的增大会出现一个极大值，而且，在一定的壁厚比范围内，换能器第二阶径向振动的有效机电耦合系数大于第一阶径向振动的有效机电耦合系数，这一规律与传统的有关压电换能器的分析理论及结果是有所不同的。

Radial vibration of a composite ultrasonic system of piezoelectric and metal rings

The radial vibration of a composite ultrasonic vibration system is studied. The system is composed of a piezoelectric ceramic thin ring that is polarized in its thickness direction and a metal thin circular ring. The radial vibrations of a piezoelectric ceramic thin ring and a metal thin circular ring are analyzed respectively, and the corresponding radial electro-mechanical equivalent circuits are obtained. Based on the equivalent circuits and using the boundary conditions, the electro-mechanical equivalent circuit of the radial composite ultrasonic system is derived and the resonance frequency equation is obtained. The relations between the resonance frequency, the anti-resonance frequency, the effective electromechanical coupling coefficient and the radius ratio are analyzed. It is illustrated that with the radius ratio increasing the resonance and anti-resonance frequency increase and the effective electro-mechanical coupling coefficient for the fwst radial vibration decreases. Experiments show that the measured resonance frequency and anti-resonance frequency are in a good agreement with the theoretical results.