径向复合圆柱压电超声换能器

提出一种三元径向复合圆柱压电超声换能器,并对其径向振动特性进行了研究。基于弹性力学理论及机电类比原理,导出了柱坐标系中分割处理径向极化压电陶瓷管准厚度模振动及薄壁短圆管径向振动的机电等效电路;利用径向力和振速连续的边界条件,得出了径向复合圆柱压电换能器系统的径向振动机电等效电路及其共振频率方程。探讨了换能器径向共振频率及有效机电耦合系数随其几何尺寸的变化关系。研究表明,换能器的径向共振频率及有效机电耦合系数随其内芯半径和预应力管壁厚度增大而降低。研制了一些径向复合圆柱压电换能器,并对其径向共振频率进行了测试。结果表明,理论与实验结果基本一致。 

The radial composite cylindrical piezoelectric ultrasonic transducer

The radial vibration of a new kind of ternary radial composite cylindrical piezoelectric transducer is studied. Based on the elastic mechanics theory and the electromechanical analogy,the electromechanical equivalent circuits of the segmented radially polarized piezoelectric ceramic tube in quasi-thickness vibration and a thin-walled metal pipe in radial vibration are obtained.By considering the continuous boundary conditions of the radial force and vibration velocity on the each interface of the transducer,the radial vibration equivalent circuit of the radial composite cylindrical 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 radial resonance frequency and the effective electro-mechanical coupling coefficient of the transducer are decreased with the radius of the inner core and the wall thickness of the prestress pipe of it increased.Finally,the radial resonance frequencies of some radial composite cylindrical piezoelectric transducers are tested.It is shown that the theoretical radial resonance frequencies are in a good agreement with the measured results.