中文摘要：

对管形径向复合压电超声换能器的径向振动特性进行研究。该换能器由金属预应力管、弹性胀套内芯及柱面压电陶瓷环组径向复合而成。基于弹性力学理论及机电类比原理,推导出复合换能器的径向振动机电等效电路及其共振频率方程。探讨换能器径向共振频率、反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,换能器的一阶径向共振频率随其内芯内径及预应力管壁厚度增大而降低,有效机电耦合系数随内芯内径增大而减小,而随其外部预应力管壁厚度增加存在极大值。理论与试验结果符合较好。

英文摘要：

A new kind of tubular radial composite piezoelectric ultrasonic transducer is presented and studied. The transducer is consisted of an outer metal prestress tube, a metal expandable inner core and a ring group of cylindrical piezoelectric ceramic slice, which are composited in the radial direction. Based on the elastic mechanics theory and the electromechanical analogy, the electromechanical equivalent circuit of a ring group of cylindrical piezoelectric ceramic in quasi-thickness vibration is obtained. The radial vibration equivalent circuit and the resonance frequency equation of the tubular radial composite piezoelectric transducer arc derived. The relationship between the resonance and anti-resonance frequency, the effective electro-mechanical coupling coefficient and the geometrical dimensions of the transducer is analyzed. It is illustrated that the first order radial resonance frequency of the transducer are decreased with the inner diameter of the inner core and the wall thickness of the outer prestress tube of it is increased. The effective electro-mechanical coupling coefficient of the transducer decreased with the inner diameter of the inner core increased, while it exist a maximum value as the wall-thickness of the outer prestress tube increases. The radial resonance frequencies of some tubular radial composite piezoelectric transducers are tested. It is shown that the theoretical results are in a good agreement with that of the measurement.