中文摘要：

对一种镶拼式复合压电超声换能器的径向振动特性进行分析。该镶拼式复合压电超声换能器由弹性内芯、矩形压电陶瓷晶堆环组及金属预应力管径向复合而成。采用压电陶瓷晶堆,可大幅提高换能器的功率容量及有效机电耦合系数。依据机电类比原理,得出换能器的机电等效电路和共振频率方程;探讨换能器的第1、2阶共振和反共振频率及机电耦合系数与其几何尺寸之间的关系,并进行有限元仿真分析和试验测试。研究表明,换能器第1阶径向共振及反共振频率随其内芯内径及预应力管外径增大而降低;第2阶共振频率随内芯内径增大存在极小值,但随预应力管外径增大而下降,并且第2阶共振模式的有效机电耦合系数较高。对换能器共振频率的测试和仿真表明,理论与试验及仿真结果相符合。

英文摘要：

The regular polygon composite piezoelectric ultrasonic transducer is studied. The transducer consists of a metal inner core, a regular polygon of rectangular piezoelectric ceramic piles and a prestress metal tube. Using the piezoelectric ceramic piles, the effective electro-mechanical coupling coefficient and the power capacity of the transducer are greatly improved. Based on the electro-mechanical analogy theory, the equivalent circuit and the resonance frequency equation of the transducer in radial vibration are derived. The relationships between the first and second order resonance and anti-resonance frequency, the effective electro-mechanical coupling coefficient and the geometrical dimensions of the transducer are analyzed by theoretical and finite element numerical simulation analysis and experimental testing. It is shown that the first radial resonance frequency is decreased monotonically with the inner diameter of the inner core and the outer diameter of the outer prestress tube of the transducer increased. The second radial resonance frequency of the transducer gets extremum value with the increase of the inner diameter of the inner core, while decreased monotonically with the increase of the outer diameter of the outer prestress tube. In addition, the effective electro-mechanical coupling coefficient of the second order radial vibration mode is higher than that of the first order. It is also shown that the results of the theoretical analysis and the finite element analysis are in a good agreement with that of the measurements.