基于机械品质因数的全波压电超声换能器设计

针对全波压电超声换能器常规设计方法存在的尺寸参数较多、计算较复杂等问题，研究了一种利用机械品质因数设计全波压电超声换能器的方法。基于压电超声理论推导了全波压电超声换能器的频率方程，利用电学理论推导了全波压电超声换能器各组成部分的等效电路，利用等效电路求取了在任意等效截面处的等效机械阻抗，进而推导出全波压电超声换能器各部分尺寸参数与其机械品质因数的关系式。利用机械品质因数及频率方程的等高线图，对全波压电超声换能器各部分尺寸进行了设计计算。利用ANSYS对该尺寸全波压电超声换能器的谐振频率进行了仿真分析，结果表明所设计的全波压电超声换能器的谐振频率具有较高的精度，满足工程应用的要求。

Design of full wave piezoelectric ultrasonic transducer based on mechanical quality factor

In the conventional design method of full wave piezoelectric ultrasonic transducer, more size parameters and complex calculation are needed. A method of designing full wave piezoelectric ultrasonic transducer based on mechanical quality factor is proposed. The frequency equation of the full wave piezoelectric ultrasonic transducer is derived based on the piezoelectric ultrasonic theory. The equivalent circuit of each component of the full wave piezoelectric ultrasonic transducer is derived by using the electrical theory. The equivalent mechanical impedance at any equivalent section is derived according to the equivalent circuit. Then the theoretical relationship between the size parameters of each part of the full wave piezoelectric ultrasonic transducer and its mechanical quality factor is derived. By the contour maps of mechanical quality factor and frequency equation, the dimensions of each part of the full wave piezoelectric ultrasonic transducer are designed and calculated, and the resonance frequencies of the full wave piezoelectric ultrasonic transducers with these dimensions are simulated and analyzed by ANSYS. Results show that the resonance frequency of the designed full wave piezoelectric ultrasonic transducer has high precision and meets the requirements for engineering application.