夹心式压电超声复频换能器的研究

Study on the Multifrequency Sandwiched Piezoelectric Ultrasonic Transducer

对具有多个共振频率的纵向振动夹心式压电超声换能器进行了研究，该换能器由多组压电陶瓷片及金属棒组成。在一维纵向振动理论及等效电路的基础上，推出了夹心式复频超声换能器的共振频率方程，设计并制作了一些复频换能器，并对换能器的共振频率、有效机电耦合系数和等效电阻抗等参数进行了测试。试验表明，换能器的实测频率与设计频率基本一致，在实际工作状态下，此类换能器可在不同的共振频率下工作。对于具有两个共振频率的换能器，其振动模式分别为半波及全波振动模式。

Multifrequency sandwiched piezoelectric transducer consists of metal cylinder and piezoelectric ceramic pile. Based on the one dimension longitudinal vibration theory,the resonance frequency equation of the multifrequency transducer is derived out.Some transducers of this kind are designed and made,and the resonance frequencies,the equivalent electric impedance and the ef-fective electromechanical coupling coefficient are measured.Experiments show that the measured resonance frequencies of the transducers are in good agreement with calculated values. The trans-ducers can resonate at different frequencies with half wave and full wave vibrational modes.