2층 압전 환판 초음파 트랜스듀서의 진동 특성

초록

This paper deals with the vibration characteristics of an ultrasonic transducer composed of two piezoelectric rings. This study is necessary to design ultrasonic sensors and actuators made of a piezoelectric ring stack. Theoretically, we obtained natural frequencies and mode shapes of radial and axial modes of the transducer from equations of motion and boundary conditions. By the finite element analysis, we obtained the impedance curves to yield natural frequencies, and the vibration amplitudes to supplement three-dimensional mode shapes. Experimentally, we measured the natural frequencies by an impedance analyzer, and we obtained radial in-plane mode shapes from the vibration amplitudes measured by a laser in-plane vibrometer. The theoretical analysis was verified by comparing three kinds of results, and we identified variations of the vibration characteristics according to the thickness of the piezoelectric rings. It was found that axial modes of the ultrasonic transducer were affected by the thickness of the piezoelectric ring whereas the radial modes were not.

키워드