입사음과 반사음을 분리하는 압전 트랜스듀서 설계 및 제작

초록

This study presents a new technique for designing piezoelectric transducers which are widely used for ultrasonic inspection in the non-destructive inspection field. A piezoelectric transducer was designed and fabricated using mathematical basis analysis for separating incident and reflected sound in water. The transducer unit consisted of acoustic windows, two receiving sensors, and one transmitting sensor as layers. To minimize and reflections, Aptflex was used as the acoustic window, which has impedance similar to that of water. The receiving sensor used polyvinylidene fluoride to receive a wide range, and a piezoelectric transducer was used as a transmitting sensor. To design the transducer, we applied mathematical basis analysis using the Krimholm, Leedham and Matthaei method. A mold was fabricated so that two receiving sensors and a transmitting sensor were positioned at a quarter wavelength of the transmitted sound wave, and a transducer was manufactured by filling an acoustic window between the sensors. The measured impedance and phase values were similar to the calculated impedance and phase values derived from mathematical-basis analysis. Experiments revealed that the difference between the two signals received by the two receiving sensors was not exactly equal to one quarter of the wavelength, but a near value of one quarter of the wavelength was obtained.

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