입사음과 반사음을 분리하는 압전 트랜스듀서 설계 및 제작 = Design and Fabrication of Piezoelectric Transducers Separating Incident and Reflected Wave

다국어 초록 (Multilingual Abstract)

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.

국문 초록 (Abstract)

본 논문은 비파괴검사 분야에서도 초음파탐상검사를 위해 많이 사용되는 압전 트랜스듀서를 설계하는 데 있어 새로운 기법을 제시한다. 입사음과 반사음 분리를 목적으로 수학적 기반해석을 바탕으로 한 트랜스듀서 설계 및 제작했다. 설계된 트랜스듀서는 음향 윈도, 2개의 수신센서, 1개의 구동센서 층으로 된 형태를 가진다. 반사와 굴절을 최소화하기 위해 물과 유사한 임피던스를 가진 Aptflex을 음향윈도로 사용하였다. 수신센서는 넓은 범위를 수신할 수 있는 PVDF(polyvinylidene fluoride)를 사용하였고, 구동센서로 압전소자(piezoelectric transducer)를 사용했다. 트랜스듀서를 설계하기 위해 KLM (Krimholtz, Leedham and Matthaei) Model 방식을 사용하여 수학적 기반해석을 구현하였다. 전달되는 음파의 1/4파장으로 2개의 수신센서 및 구동센서가 위치하도록 몰드를 제작하였고, 센서 사이에 음향 윈도를 채워 트랜스듀서를 제작하였다. 완성된 트랜스듀서의 임피던스 및 위상차와 수학 기반해석을 바탕으로 계산된 임피던스 및 위상차가 유사했고, 실험을 통해 2개의 수신센서를 통해 수신된 신호 차이가 1/4파장으로 정확하게 맞지는 않았지만 그 근처의 값을 얻을 수 있었다. 이를 통해 제작한 트랜스듀서가 설계한 대로 작동함을 확인하였다.

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