Flexible 위상배열초음파 탐촉자를 이용한 불균일 표면 시편의 Total Focusing Method 영상화 연구 = Study on Total Focusing Method Imaging of Irregular Surface Specimen Using Flexible Phased Array Ultrasonic Probe

국문 초록 (Abstract)

접촉식 탐촉자를 사용하는 일반적인 초음파검사에서 검사체에 굴곡이 있거나 불균일한 표면 형상을 가지고 있는 경우 탐촉자와 검사체 사이에 틈새가 발생한다. 탐촉자와 검사체 사이의 틈새에 의한 불균일한 접촉 상태로 인해 초음파 빔이 왜곡되고 감도가 감소되며 결함검출 능력이 저하되는 문제점이 발생하게 된다. 이번 연구에서는 이러한 문제를 해결하기 위해 2차원 flexible 위상배열초음파 탐촉자를 이용하여 표면 형상이 반영된 Total Focusing Method(TFM) 이미지를 합성하는 기법을 개발하였다. 탐촉자 내부에 장착된 변위 센서를 이용하여 표면 형상을 측정하였고, Half Matrix Capture(HMC) 기법으로 수집된 데이터와 측정된 표면 형상 데이터의 후처리를 통해 표면 형상 반영 TFM 이미지를 합성하였다. 일반 위상배열초음파 검사와 비교하였을 때 표면 형상 반영 TFM 기법이 굴곡을 가진 표면에서 결과 이미지의 감도와 선명도가 향상되는 것을 확인할 수 있었다.

다국어 초록 (Multilingual Abstract)

In the conventional ultrasonic inspection probes of components with curved or irregular surfaces using contact probes, there is often produces a gap between the probe and the components. The uneven coupling due to the gap leads to ultrasonic beam distortions and losses of sensitivity, which can degrade the inspection performance. Accordingly, in this study, we developed a method to reconstruct Total Focusing Method (TFM) images corrected by a surface profile using a two-dimensional flexible ultrasonic phased-array probe in order to overcome these problems. We obtained the surface profile using displacement sensors embedded in the transducer and reconstructed the surface-adaptive TFM image through the post-processing data acquired using the Half Matrix Capture (HMC) and the measured surface profile data.
The surface-adaptive TFM method showed an improvement in the sensitivity and sharpness of the resulting image on a curved surface compared with conventional ultrasonic phased array testing.

참고문헌 (Reference)

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