自作した電磁超音波探触子による欠陥の画像化
Visualization of Defects by Self-produced Electro-Magnetic Acoustic Transducer
著者:
大下 敬之 Takayuki OHSHITA 松本 英治 Eiji MATSUMOTO 琵琶 志朗 Shiro BIWA
発刊日:
公開日:
Electromagnetic Acoustic TransducerNondestructive EvaluationUltrasonic ImagingUltrasonic Testing
概要
The Electro-Magnetic Acoustic Transducer (EMAT) consisting of magnets and coil can transmit and receive ultrasonic waves without contact to the specimen. So, it is expected to be used for remote testin g/monitoring of structures in severe condition. This paper discusses techniques of ultrasonic flaw detecting suitable for EMAT, e.g., waveform processing of the received signal and ultrasonic imaging t echnique. We next evaluate the characteristics of a self-produced Lorenz type EMAT such as the amplitude distribution, the directivity and the lift-off dependence of the transmitted wave. Scanning the EMAT over the surfaces of specimens with several kinds of defects and employing the above techniques, we obtain ultrasonic images which can identify the position, the size and the shape of each defect.
