Author(s)

Riichi Murayama, Makiko Kobayashi, Kuo-Ting Wu, Cheng-Kuei Jen

Fukuoka Institute of Technology, Fukuoka, Japan.
Kumamoto University, Fukuoka, Japan.
Mcgill University, Montreal, Canada.
National Research Counsil of Canada, Ottawa, Canada.

Integrated Ultrasonic Transducers (IUTs) have been developed for high-temperature nondestructive evaluation applications. In many field, it would be helpful if a pipe covered by a protective layer of about 10 cm thickness, which is under operation at several hundred Celsius, could be inspected from above the protective layer by an IUT. As a first step toward achieving the inspection of such a pipeline, an induction-based method using coils is presented together with IUTs. This study focuses on the effects of the separation distance (liftoff) between the coils on the ultrasonic signal strength and bandwidth of the IUTs. Ultrasonic signals were generated and received by the IUTs on a steel plate with a sufficient strength for thickness measurements when the liftoff was 20 cm. It was also shown that a ferrite disc together with the coils enhanced the received signal strength even when the liftoff was over 10 cm.

Ultrasonic Wave; Noncontact Sensing; Integrated Ultrasonic Transducer; Electromagnetic Induction Law

R. Murayama, M. Kobayashi, K. Wu and C. Jen, "Noncontact Driving System Using Induction-Based Method and Integrated Piezoelectric Ultrasonic Transducers," Journal of Sensor Technology, Vol. 2 No. 2, 2012, pp. 60-67. doi: 10.4236/jst.2012.22009.