TITLE

EVALUATION FOR DEFECT DETECTION OVER BENDING ZONE IN PIPING BY GUIDED WAVE

AUTHOR(S)

Miki, Masahiro; Nagashima, Yoshiaki; Endou, Masao; Kodaira, Kojiro; Koike, Masahiro; Odakura, Mitsuru

PUB. DATE

February 2010

SOURCE

AIP Conference Proceedings;2/22/2010, Vol. 1211 Issue 1, p111

SOURCE TYPE

Academic Journal

DOC. TYPE

Article

ABSTRACT

Guided wave inspection technique is effective as detecting defects like corrosion in piping. Effectiveness to the straight parts in piping by the guided wave inspection has been clarified by many researches. The inspection performance using guided wave decreases due to the unwanted wave when there is a bend part in the inspection area. On above motivation, the inspection performance could be improved if the guided wave was transmitted from many circumferentially-set sensors based on the same principle as for phased-array methods. Then, the validity of phased array methods using the guided wave technique was confirmed by the following experiments using a piping with bend. The delayed pulse by phased-array methods was set from the reflected wave which was transmitted from a local defect, and it was calculated based on time reversal theory. This transmission wave was confirmed by one experiment using the guided wave focused over the bend zone. Thus, the unwanted wave caused in the bend zone could be suppressed. In addition, the reception signal processing that considered the high-order modes was examined in the second experiment on reflected wave evaluation. By combining this transmission control with the reception signal processing, it was judged that the detection performance for local defects over the bend zone could be improved.

ACCESSION #

48429566

Tags: PIPING;  SIGNAL processing;  NUCLEAR physics;  METHODOLOGY;  INFORMATION measurement

 

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