Development of high temporal resolution subharmonic phased array and application to online testing of steel pipes

2014 Fiscal Year Final Research Report

• Project/Area Number: 24246119
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Material processing/treatments
• Research Institution: Tohoku University
• Principal Investigator: YAMANAKA Kazushi 東北大学, 工学(系)研究科(研究院), 教授 (00292227)
• Co-Investigator(Kenkyū-buntansha): TSUJI Toshihiro 東北大学, 大学院工学研究科, 助教 (70374965) ; OHARA Yoshikazu 東北大学, 大学院工学研究科, 助教 (90520875)
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: 分調波 / フェーズドアレイ / 閉口き裂 / 応用腐食割れ

Outline of Final Research Achievements

Since closed cracks are transparent to ultrasound, measurement error in ultrasonic testing is a difficult problem. Since welded steel pipes are widely used in structural components of important facilities, effects of accidents caused by overlook of closed cracks is serious.
Therefore, we realized measurement of closed cracks by the subharmonic phased array for crack evaluation (SPACE) in a wide area. By correcting the aberration caused by refraction at water/ steel interface, it enabled large amplitude incident waves to the cracks. Also, we developed surface acoustic wave (SAW) SPACE and fundamental amplitude difference (FAD) method to enhance the temporal resolution, and verified them with standard closed cracks. Then, we implemented those methods in the online testing equipment and verified their performance in real testing condition for production line of pipes.

Free Research Field

超音波