超音波可視化技術および数値解析を用いた焦点型電磁超音波探触子の評価
Evaluation of Point Focusing EMAT using ultrasonic wave visualization system and finite element analysis
著者:
手塚 晃世 （東北大） 山本 敏弘 （発電技検) 孫 宏君 浦山 良一 内一 哲哉 高木 敏行 （東北大）
発刊日:
公開日:
Ultrasonic wave visualization systemDecommissioningFinite element analysisNon-destructive testing (NDT)Pipe wall degradationPoint Focusing EMATUltrasonic testing (UT)
概要
Electromagnetic acoustic transducer (EMAT) is suited to monitoring because of its non-contacting nature. However, a standard EMAT tends to give overestimating results because the estimated thickness is associated with the average of varying thickness over an area under the coil of EMAT. To solve this problem, Point-Focusing EMAT (PF EMAT), which concentrates ultrasonic waves at a certain point, was applied to thickness gauging. This study evaluates the focusing property of PF EMAT and its applicability to local pipe wall thinning evaluation. The ultrasonic waves focused on the back wall with PF EMAT were visualized in experiments. Then, the experimental results were compared with the corresponding simulation results obtained by 2D finite element method (FEM). Finally, the focusing effect with different specimen thickness was evaluated by 2D FEM.
