Affiliations: [a] Shaanxi Engineering Research Centre for NDT and Structural Integrity Evaluation, State Key Laboratory for Strength and Vibration of Mechanical Structures, Xi'an Jiaotong University, Xi'an, Shaanxi, China | [b] Institue of Plasma Physics, Chinese Academy of Sciences (ASIPP), Hefei, Anhui, China
Correspondence:
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Corresponding author: Zhenmao Chen, Shanxi Engineering Research Centre for NDT and Structural Integrity Evaluation, State Key Laboratory for Strength and Vibration of Mechanical Structures, Xi'an Jiaotong University, Xi'an, Shaanxi, China. Tel./Fax: +86 29 8266 8736; E-mail:chenzm@mail.xjtu.edu.cn
Abstract: In this paper, an electromagnetic acoustic transducer
(EMAT) method using rotating bias magnetic field was proposed for NDT of
delamination defect in a thin multilayer tube of W-Cu monoblock in ITER
divertor. To investigate its feasibility, a numerical simulation code was
developed for EMAT signal simulation of tube configuration and uniform bias
magnetic field. The EMAT signals of a typical EMAT transducer under bias
magnetic field applied outside the tube were simulated for deboning defect
of different size in the W-Cu interface of the mono-block. The reasonable
sound speed and simple dependence of the signal amplitude on defect size
demonstrated that the developed code is efficient and the proposed rotating
bias field EMAT is feasible for inspecting delamination defect in thin
multilayer tubes. In addition, an experiment was carried out to investigate
the influence of the rotating speed on the EMAT signals. It is found that a
normal rotation speed does not give significant influence on the EMAT
signals, which further support the validity of the rotating bias field EMAT.
