State Key Laboratory for Strength and Vibration of Mechanical Structures, Shaanxi Engineering Research Center of NDT and Structural Integrity Evaluation, School of Aerospace Engineering, Xi'an Jiaotong University, Xi'an 710049, China.
Leading Edge NDT Technology (LENDT) Group, Malaysian Nuclear Agency, Bangi, Kajang 43000, Malaysia.
Sensors (Basel). 2018 May 28;18(6):1733. doi: 10.3390/s18061733.
For fuel transmission and structural strengthening, small-diameter pipes of nonmagnetic materials are extensively adopted in engineering fields including aerospace, energy, transportation, etc. However, the hostile and corrosive environment leaves them vulnerable to external corrosion which poses a severe threat to structural integrity of pipes. Therefore, it is imperative to nondestructively detect and evaluate the external corrosion in nonmagnetic pipes. In light of this, a capsule-type Electromagnetic Acoustic Transducer (EMAT) for in-situ nondestructive evaluation of nonmagnetic pipes and fast screening of external corrosion is proposed in this paper. A 3D hybrid model for efficient prediction of responses from the proposed transducer to external corrosion is established. Closed-form expressions of field quantities of electromagnetics and EMAT signals are formulated. Simulations based on the hybrid model indicate feasibility of the proposed transducer in detection and evaluation of external corrosion in nonmagnetic pipes. In parallel, experiments with the fabricated transducer have been carried out. Experimental results are supportive of the conclusion drawn from simulations. The investigation via simulations and experiments implies that the proposed capsule-type EMAT is capable of fast screening of external corrosion, which is beneficial to the in-situ nondestructive evaluation of small-diameter nonmagnetic pipes.
在航空航天、能源、交通等工程领域，广泛采用小直径的非磁性材料管道来进行燃料输送和结构强化。然而，恶劣和腐蚀性的环境使它们容易受到外部腐蚀的影响，这对管道的结构完整性构成了严重威胁。因此，对非磁性管道的外部腐蚀进行无损检测和评估势在必行。针对这一问题，本文提出了一种用于非磁性管道原位无损评估和外部腐蚀快速筛选的胶囊式电磁声换能器（EMAT）。建立了一个用于有效预测该换能器对外界腐蚀响应的三维混合模型。推导出了电磁场和 EMAT 信号的解析表达式。基于混合模型的仿真结果表明了该换能器在检测和评估非磁性管道外部腐蚀方面的可行性。同时，还进行了制作好的换能器的实验。实验结果支持了从仿真中得出的结论。通过仿真和实验的研究表明，所提出的胶囊式 EMAT 能够快速筛选外部腐蚀，有利于对小直径非磁性管道进行原位无损评估。
