Influence of the Lift-Off Effect on the Cut-Off Frequency of the EMAT-Generated Rayleigh Wave Signal

被引：16

作者：

Yi, Pengxing ^{[1
]}

Zhang, Kang ^{[1
]}

Li, Yahui ^{[1
]}

Zhang, Xuming ^{[2
]}

机构：

[1] Huazhong Univ Sci & Technol, Sch Mech Sci & Engn, Wuhan 430074, Peoples R China

[2] Huazhong Univ Sci & Technol, Sch Life Sci & Technol, Wuhan 430074, Peoples R China

来源：

SENSORS | 2014年 / 14卷 / 10期

基金：

国家高技术研究发展计划(863计划);

关键词：

EMAT; cut-off frequency; rayleigh wave; lift-off; ELECTROMAGNETIC ACOUSTIC TRANSDUCERS; GUIDED-WAVES; PERFORMANCE; DEFECTS; INPLANE; MODEL;

D O I：

10.3390/s141019687

中图分类号：

O65 [分析化学];

学科分类号：

070302 ; 081704 ;

摘要：

The electromagnetic acoustic transducer (EMAT), a non-contact NDT tool with large lift-off, is becoming an attractive method for detecting the cracks in the metal parts. However, the lift-off of the transducer has a direct effect on the feature that is used to characterize the defects. A detailed investigation on the relationship between the feature and the lift-off of the EMAT is crucial in the detection process. This paper investigates the lift-off effect on the feature, cut-off frequency of EMAT in the Rayleigh wave. The study can be divided into two parts. Firstly, with a multi-field coupling environment, 2-D electromagnetic and wave generation EMAT models are built to simulate the interaction of the Rayleigh wave with the surface crack. Then, the lift-off effect on the cut-off frequency is investigated through simulation and experiment. Compared to the previous studies, it is found that lift-off would cause a negative result when the lift-off varies in the testing process. Besides, the calibration obtained from the tests at a random lift-off value can be used in other tests with any different lift off value provided that the lift-off is kept as a constant during the detection process.

引用

页码：19687 / 19699

页数：13

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