Analysis of wavelength deviation of guided waves with electromagnetic acoustic transducers

2012 ◽  
Vol 112 (8) ◽  
pp. 084913 ◽  
Author(s):  
Guofu Zhai ◽  
Tao Jiang ◽  
Lei Kang
Keyword(s):  
Guided Waves ◽  
Electromagnetic Acoustic Transducers ◽  
Acoustic Transducers

Flaw Detection in Aluminum Plate by Shear Horizontal Guided Wave Based on Magnetostriction EMAT

2014 ◽  
Vol 614 ◽  
pp. 287-290
Author(s):  
Le Chen ◽  
Yue Min Wang ◽  
Hai Quan Geng
Keyword(s):  
Guided Waves ◽  
Flaw Detection ◽  
Test Sample ◽  
Guided Wave ◽  
Sh Waves ◽  
Electromagnetic Acoustic Transducers ◽  
Acoustic Transducers ◽  
Non Destructive ◽  
Viable Method ◽  
Shear Horizontal

Shear horizontal (SH) guided waves have been proved to be a viable method in the Non-Destructive Evaluation (NDE). Electromagnetic acoustic transducers (EMAT) can excite SH waves easily. By bonding the Fe-Co alloy to the test sample, the SH guided waves based on magnetostriction effect can be used to detect the flaw in nonferromagnetic material. The principle of exciting and receiving SH waves is introduced, and an experiment is carried out to validate the result.

scholarly journals Pure SH1 Guided-Wave Generation Method with Dual Periodic-Permanent-Magnet Electromagnetic Acoustic Transducers for Plates Inspection

Sensors ◽  
2019 ◽  
Vol 19 (13) ◽  
pp. 3019 ◽  
Author(s):  
Gongzhe Qiu ◽  
Xiaochun Song ◽  
Xu Zhang ◽  
Jun Tu ◽  
Tao Chen
Keyword(s):  
Permanent Magnet ◽  
Guided Waves ◽  
Simulation Analysis ◽  
Guided Wave ◽  
Enhancement Effect ◽  
Large Area ◽  
Suppression Effect ◽  
Electromagnetic Acoustic Transducers ◽  
Positioning Errors ◽  
Acoustic Transducers

High frequency guided-waves offer a trade-off between the high sensitivity of local bulk ultrasonic thickness measurements and the large area scanning of lower frequency guided-waves, so it has been a growing interest for corrosion inspection with the dispersive SH1 mode. However, according to the dispersive curve, it is hard to generate the pure SH1 mode since the non-dispersive SH0 mode will be excited simultaneously. Thus, this paper investigates a transducer design method to generate a pure SH1 guided-wave, where the dual periodic-permanent-magnet electromagnetic acoustic transducers (PPM EMATs) are placed on exactly opposite positions either side of the plate symmetrically. The suppression effect for SH0 and the enhancement effect for SH1 of the dual PPM EMATs are mainly discussed by theoretical analysis and simulation analysis, and the influence of positioning errors of PPM EMATs placed on opposite sides of the plate on its performances are analyzed. Employing the proposed dual PPM EMATs, some experiments are performed to verify the reliability of finite element simulation. The results indicate that the dual PPM EMATs can suppress the SH0 mode and generate the pure SH1 mode effectively. Moreover, the longitudinal and lateral positioning errors can affect the dual PPM EMATs performances significantly.

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