Development of a wholly flexible surface wave electromagnetic acoustic transducer for pipe inspection

2020 ◽  
Vol 62 (1) ◽  
pp. 13-29 ◽  
Author(s):  
Zenghua Liu ◽  
Aili Li ◽  
Bin Wu ◽  
Cunfu He
Keyword(s):  
Surface Wave ◽  
Pipe Inspection ◽  
Electromagnetic Acoustic Transducer ◽  
Acoustic Transducer ◽  
Flexible Surface

Numerical Study of Detection of Crack on Corroded Rough Surface Using EMAT-Generated Surface Wave

2021 ◽  
Author(s):  
Zhe Wang ◽  
Xuedong Chen ◽  
Zhichao Fan ◽  
Wei Chen ◽  
Jingwei Cheng ◽  
...  
Keyword(s):  
Surface Wave ◽  
Rough Surface ◽  
Numerical Study ◽  
Element Model ◽  
Center Frequency ◽  
Detection Accuracy ◽  
Electromagnetic Acoustic Transducer ◽  
Acoustic Surface Wave ◽  
Excitation Region ◽  
Acoustic Transducer

Abstract Electromagnetic acoustic transducer (EMAT) gradually becomes the main excitation method for surface wave, which is suitably used in periodic inspection or long-term monitoring of pressure equipment. However, the corroded surfaces appearing on the pressure pipes and vessels can cause an increase of background noise and remarkable attenuation of the echo wave, which restrict the improvement of detection accuracy of surface crack. In this paper, a finite element model of EMAT-Generated surface wave inspection for steel plate with rough surface is established based on the constitutive equation of ferromagnetic materials. Considering the Lorentz force and magnetostrictive effect, the influences of rough surface on energy conversion of multiple fields in the excitation and propagation process of electromagnetic acoustic surface wave are separately investigated. The surface wave responses of cracks characterized by rectangular groove on corroded rough surface have been analyzed further. The numerical results indicate that the rough surface of the excitation region below the transducer with a center frequency of 330 kHz has a slight effect on the surface wave energy, while the surface roughness of the propagation region attenuates echo signal of crack significantly. The reflection coefficients of echo signals can be utilized to quantitatively characterize the depth of crack on the corroded surface with roughness less than λ/15 (λ is wavelength of surface wave).

scholarly journals Characteristics of T(0, 1) Guided-Wave Point-Focusing Electromagnetic Acoustic Transducer for Pipe Inspection

2020 ◽  
Vol 20 (6) ◽  
pp. 2895-2903 ◽  
Author(s):  
Songling Huang ◽  
Hongyu Sun ◽  
Gongtian Shen ◽  
Baoxuan Wang ◽  
Qing Wang ◽  
...  
Keyword(s):  
Guided Wave ◽  
Pipe Inspection ◽  
Electromagnetic Acoustic Transducer ◽  
Acoustic Transducer
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