Imaging wall thinning defect by electromagnetic ultrasonic shear horizontal guided wave tomography

2016 ◽  
Vol 52 (1-2) ◽  
pp. 323-330
Author(s):  
Weibin Li ◽  
Younho Cho
Keyword(s):  
Guided Wave ◽  
Wall Thinning ◽  
Wave Tomography ◽  
Ultrasonic Shear ◽  
Shear Horizontal

Shear Horizontal Guided Wave Corrosion Detection and Quantification in Pipes via Linear Scanning Magnetostrictive Transducers (MST)

2021 ◽  
Author(s):  
Xin Chen ◽  
Sergey Vinogradov ◽  
Adam Cobb
Keyword(s):  
Guided Waves ◽  
Guided Wave ◽  
Outer Diameter ◽  
Corrosion Detection ◽  
Promising Tool ◽  
Wall Thinning ◽  
Synthetic Aperture Focusing ◽  
Shear Horizontal ◽  
Detection And Quantification ◽  
Linear Scanning

Abstract Shear horizontal (SH) guided waves are being widely considered as a promising tool for locating wall thinning corrosion in pipelike structures. One established approach to excite such waves in pipes is through the magnetostrictive transducers (MsT), which is an electromagnetic-based guided wave transducer that offers unique advantages over other transducer types. A common practice for fast screening of defects is using an automated probe positioning system. In this paper, we report the usage of a newly designed linear scanning MsT, where an iron cobalt (FeCo) strip of a predefined length wound with radio frequency (RF) coils is attached to the testing structure using shear wave couplants and a moving permanent magnet driven by a stepper motor is used to excite SH guided waves at predefined positions. In this fashion, manual manipulation of probe is minimized which significantly increases testing speed. The performance of the linear scanning MsT at corrosion inspection is evaluated experimentally by introducing “V” shaped gradual wall thinning patches of different depths and locations on a 406 mm outer diameter (OD) steel pipe with 10 mm wall thickness. The reflection and transmission amplitudes of SH modes, as well as indications from B-scan and synthetic aperture focusing technique (SAFT) images, are extracted for corrosion detection and quantification. Numerical modeling is also conducted to facilitate the understanding of SH waves interaction with defects.

scholarly journals High-resolution thickness maps of corrosion using SH1 guided wave tomography

2021 ◽  
Vol 477 (2245) ◽  
pp. 20200380
Author(s):  
Andreas A. E. Zimmermann ◽  
Peter Huthwaite ◽  
Brian Pavlakovic
Keyword(s):  
Petrochemical Industry ◽  
Guided Waves ◽  
Corrosion Damage ◽  
Wave Mode ◽  
Guided Wave ◽  
Resolution Limit ◽  
First Order ◽  
Wave Tomography ◽  
Plane Direction ◽  
Shear Horizontal

Quantifying corrosion damage is vital for the petrochemical industry, and guided wave tomography can provide thickness maps of such regions by transmitting guided waves through these areas and capturing the scattering information using arrays. The dispersive nature of the guided waves enables a reconstruction of wave velocity to be converted into thickness. However, existing approaches have been shown to be limited in in-plane resolution, significantly short of that required to accurately image a defect target of three times the wall thickness (i.e. 3 T) in each in-plane direction. This is largely due to the long wavelengths of the fundamental modes commonly used, being around 4 T for both A0 and S0 at the typical operation points. In this work, the suitability of the first-order shear-horizontal guided wave mode, SH1, has been investigated to improve the resolution limit. The wavelength at the desired operating point is significantly shorter, enabling an improvement in resolution of around 2.4 times. This is first verified by realistic finite-element simulations and then validated by experimental results, confirming the improved resolution limit can now allow defects of maximum extent 3T-by-3T to be reliably detected and sized, i.e. a long-pursued goal of guided wave tomography has been achieved.

Measurement of the viscosity–density product using multiple reflections of ultrasonic shear horizontal waves

Ultrasonics ◽  
2006 ◽  
Vol 44 ◽  
pp. e1031-e1036 ◽  
Author(s):  
Margaret S. Greenwood ◽  
Justus D. Adamson ◽  
Leonard J. Bond
Keyword(s):  
Multiple Reflections ◽  
Ultrasonic Shear ◽  
Shear Horizontal

Accurate Thickness Inversion of Corrosion Using A1 Lamb Wave

2021 ◽  
Author(s):  
Min Lin ◽  
Yang Liu
Keyword(s):  
High Resolution ◽  
Oil And Gas ◽  
Residual Life ◽  
Early Stage ◽  
Corrosion Damage ◽  
Oil And Gas Industry ◽  
Forward Modeling ◽  
Guided Wave ◽  
Velocity Inversion ◽  
Wave Tomography

Abstract Corrosion is one of the most critical issues in the oil and gas industry, leading to severe environmental and economic problems. Due to the high cost and serious safety risk of corrosion, it is essential to improve current corrosion testing techniques to detect corrosion damages at an early stage. Guided wave tomography (GWT) demonstrates its great potential to inspect and quantify the corrosion damage. GWT is capable of determining the residual life of corrosion structures by quantifying the remaining wall thickness. In this paper, an accurate guided wave tomography technique incorporating full waveform inversion (FWI) and higher-order Lamb waves (A1 mode) is presented for plate-like structures, which is able to get high-resolution reconstruction results. The technique consists of three steps: forward modeling, velocity inversion and thickness reconstruction. The forward modeling is computed by solving the elastic full-wave equations in 2-D time domain by using the finite difference method. High-resolution phase velocity inversion can then be obtained by minimizing the waveform misfit function between simulated and recorded data using a second order optimization method, which updates the velocity model from low to high frequencies iteratively. Finally, the velocity variations can be transformed into depth profiles by using the dispersive characteristics of ultrasonic guided waves; therefore, the thickness reconstruction can be obtained. The numerical simulations are performed on an aluminum plate with a complicated corrosion defect. By comparing the thickness reconstruction maps using both A1 and A0 modes, the results demonstrate that FWI with A1 mode can achieve significantly better resolution of corrosion imaging than that with A0 mode.

Field trials results of guided wave tomography

2015 ◽  
Author(s):  
Arno Volker ◽  
Tim van Zon ◽  
Edwin van der Leden
Keyword(s):  
Field Trials ◽  
Guided Wave ◽  
Wave Tomography
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