Measurement of shallow defects in metal plates using inter-digital transducer-based laser-scanning vibrometer

Ting, Kang; Moon, Seongin; Han, Sang Do; Jeon, Jun Young; Park, Gyuhae

doi:10.1016/j.ndteint.2018.11.004

Cited by 21 publications

(10 citation statements)

References 16 publications

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“…The IDT-based SLDV is introduced to measure shallow defects in a thick plate. 18 However, piezoelectric materials are very brittle, requiring coupling medium such as oil or water and so cannot simply pressed against the plate. So, a dry-coupled IDT can be fabricated into a practical, easily mounted, and detachable transducer.…”

Section: Measurement Of Thickness Of Plate Using Dry-coupled Idt-basementioning

confidence: 99%

“…This means that <10% wall-thinning detection technology is required to ensure safety of the containment. Therefore, Kang et al 18 recently developed a technique to detect shallow defects (<5%) using an interdigital transducer (IDT)based SLDV. The SLDV excites Lamb waves at high wave number sensitivity in the dispersion curve to detect the shallow defects in a plate.…”

Section: Introductionmentioning

confidence: 99%

“…12–17 However, referring to KEPIC 3521, “correction or evaluation requires pressure-retaining component corrosion or erosion that exceeds 10% of the nominal wall thickness.” This means that ≤10% wall-thinning detection technology is required to ensure safety of the containment. Therefore, Kang et al 18 recently developed a technique to detect shallow defects (≤5%) using an interdigital transducer (IDT)-based SLDV. The SLDV excites Lamb waves at high wave number sensitivity in the dispersion curve to detect the shallow defects in a plate.…”

Section: Introductionmentioning

confidence: 99%

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Measurement of defects in a plate using dry-coupled interdigital transducer–based scanning laser Doppler vibrometer

Ting

Han

Moon

et al. 2020

Structural Health Monitoring

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The interdigital transducer–based scanning laser Doppler vibrometer has recently been introduced to efficiently generate the symmetric mode for damage detection of shallow defects in thick plates. To measure shallow defects in a carbon steel plate, the excitation frequency is optimized based on the analysis of wavenumber sensitivity and degree of separation between modes. Even though the interdigital transducer–based scanning laser Doppler vibrometer method using continuous excitation is a promising method for visualizing defects in plate-like structures, the interdigital transducer has to be coupled to media, such as oil or water, to minimize the variation in acoustic impedance between the lead zirconium titanate and the plate-like structures. In this study, we develop a dry-coupled interdigital transducer–based scanning laser Doppler vibrometer system for the detection of shallow defects in a plate to facilitate easy mounting and demounting from the plate. To verify the proposed dry-coupled interdigital transducer–based scanning laser Doppler vibrometer, plates with four and eight different depth defects are introduced, and it is demonstrated that the defects in thick plates measured by dry-coupled interdigital transducer–based scanning laser Doppler vibrometer are visualized compared to those measured by interdigital transducer–based scanning laser Doppler vibrometer.

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Section: Measurement Of Thickness Of Plate Using Dry-coupled Idt-basementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Measurement of defects in a plate using dry-coupled interdigital transducer–based scanning laser Doppler vibrometer

Ting

Han

Moon

et al. 2020

Structural Health Monitoring

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“…Based on their results, Jeon et al proposed a local wavenumber mapping and 2D-wavelet wavenumber filtering approach for defect detection in composite structures. 21,22 Kang et al 25 developed an interdigital transducer (IDT)-based scanning laser Doppler vibrometer (SLDV) to detect shallow defects in plates 23,24 as well as a dry-coupled IDT-based SLDV that could be applied to a structure without the use of coupling materials. 25 Many of these approaches have shown that the wavenumber estimation method is suitable for representing the damage in plates and pipes.…”

Section: Introductionmentioning

confidence: 99%

Detection of shallow wall-thinning of pipes using a flexible interdigital transducer-based scanning laser Doppler vibrometer

Ting

Han

Kim

et al. 2022

Structural Health Monitoring

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Interdigital transducer (IDT)-based scanning laser Doppler vibrometers (SLDVs) have recently been developed to detect shallow defects in plates. An IDT-based SLDV was augmented with Lamb wave frequency fusion capability to enable the imaging of defects across the entire depth of a plate. Dry-coupled IDTs are a type of field-deployable IDT that do not require the attachment of a couplant to the structure. However, this technique is not applicable to the analysis of shallow wall thinning, because IDTs composed of lead zirconium titanate (PZT) cannot be attached to the curved surface of a structure. To address this issue, we developed a new type of IDT—the flexible IDT—that can be bent along the circumferential direction of a pipe. To set the gap spacing of the flexible IDT, the wavenumber sensitivity and minimum distance from the reference mode (MDRM) was calculated, and the S 0 mode is selected to ensure high-wavenumber sensitivity above the threshold of the MDRM. The proposed flexible IDT-based SLDV was tested by using it to visualize the wall thinning on pipes with 4%, 6%, and 20% thinning. The results of this study will contribute toward the development of systems that improve on existing planar laser scanning schemes and enable shallow defect detection in pipes using laser ultrasonics.

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“…Ultrasonic wavefield imaging has emerged in the last decade as a new NDE method, particularly, in the understanding of how ultrasonic guided waves propagate and interact with defects and structural features [4,5]. Multiple ultrasonic scanning techniques has been applied for the wavefield recording, we can mention, although the list is not inclusive: shearography [6], electronic pulse interferometry (ESPI) [7], air-coupled ultrasonic (ACU) [8,9] and laser Doppler vibrometry (LDV) [10].…”

Section: Introductionmentioning

confidence: 99%

Experimental Study of Lamb Waves Propagation inside an Impact Damage in the Size of the Used Wavelength

Taleb

Rittmeier

Sinapius

et al. 2020

Russ J Nondestruct Test

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The present work is an experimental study of Lamb waves propagation in an aluminum plate with an impact damage in the size of the S0 mode wavelength. The aim of this study is to visualize the wavefield near the defect in the case of extreme diffusion, as well as the interference of the modes inside of it and their transformation. The results were obtained by applying the continuous wavelet transform (CWT) on the wavefield data recorded by two ultrasonic scanning techniques: the air coupled ultrasonic (ACU) and the Laser doppler vibrometry (LDV), to obtain a C-scan and a B-scan of the plate respectively. Space-wavenumber representations showed the behavior of Lamb waves in the plate as well as the reduction in thickness of the impacted area. The width of the latter could be estimated and the modes present at each position of the plate could be identified.

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Measurement of shallow defects in metal plates using inter-digital transducer-based laser-scanning vibrometer

Cited by 21 publications

References 16 publications

Measurement of defects in a plate using dry-coupled interdigital transducer–based scanning laser Doppler vibrometer

Measurement of defects in a plate using dry-coupled interdigital transducer–based scanning laser Doppler vibrometer

Detection of shallow wall-thinning of pipes using a flexible interdigital transducer-based scanning laser Doppler vibrometer

Experimental Study of Lamb Waves Propagation inside an Impact Damage in the Size of the Used Wavelength

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