Inspection of notch depths in thin structures using transmission coefficients of laser-generated Lamb waves

Lei, Yongmei; Ume, I. Charles

doi:10.1016/j.ultras.2015.07.004

Cited by 15 publications

(6 citation statements)

References 15 publications

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“…In addition, noncontact methods reduce any extra labor and time required for installation and maintenance of traditional contact transducers, while also diminishing the use of consumables. As was mentioned in the previous section “Ultrasonic monitoring techniques,” the commonly used noncontact type transducers are EMATs, 134 PL, 135–138 and ACT. 120 EMATs generally cannot be applied to composite materials and are limited to metallic/magneto-strictive structures as these conductive structures allow the traveling of eddy current on their surface generated by the AC current in the electric coil.…”

Section: Fully Noncontact Air-coupled Utmentioning

confidence: 99%

Noncontact nondestructive ultrasonic techniques for manufacturing defects monitoring in composites: a review

Mortada,

El Mousharrafie,

Mahfoud

et al. 2023

Structural Health Monitoring

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Composite materials are widely used in most industries due to their high specific strength, specific stiffness, and their relatively lighter weight compared to other traditional materials. However, the presence of defects arising from manufacturing processes or during service loads can make these structures more susceptible to a diminished performance. Furthermore, the former defects are inevitable in composite structures, but they can be reduced. Each type of defect requires specific inspection techniques and configurations. In this work, a review of the different types of composites manufacturing processes and their corresponding resultant defects is presented with the various nondestructive evaluation techniques employed for these defects’ characterization. The emphasis of this paper is on ultrasonic inspection and detection techniques for they present high sensitivity to surface/subsurface discontinuities, superior depth of ultrasonic penetration for flaw detection, feasibility on large scales, and instantaneous and detailed images production. Notably, noncontact ultrasonic testing techniques are also reviewed, air-coupled techniques in specific, and highlighted as a fine alternative to conventional contact inspection systems as they reduce the restrictions that coexist with the use of couplants. Moreover, these ultrasonic testing techniques are summarized to show the latest research progress achieved in the field of air-coupled ultrasonic inspection systems for manufacturing defects’ monitoring in composite structures including delamination, porosity, dryness, waviness, and resin lack/excess. Finally, we highlight the type and central frequency of the transducers and experimental results present in literature and obtained in terms of both detection and size of the defects.

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Section: Fully Noncontact Air-coupled Utmentioning

confidence: 99%

Noncontact nondestructive ultrasonic techniques for manufacturing defects monitoring in composites: a review

Mortada,

El Mousharrafie,

Mahfoud

et al. 2023

Structural Health Monitoring

View full text Add to dashboard Cite

show abstract

“…LeiYangI. CharlesUme [19] are used CWT for a thin steel plate in order to calculate the transmission coefficients of laser-generated Lamb waves. Taoufiq Belhoussine Drissi et al [20] are used the wavelet transform for a speech signal in order to determine the choice of the appropriate wavelet analyzer with the method of extraction of MFCC coefficients for an assistance in the diagnosis of Parkinson's disease.…”

Section: Pablo R Souza and Euripedes G O Nobregamentioning

confidence: 99%

“…Tsun-Yen Wu [21] et al are used the CWT to help identify wave packets of the S 0 and A 0 Lamb wave modes in order to detect defects in thin structures. Lei Yang, I et al [22] are used the LEU technique to inspect the notch depths in thin steel plates and by the CWT they computed the transmission coefficient of Laser generated Lamb wave.…”

Section: Pablo R Souza and Euripedes G O Nobregamentioning

confidence: 99%

Post Treatment of Guided Wave by using Wavelet Transform in the Presence of a Defect on Surface

Rachid¹,

Houda²,

Taoufiq³

et al. 2019

IJACSA

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This article presents a Lamb wave processing by using two methods: Fast Fourier Transform (FFT2D) and Continuous Wavelet Transform (CWT) using Morlet wavelet. This treatment is done for a structure of two aluminum-copper plates, which are in contact edge to edge of a perpendicular junction with a thickness "e" in the presence of a rectangular and symmetrical defect located on the surface of the junction with a depth "d". The aim under this study is to calculate the transmission and reflection energy coefficients by the two methods. The results of simulation obtained by Comsol software of an incident wave S 0 at F = 800 kHz indicate us a good coherence between the two methods (FFT2D and CWT).

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“…Ultrasonic guided Lamb waves are already widely used for the non-destructive testing and evaluation of pipes, thin plates and films [6,7,8,9,10,11,12,13]. Their propagation characteristics are sensitive to structural changes in the material through which they travel.…”

Section: Introductionmentioning

confidence: 99%

Attenuation of a Slow Subsonic A0 Mode Ultrasonic Guided Wave in Thin Plastic Films

et al. 2019

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The ultrasonic testing technique using Lamb waves is widely used for the non-destructive testing and evaluation of various structures. For air-coupled excitation and the reception of A0 mode Lamb waves, leaky guided waves are usually exploited. However, at low frequencies (<100 kHz), the velocity of this mode in plastic and composite materials can become slower than the ultrasound velocity in air, and its propagation in films is accompanied only by an evanescent wave in air. To date, the information about the attenuation of the slow A0 mode is very contradictory. Therefore, the objective of this investigation was the measurement of the attenuation of the slow A0 mode in thin plastic films. The measurement of the attenuation of normal displacements of the film caused by a propagating slow A0 mode is discussed. The normal displacements of the film at different distances from the source were measured by a laser interferometer. In order to reduce diffraction errors, the measurement method based on the excitation of cylindrical but not plane waves was proposed. The slow A0 mode was excited in the polyvinylchloride film by a dry contact type ultrasonic transducer made of high-efficiency PMN-32%PT strip-like piezoelectric crystal. It was found that that the attenuation of the slow A0 mode in PVC film at the frequency of 44 kHz is 2 dB/cm. The obtained results can be useful for the development of quality control methods for plastic films.

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Inspection of notch depths in thin structures using transmission coefficients of laser-generated Lamb waves

Cited by 15 publications

References 15 publications

Noncontact nondestructive ultrasonic techniques for manufacturing defects monitoring in composites: a review

Noncontact nondestructive ultrasonic techniques for manufacturing defects monitoring in composites: a review

Post Treatment of Guided Wave by using Wavelet Transform in the Presence of a Defect on Surface

Attenuation of a Slow Subsonic A0 Mode Ultrasonic Guided Wave in Thin Plastic Films

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