Edge and Notch Detection in a Plate Using Time Reversal Process of Leaky Lamb Waves

Vallée, Jean-Christophe; Ploix, Marie-Aude; Baqué, F.; Cavaro, Matthieu; Chaix, Jean François

doi:10.3390/app12010228

Cited by 3 publications

(1 citation statement)

References 31 publications

(48 reference statements)

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“…Both assumptions are useful to simplify signal analysis making possible to isolate the main propagation mode and observe the effect of the defect in its dispersion curve. In addition, with a single excitation point, Lamb waves can cover long distances with a good signal-to-noise ratio [10]. Considering delaminations the most critical and common type of defects [11], these features make the propagation of Lamb waves the foundation of the current non-destructive testing (NDT) techniques based on laser vibrometry.…”

Section: Introductionmentioning

confidence: 99%

A wavefront track approach to defect detection in composites by scanning laser Doppler vibrometry

Candelaresi,

Annessi,

Allevi

et al. 2024

J. Phys.: Conf. Ser.

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Composite laminates are becoming increasingly popular in a large variety of applications due to their favourable mechanical properties. However, laminates production processes can lead to various defects in the final material. The most common type is related to thickness variations, e.g. delaminations between layers, which can compromise the mechanical strength of the structure. Therefore, there is a great interest in developing non-destructive and non-contact quality control techniques for composite material assessment to minimize process costs. An interesting approach is the use of laser Doppler vibrometry combined with signal analysis based on Lamb waves propagation. In this work, we used an impulsive force given by a piezoelectric disk to the specimen and a laser Doppler vibrometer acquiring the points velocity over time along a scanning grid on the surface. The specimen is a fiberglass reinforced flat panel with seven different orientated layers which presents a delamination of about 22 mm. The maximum thickness-frequency product achieved in this analysis has been 0.2 MHz∙mm. In contrast to state-of-the-art methods for identifying thickness variation based on local estimation of the principal wave number, the proposed algorithm makes use of a tracking filter of the wave front of the propagating A0 mode waves, returning a final image in polar coordinates. The final information given by the algorithm provides the position of the delamination and, hence, can be used as a pass/failure test. State-of-the-art methods are also able to identify the shape of the defect but pay the price of a higher computational cost by using at least 4D matrix processing unlike our method which only uses 3D matrices.

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Section: Introductionmentioning

confidence: 99%

A wavefront track approach to defect detection in composites by scanning laser Doppler vibrometry

Candelaresi,

Annessi,

Allevi

et al. 2024

J. Phys.: Conf. Ser.

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A new methodology of non-destructive testing in a set of two parallel immersed plates using time reversal process and leaky Lamb waves

Vallée,

Ploix,

Cavaro

et al. 2024

NDT & E International

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Micro-Sized Pinhole Inspection with Segmented Time Reversal and High-Order Modes Cluster Lamb Waves Based on EMATs

Zhou

Yang²,

Li³

et al. 2023

Chin. J. Mech. Eng.

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Pinhole corrosion is difficult to discover through conventional ultrasonic guided waves inspection, particularly for micro-sized pinholes less than 1 mm in diameter. This study proposes a new micro-sized pinhole inspection method based on segmented time reversal (STR) and high-order modes cluster (HOMC) Lamb waves. First, the principle of defect echo enhancement using STR is introduced. Conventional and STR inspection experiments were conducted on aluminum plates with a thickness of 3 mm and defects with different diameters and depths. The parameters of the segment window are discussed in detail. The results indicate that the proposed method had an amplitude four times larger than of conventional ultrasonic guided waves inspection method for pinhole defect detection and could detect micro-sized pinhole defects as small as 0.5 mm in diameter and 0.5 mm in depth. Moreover, the segment window location and width (5−10 times width of the conventional excitation signal) did not affect the detection sensitivity. The combination of low-power and STR is more conducive to detection in different environments, indicating the robustness of the proposed method. Compared with conventional ultrasonic guided wave inspection methods, the proposed method can detect much smaller defect echoes usually obscured by noise that are difficult to detect with a lower excitation power and thus this study would be a good reference for pinhole defect detection.

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Edge and Notch Detection in a Plate Using Time Reversal Process of Leaky Lamb Waves

Cited by 3 publications

References 31 publications

A wavefront track approach to defect detection in composites by scanning laser Doppler vibrometry

A wavefront track approach to defect detection in composites by scanning laser Doppler vibrometry

A new methodology of non-destructive testing in a set of two parallel immersed plates using time reversal process and leaky Lamb waves

Micro-Sized Pinhole Inspection with Segmented Time Reversal and High-Order Modes Cluster Lamb Waves Based on EMATs

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