A rapid, fully non-contact, hybrid system for generating Lamb wave dispersion curves

Harb, Mohammad; Fang, Yuan

doi:10.1016/j.ultras.2015.03.006

Cited by 60 publications

(44 citation statements)

References 17 publications

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“…The laser beam is fixed and focused on a retroreflective tape 100 mm away from the excited region. The size of the excitation region ranges between 7.4 mm and 17.4 mm for excited signals with center frequency 60 kHz and 140 kHz using the focused transducer and between 26 mm and 32 mm using the non-focused transducer at a distance of 76 mm from the plate [14]. The plate used is AS4/3502 graphite epoxy composite laminate with [±45/0 2 ] 2S stacking sequence and dimensions 685 mm Â 685 mm Â 2.28 mm.…”

Section: Hybrid Ndi Systemmentioning

confidence: 99%

“…This method has been investigated previously by other researchers in metallic or composite structures [11,12], but in this study Morlet wavelet transform (MWT) was used to automatically process the received Lamb wave signals in order to enhance the precision of time-of-flight as described in the previous work by the same research group [7,14].…”

Section: A 0 Mode Dispersion Curvesmentioning

confidence: 99%

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Non-contact ultrasonic technique for Lamb wave characterization in composite plates

Harb

Fang

2016

Ultrasonics

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Section: Hybrid Ndi Systemmentioning

confidence: 99%

Section: A 0 Mode Dispersion Curvesmentioning

confidence: 99%

Non-contact ultrasonic technique for Lamb wave characterization in composite plates

Harb

Fang

2016

Ultrasonics

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“…Harb and Yuan [16,17] presented a noncontact technique using an air-coupled transducer (ACT) to generate the wave mode on the plate and an LSV to acquire the propagating mode. The technique requires precise control of the incidence angle of the ultrasonic pressure from the ACT upon the surface.…”

Section: Introductionmentioning

confidence: 99%

Calculation of Guided Wave Dispersion Characteristics Using a Three-Transducer Measurement System

Crespo

Courtney²

2018

Applied Sciences

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Featured Application: Rapid generation of dispersion curves for guided wave applications when knowledge of the material properties and thickness of the structure to be inspected are unknown.Abstract: Guided ultrasonic waves are of significant interest in the health monitoring of thin structures, and dispersion curves are important tools in the deployment of any guided wave application. Most methods of determining dispersion curves require accurate knowledge of the material properties and thickness of the structure to be inspected, or extensive experimental tests. This paper presents an experimental technique that allows rapid generation of dispersion curves for guided wave applications when knowledge of the material properties and thickness of the structure to be inspected are unknown. The technique uses a single source and measurements at two points, making it experimentally simple. A formulation is presented that allows calculation of phase and group velocities if the wavepacket propagation time and relative phase shift can be measured. The methodology for determining the wavepacket propagation time and relative phase shift from the acquired signals is described. The technique is validated using synthesized signals, finite element model-generated signals and experimental signals from a 3 mm-thick aluminium plate. Accuracies to within 1% are achieved in the experimental measurements.

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“…Numerous studies on Lamb wave applications to detect damage in large structures such as airplanes, factories, and ships are underway. Lamb wave generation techniques can be divided into two main categories: those using a contact-type device (e.g., piezoelectric zirconate titanate) [8][9][10][11][12][13][14][15][16][17][18][19][20][21] and those using a non-contact type device [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38] . Damage detection using a contact-type device seems inefficient, but inserting the device into a target structure can improve the efficiency.…”

Section: Introductionmentioning

confidence: 99%

“…Non-contact type devices include air-coupled transducers [37,38] and laser thermoelasticities [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36] . The former involves placing an air-coupled transducer near the Lamb wave generation point on the target structure, and the vibration of the transducer is transmitted through the medium (air in this case).…”

Section: Introductionmentioning

confidence: 99%

Non-contact and non-destructive Lamb wave generation using laser-induced plasma shock wave

Hosoya

Yoshinaga

Kanda

et al. 2018

International Journal of Mechanical Sciences

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a b s t r a c tThis paper proposes a non-contact and non-destructive method to generate Lamb waves against a target structure using the impulse excitation force generated by laser-induced plasma (LIP). When a high power pulse laser is irradiated in air and its laser fluence exceeds 10 15 W/m 2 , a plasma is formed. While the plasma in air expands in high speed, shock waves on the spherical surface are generated and these shock waves become the impulse excitation force against a target structure, resulting in the non-contact and non-destructive approach. A 2024 aluminum alloy plate is used as the test piece in the experiment, and the dynamic characteristics of the Lamb waves generated from LIP shock waves are measured. Phase velocity and group velocity of generated Lamb waves were compared to the calculated values from Rayleigh-Lamb frequency equations and we found that maximum error was 5% and its frequency component included at least 400 kHz. Further, we investigated the relationship between the distance from the LIP shock wave-generating location to a test piece and the dynamic characteristics of the generated Lamb waves. This method can control the amplitude and the frequency components of generated Lamb waves by changing this distance.

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A rapid, fully non-contact, hybrid system for generating Lamb wave dispersion curves

Cited by 60 publications

References 17 publications

Non-contact ultrasonic technique for Lamb wave characterization in composite plates

Non-contact ultrasonic technique for Lamb wave characterization in composite plates

Calculation of Guided Wave Dispersion Characteristics Using a Three-Transducer Measurement System

Non-contact and non-destructive Lamb wave generation using laser-induced plasma shock wave

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