Depth evaluation of surface-breaking cracks using laser-generated transmitted Rayleigh waves

Moura, André; Lomonosov, Alexey M.; Hess, Peter

doi:10.1063/1.2910897

Cited by 50 publications

(17 citation statements)

References 14 publications

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“…piezoelectric) transducer approach, using non-contact transducers, or a combination of both [7,13,15,16]. In the contact approach, contact with the sample under test and the use of couplant is required.…”

Section: Interaction Of Rayleigh Waves and Surface Defectsmentioning

confidence: 99%

In-plane and out-of-plane measurements of Rayleigh waves using EMATs for characterising surface cracks

Rosli

Edwards

Yang

2012

NDT & E International

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Electromagnetic acoustic transducers (EMATs) have been used to measure the properties of Rayleigh waves in the vicinity of defects propagating at different angles to the sample surface, which are more representative of real defects than slots machined normal to the surface. Transmission measurements show that one must consider the angle of the defect when choosing a depth calibration curve. We propose a procedure for crack characterisation (depth, angle) that considers transmission alongside measurements of both the in-plane and out-of-plane velocity components of the Rayleigh wave in the near-field of a defect, where the signal is enhanced due to constructive interference of incident and reflected wavemodes, and/or mode conversion.This procedure uses image analysis of B-Scans alongside the ratio of the enhancement in the in-plane to the out-of-plane components to characterise the angle. Once this is known the correct transmission depth calibration curve can be used. The procedure shows very good agreement between the measured and the actual slot characteristics on test samples.

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Section: Interaction Of Rayleigh Waves and Surface Defectsmentioning

confidence: 99%

In-plane and out-of-plane measurements of Rayleigh waves using EMATs for characterising surface cracks

Rosli

Edwards

Yang

2012

NDT & E International

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“…With regard to ultrasound inspection methods, this has led to numerous measurement and analysis approaches involving many decades of research and development. Recent advances in ultrasonic sensor probes [2,3], practical numerical models [4,5], and innovative analysis methods [6,7] have led to QNDE capabilities for crack characterization with significantly improved measurement capabilities and accuracies [2][3][4][5][6][7], where the 2-D and 3-D reconstruction of cracks and other damage features is becoming possible.…”

Section: Introductionmentioning

confidence: 99%

Surface-Breaking Crack Depth Assessment Using Near-Field Surface Acoustic Wave Signal Response

Blackshire¹,

Modic²

2011

AIP Conference Proceedings

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A method for determining the local depth of a surface-breaking crack is presented based on near-field surface acoustic wave signal responses. Finite element models were used to study the forward problem, where the characteristic response of a surface acoustic wave incident on a surface-breaking crack oriented normal to the material surface was investigated. Experimental validation of the modeling predictions was accomplished using a wedge transducer for surface wave generation and a scanning laser vibrometry system for surface wave detection. The characteristic nearfield amplitude response in reflection and in transmission showed several unique features, which are attributed to the superposition of incident, transmitted, reflected, and scattered energy fields. In the d/lambda range of 0.1 -0.8, an approximate linear trend was observed, which provides an opportunity to characterize and quantify local crack depth based on a simple linear inversion method. Finite element and experimental evidence of this effect are presented for surface-breaking slots with depths between 300um to 450um.

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“…This simplified phenomenological description of the proportionalities neglects material related phenomena like anisotropy, which may help to solve the problem. For some cases, like the influence of the depth of cracks on Rayleigh waves, the problem can be solved (two-dimensionally) and the geometrical features can be reconstructed [28].…”

Section: General Considerationsmentioning

confidence: 99%

“…The surface deviations caused by the ultrasound waves modulate the frequency of a probe-laser. The detection-scheme behind the probe-laser can be a designed Fabry-Perot-cavity to filter the sidebands or a Vibrometer [18,20,28].…”

Section: Laser-generated Ultrasoundmentioning

confidence: 99%

Novel trends in optical non-destructive testing methods

Huke

Klattenhoff

Kopylow

et al. 2013

J. Eur. Opt. Soc.-Rapid Publ.

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Non-destructive testing (NDT) describes a wide range of methods for measuring and comparing physical quantities against a nominal condition. In this paper we describe and compare different optical NdT (ONDT)-methods with respect to their characteristics and capability for different measurement tasks. ONDT may be specified in two categories, passive and active. The NDT principles of the first category just use a measurement method like view inspection, elipsometry or reflectometry to detect defects which are easily accessible. The principles of the second category use an excitation force, such as heat or mechanical vibration introduced by transducers to detect hidden defects. This category can be specified into two subcategories. The first subcategory "time-/depth-resolved" includes measurement methods delivering detailed information of the geometric features of a hidden defect. Therefore the excitation of the material and the detection of the reaction have to provide a time step which enables depth-solved measurements. Phase-resolved thermography and laser ultrasound are examples for this category. The second subcategory "Integrating" includes measurement technique coupled with an excitation that enables detection of defects but not evaluation of their geometric features. Examples for these measurement techniques are shearography, reflectometry, vibrometry and thermography coupled with excitation method like simple heating or loading with a constant force. We demonstrate experimental results obtained using methods developed in our institute and highlight directions of further development.

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Depth evaluation of surface-breaking cracks using laser-generated transmitted Rayleigh waves

Cited by 50 publications

References 14 publications

In-plane and out-of-plane measurements of Rayleigh waves using EMATs for characterising surface cracks

In-plane and out-of-plane measurements of Rayleigh waves using EMATs for characterising surface cracks

Surface-Breaking Crack Depth Assessment Using Near-Field Surface Acoustic Wave Signal Response

Novel trends in optical non-destructive testing methods

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