A laser–EMAT system for ultrasonic weld inspection

Dixon, S.; Edwards, Chris; Palmer, S.B.

doi:10.1016/s0041-624x(99)00002-5

Cited by 57 publications

(27 citation statements)

References 7 publications

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“…There are several previous examples in the published literature [16][17][18][19][20] of researchers using a pulsed laser to generate ultrasound which is subsequently detected using an EMAT. The EMAT has favourable sensitivity when compared to laser based interferometric detection [21], particularly where in-plane displacement measurements are measured.…”

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confidence: 99%

Detection of cracks in metal sheets using pulsed laser generated ultrasound and EMAT detection

et al. 2011

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A pulsed Nd:YAG laser with an approximately Gaussian beam shape is directed onto the surface of an aluminium sheet at an energy density below which damage by laser ablation occurs, generating Lamb waves in the sheet. The laser beam is raster scanned across the surface of the sample. The Lamb waves travel radially outwards from the generation point and are detected some distance away by an electromagnetic acoustic transducer with sensitivity to in-plane displacements of the sheet. A number of static EMATs are located around the edges of the sheet, some distance from the generation point.The presence of a crack-like defect on the sheet can be detected by either a sudden change in the ultrasonic waveform or by an enhancement in the frequency content of the waveform when the laser beam illuminates directly onto the crack.

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confidence: 99%

Detection of cracks in metal sheets using pulsed laser generated ultrasound and EMAT detection

et al. 2011

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“…Similar approaches have been thoroughly investigated in the doctoral theses presented in [121] and [122]. Additionally, the hybrid EMAT system was deployed in [123], overcoming the problem of detecting very low-amplitude diffracted waves through the illumination of the surface with a laser beam, produced from a high-energy pulsed laser. The laser source was used in order to generate ultrasonic waves of relatively great amplitude.…”

Section: Ultrasonicmentioning

confidence: 99%

Quality assessment in laser welding: a critical review

Stavridis

Papacharalampopoulos

Stavropoulos

2017

Int J Adv Manuf Technol

182

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Quality assessment methods and techniques for laser welding have been developed both in-and post-process. This paper summarizes and presents relevant studies being classified according to the technology implemented (vision, camera, acoustic emissions, ultrasonic testing (UT), eddy current technique (ECT)) for the quality inspection. Furthermore, the current review aims to map the existing modeling approaches used to correlating measured weld characteristics and defects with the process parameters. Research gaps and implications of the quality assessment in laser welding are also described, and a future outlook of the research in the particular field is provided.

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“…A variety of non-destructive testing (NDT) techniques are available in industries, such as radiographic testing (RT), magnetic particle testing (MPT), eddy current methods, magnetic flux leakage (MFL) and ultrasonic methods [1][2][3][4][5]. Due to its advantages of good penetration depth and mechanical flexibility, the piezoelectric ultrasonic method is widely used for thickness measurement, flaw evaluation and material characterization [6][7][8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

“…In this work, the test piece used is an aluminium plate, which is mainly affected by Lorentz force mechanism, so magnetostriction is not considered. The Lorentz force mechanism is: the coil induces eddy currents in the surface layers of the testing material, and the interaction between the static magnetic field and eddy currents produces a Lorentz stress based on Equation (1), which in turn generates ultrasound waves propagating within the testing sample. Considerable works were reported on the electromagnetic acoustic transducers (EMATs) simulation, which contained the electromagnetic model and the ultrasonic model [20][21][22][23].…”

Section: Introductionmentioning

confidence: 99%

Directivity analysis of meander-line-coil EMATs with a wholly analytical method

et al. 2017

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This paper presents the simulation and experimental study of the radiation pattern of a meander-line-coil EMAT. A wholly analytical method, which involves the coupling of two models: an analytical EM model and an analytical UT model, has been developed to build EMAT models and analyse the Rayleigh waves' beam directivity. For a specific sensor configuration, Lorentz forces are calculated using the EM analytical method, which is adapted from the classic Deeds and Dodd solution. The calculated Lorentz force density are imported to an analytical ultrasonic model as driven point sources, which produce the Rayleigh waves within a layered medium. The effect of the length of the meander-line-coil on the Rayleigh waves' beam directivity is analysed quantitatively and verified experimentally.

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A laser–EMAT system for ultrasonic weld inspection

Cited by 57 publications

References 7 publications

Detection of cracks in metal sheets using pulsed laser generated ultrasound and EMAT detection

Detection of cracks in metal sheets using pulsed laser generated ultrasound and EMAT detection

Quality assessment in laser welding: a critical review

Directivity analysis of meander-line-coil EMATs with a wholly analytical method

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