Laser-ultrasonic inspection of surface-breaking tight cracks in metals using SAFT processing

Lévesque, Daniel; Ochiai, Makoto; Blouin, Alain; Talbot, Richard; Fukumoto, Atsushi; Monchalin, Jean‐Pierre

doi:10.1109/ultsym.2002.1193508

Cited by 9 publications

(9 citation statements)

References 6 publications

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“…The detection of a 0.3 mm deep LOP in a similar specimen was also observed. However, the quantitative estimation of the depth appears difficult, a situation similar to that found in a previous work for crack detection [6].…”

Section: Inspection Of Butt Jointssupporting

confidence: 64%

Residual Stress Measurement in Friction Stir Welds Using Laser Ultrasonics

Lévesque¹,

Dubourg²,

Lord³

et al. 2009

AIP Conference Proceedings

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The laser-ultrasonic technique is proposed for defect detection and residual stress measurement in friction stir welds (FSW). When combined with the synthetic aperture focusing technique (F-SAFT), very good performances are achieved for detecting lack of penetration in butt joints, the detection limit coinciding with the conditions of reduced mechanical properties. Also, the detection of kissing bonds seems to be possible in lap joints with frequencies up to 200 MHz. Another application is the measurement of residual stresses induced by the FSW process. The method is based on monitoring the velocity change of the laser generated surface skimming longitudinal wave, propagating just below the surface and being found much more sensitive to stress. The residual stress profile measured across the weld line is in good agreement with results from a finite element model and from strain gauge measurements.

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Section: Inspection Of Butt Jointssupporting

confidence: 64%

Residual Stress Measurement in Friction Stir Welds Using Laser Ultrasonics

Lévesque¹,

Dubourg²,

Lord³

et al. 2009

AIP Conference Proceedings

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“…Ultrasonic-based systems use high-frequency sound waves to detect pipe properties such as thickness, shape, and presence/sizes of defects [31]. Laser-based and ultrasonic-based methods can be combined to obtain higher quality data [32].…”

Section: ) Manual and Semiautonomous Methodsmentioning

confidence: 99%

On Optimizing Autonomous Pipeline Inspection

Lin

et al. 2012

IEEE Trans. Robot.

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Abstract-This paper studies the optimal inspection of autonomous robots in a complex pipeline system. We solve a 3-D region-guarding problem to suggest the necessary inspection spots. The proposed hierarchical integer linear programming optimization algorithm seeks the fewest spots necessary to cover the entire given 3-D region. Unlike most existing pipeline inspection systems that focus on designing mobility and control of the explore robots, this paper focuses on global planning of the thorough and automatic inspection of a complex environment. We demonstrate the efficacy of the computation framework using a simulated environment, where scanned pipelines and existing leaks, clogs, and deformation can be thoroughly detected by an autonomous prototype robot.

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“…In the conventional ultrasonic method, an improvement of the lateral resolution and signal-to-noise ratio is achieved by focusing the acoustic field with lenses or curved transducers or by using a computational technique that basically consists of performing the focusing numerically. Originally developed in the time domain, SAFT (Synthetic Aperture Focusing Technique) can be beneficially implemented in the frequency domain (F-SAFT) [10][11][12]. F-SAFT is based instead on the plane wave decomposition of the measured ultrasonic field at the surface (angular spectrum approach) and then utilizes a back propagation algorithm to find the field in any plane inside the material.…”

Section: The F-saft Proceduresmentioning

confidence: 99%

A New Diagnosing Method of the Internal Structure of the Titanium Fan of a Jet Engine with Laser Ultrasonics

Swornowski¹

2011

Metrology and Measurement Systems

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Advanced metallic material processes (titanium) are used or developed for the production of heavily loaded flying components (in fan blade construction). The article presents one process for diagnosing the blade interior by means of laser ultrasonography. The inspection of these parts, which are mainly made of titanium, requires the determination of the percentage of bonded grain sizes from around 10 to 30 m. This is primarily due to the advantages of a high signal-to-noise ratio and good detection sensitivity. The results of the research into the internal blade structure are attached.

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Laser-ultrasonic inspection of surface-breaking tight cracks in metals using SAFT processing

Cited by 9 publications

References 6 publications

Residual Stress Measurement in Friction Stir Welds Using Laser Ultrasonics

Residual Stress Measurement in Friction Stir Welds Using Laser Ultrasonics

On Optimizing Autonomous Pipeline Inspection

A New Diagnosing Method of the Internal Structure of the Titanium Fan of a Jet Engine with Laser Ultrasonics

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