Crack detection with gas-coupled laser acoustic detection technique. (7th June 2021)

• Record Type: Journal Article
• Authors: Vangi, Dario; Bruzzi, Mara; Caron, James Norbert; Gulino, Michelangelo-Santo
• Is Part Of: Measurement science & technology. Volume 32:Number 9(2021)
• Publication Date: 2021-06-07
• Subjects: non-contact ultrasonics -- air-coupled probe -- surface wave -- line inspection -- test configuration -- selectivity; Physical measurements -- Periodicals; Scientific apparatus and instruments -- Periodicals; Equipment and Supplies -- Periodicals; Science -- instrumentation -- Periodicals; Technology -- instrumentation -- Periodicals; Mesures physiques -- Périodiques; Physical measurements; Scientific apparatus and instruments; Periodicals; 502.87
• DOI: 10.1088/1361-6501/abfced
• Languages: English
• ISSNs: 0957-0233

Abstract

Abstract: Gas-coupled laser acoustic detection (GCLAD) is an unestablished ultrasonic detection technique based on the displacement that a laser beam sustains when intersected by an acoustic wave travelling in a fluid. In the present work, GCLAD for the noncontact detection of ultrasound is applied to identify surface defects on metal plates. Two GCLAD configurations are analysed, each associated with different sensitivities to cracks; specifically, GCLAD exhibits the highest sensitivity when inclined perpendicularly to the ultrasonic propagation direction in the air. The high angular selectivity allows evidencing only specific waves, those directly travelling in the component or reflected by defects. A higher ultrasonic amplitude is highlighted for GCLAD compared to air-coupled probes. The work ultimately demonstrates GCLAD's major advantage: the possibility of instantly performing an inspection over an entire line, rather than on a point as for traditional transducers.