PSI - Issue 16

Zinoviy Nazarchuk et al. / Procedia Structural Integrity 16 (2019) 11–18 Zinoviy Nazarchuk, Leonid Muravsky, Dozyslav Kuryliak / Structural Integrity Procedia 00 (2019) 000 – 000

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Fig. 5. Timing sequence of n th pair of SPs recorded with equal light exposure of K accumulated elementary SPs using an optical shutter.

a

b

(i) Detection of four inner holes with a diameter of 4 mm, f =85 kHz.

(ii) Detection of inner hole with a diameter of 12 mm, f =30 kHz.

Fig. 6. (a) functional diagram of the ODS breadboard: laser (1), beam expander (2), mirror (3), multilayer composite (4), digital camera (5), computer (6), US transducer (7), clock and control unit (8); (b) resultant speckle patterns that detect blind circular holes located at a depth of 1 mm under the observed surface of a fiberglass panel: (i) four inner holes with a diameter of 4 mm detected at the resonant frequency 85 kHz; (ii) inner hole with a diameter of 12 mm detected at resonant frequency 30 kHz (this speckle pattern has undergone to digital image preprocessing ).

References

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