Abstract
Critical issues are examined in the application of laser generation and detection of ultrasound to the inspection of large area air-frame composites. Among these issues are surface roughness, signal-to-noise ratio, insensitivity to the path length between the part and detector, and wide band vs. narrow-band generation. Demonstrated is the feasibility of transmission C-scans of 150 ply Gr/epoxy panels containing simulated delaminations. Waveforms having a signal-to-noise ratio of greater than 40 dB in 15-mm thick Gr/epoxy were obtained with generating laser powers well below the ablation limit for the graphite epoxy. Detection was shot-noise limited with a detector noise figure of about 5–10 dB.
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Tittmann, B.R., Linebarger, R.S. & Addison, R.C. Laser-based ultrasonics on Gr/epoxy composite. J Nondestruct Eval 9, 229–238 (1990). https://doi.org/10.1007/BF00565641
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DOI: https://doi.org/10.1007/BF00565641