In this paper, a distant acoustic-laser NDE technique is proposed, utilizing a high powered standoff parametric
acoustic array (PAA) and laser Doppler vibrometry (LDV), for the detection of debonding and delamination
in multi-layer composite systems. Fiber-reinforced polymer wrapped concrete cylinder specimens with artificial
defect were manufactured and used in the validation of the technique. Low-frequency (50 Hz 2 kHz) and highfrequency
(2 kHz 7 kHz) focused sound waves were generated by PAA, and surface dynamic signatures of the specimens were remotely measured by LDV. From the results it is found that the proposed technique successfully
captures the presence of near-surface debonding/delamination.
This paper addresses a potential method to advance acoustic landmine detection by increasing operator and equipment standoff range from the minefield and developing a lightweight system that is potentially more practical than many currently researched systems. In this study, a parametric array acoustic source is evaluated to understand its potential for landmine detection. The array can transmit audible signals over 100 meters in air and has a weight of just four pounds. A proof-of-concept system was built at M.I.T. Lincoln Laboratory that uses a commercial parametric source to insonify the ground and excite buried mines. A commercial laser vibrometer was then used to measure the displacement velocity at the ground surface on and off the mine. This system has been demonstrated at an outdoor landmine facility and has measured signatures from buried anti-personnel mines. The overall concept shows promise; however, the parametric source used in this preliminary test was developed for home entertainment and will require substantial modification to be practical for landmine detection.