Damage inspection of fiber reinforced polymer-concrete systems using a distant acoustic-laser NDE technique

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.