Identification of Internal Planar Square Defects in Composite Panels Using Optoacoustic Technique

A new approach for determining the size and depth of internal square planar defects in laminated composite panels using a developed optoacoustic technique is proposed. The size of the defect is determined by spatial light responses generated by a region of interest, which is located above the defect and oscillated at the fundamental frequency or multiple resonant frequencies. The defect depth is determined using the family of experimental dependencies of the resonant frequency on the defect size. Experimental results proved the effectiveness of the proposed approach in identifying internal planar square defects in fiberglass panels.