Guided Wave/Fiber Optic NDE of Distributed Adhesive Bonds

Adhesive bonds are a critical joining logy for modern aircraft, and health monitoring of distributed bond areas is an important part of airframe preventative and conditioned based maintenance programs. The introduction of smart composite materials with embedded fiber optics (FO) makes possible the union of two sciences into a leap-ahead bond nondestructive evaluation (NDE) technology - ultrasonics and optics. Ultrasonic guided waves (GW) are one of the most defect sensitive NDE methods known, and they can probe at large (over 20ft in composites) from the inspected area. By using embedded fiber optics as receivers the acoustic guided wave passage is sensed internal to the part under inspection. This provides an NDE capability heretofore unavailable¿monitoring guided wave structure at different points within the part to determine distributed bond health. A ground based maintenance system, GW/FO NDE would add less than 5 pounds to aircraft weight. The inspection would be done by connecting a knee high instrument rack to the aircraft using singlemode FO connectors. Inspection times should be on the order of 10-15 minutes for fighter size aircraft with 5-6 GW/FO embedded arrays. A commercialization approach for GW/FO NDE is presented for both military and airline industries, and company resources and university M.B.A. programs are used to assess market potential for this innovative NDE product.