Improved inspection of Bonded Repairs

Bonded joints are used extensively for both civilian and military aircraft applications, especially for corrosion damage mitigation via patch bonding. Assessing the quality of these bonds is typically performed using NDE techniques such as bulk wave ultrasonics or thermography. These methods cannot reliably differentiate between a good bond and a so-called "kissing" bond. A kissing bond has no mechanical integrity existing between one or both of the substrates that sandwich the adhesive. Shear wave energy concentrated at the substrate-adhesive interfaces will certainly provide the necessary kissing bond detection capability. Bulk wave techniques could be designed to introduce shear waves into a bond structure but they would be impractical and tedious to implement. Guided waves, on the other hand, provide the resource to easily introduce shear waves into the bond interfaces. FBS, Inc. proposes the development of a guided wave technology that will be capable of determining the mechanical integrity and strength of bonded structures to solve the famous "kissing" bond problem. The guided wave technique, which has shown promise in previous work, will take advantage of recent advances in guided wave sensor technology and feature based detection algorithms to finally provide a solution to the "kissing" bond problem.