An Advanced NDE Approach to Determine the Adhesive Bond Strength

Bonded composite materials offer considerable opportunity to reduce manufacturing cost, improve structural performance, and improve fuel efficiency of aircraft. However, bonded composite aircraft structures continue to be a challenge to manufacture due to the certification requirement to determine the strength of the bonds in the structures - before they are placed into service. Current testing techniques involve statically loading the structure to some specified load level to place the bond line under load. If the bond does not fail, it is determined to be acceptable and the structure is placed into service. This test method is costly and time consuming. The proposed solution provides a method to test the entire bond at a near uniform shear. If the bond is within specification, the technology would be non-destructive. However, if the bond were weaker than the specified value, the bond would fail. A single bond evaluation procedure will both proof load the bond and detect bond failures. The proposed technology tests the entire bond and not a few points along the bond joint as with laser bond inspection technology. The project would take the technology from inception (TRL 2) to a TRL of 7-8 at the end of the SBIR funding.