Innovative, Weight Efficient, Composite/Metallic Structural Joining Concepts

Currently aircraft composite and metal structures are joined by fastening them in place using riveted or bolted joints. Although fastened joints largely avoid concerns associated with thermally induced stresses and strains from CTE mismatches, such designs add weight, manufacturing complexity and cost to the design. Recent advances have given rise to new opportunities to increase the integrity and performance of metal to composite joints. This effort will investigate these new technologies for their application to hybrid joining concepts. This program will design, fabricate and test specimens from one technology, which benefits from newly developed metal processing capabilities. Two other technologies will also be analyzed to determine their merit and feasibility. Design optimization will be accomplished on all three concepts by first performing an analysis of the joints using the analytical tools developed under the Composites Affordability Initiative (CAI). Optimized joints representing the most promising technology will then be fabricated and mechanically tested to validate the new joining concept and model and to demonstrate and quantify their technical feasibility. Successful completion of this program will result in new joining methods that will be used by the various DoD contractors on potentially numerous new vehicles.