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 opportunities to increase the integrity and performance of metal to composite joints. Specifically this effort will investigate CoMeld and Cold Spray technologies for their application to hybrid joining concepts. This program will focus on these new technologies for formation of in-situ fasteners for joining composites and metals. Initially coupon level tests will be performed using a design of experiments and the results will be used to populate the analysis database. In addition, preliminary fatigue and corrosion performance questions for these new joints will be answered. The data will be used for down-selecting the “best” joining technique, which will subsequently be verified through subcomponent testing. The results will be used to conduct a cost benefit analysis to help implementation into LM-Aero applications. Successful completion of this program will result in the development of new joining methods that can be used by the various DoD contractors on numerous next generation aircraft.