Portable Additive Friction Stir Repair of Aircraft Fastener Holes

Navy aircraft wing skins can develop corrosion at fastener holes, which needs to be repaired at depots to eliminate crack initiation and fatigue crack growth. The current Navy approach consists of drilling out the holes past the deepest corrosion indication and inserting a bushing. This is a slow, tedious process that weakens the wing skin locally (bigger hole) and does not result in a metallurgical bond. We have adapted a conventional solid-state welding process currently used for large-scale manufacturing (conventional friction stir welding) and miniaturized the technology to facilitate the repair of holes. Our Additive Friction Stir Bushing (AFSB) technology is portable, making it ideally suited to Navy (and other) on-aircraft hole repair applications. During the Phase I project, we will assemble the AFSB, complete repair testing on relevant materials, and design the prototype for aircraft repair. During Phase II, we will complete the system design, fabrication, and testing and transition the technology to the Navy fleet.