Field Level Repair/Joining of Composite Aircraft Structure Using Ultrasonic Methods

Foster-Miller is proposing a unique repair/joining method that eliminates fasteners, does not require autoclave or oven cure, and is equally compatible with field and shop floor operations. The proposed process utilizes ultrasonic energy for two discrete operations: 1) in-situ deposition of a thermoplastic composite laminate patch/splice and, 2) insertion of through thickness pins around the periphery of the patch/splice to react peel stress concentrations and increase bondline strength. Because the lamination and fiber insertion processes would use the same commercially available ultrasonic power supply, both processes could be combined into a single hand held or gantry mounted tool incorporating interchangeable ultrasonic and effectors. The approach offers many potential cost savings via low initial equipment costs, and reduction in labor time associated with preheating, repair site preparation and patch lay-up. The Phase I program will focus on the repair and joining requirements of real world military and commercial composite aircraft structures. Northrop Grumman (Vought) believes the proposed technology enables both repair and joining of advanced smart skin concepts involving leading edge embedded antenna arrays. Boeing Commercial Aircraft Group (BCAG) is primarily interested in applying the UTL/UAZ process to field repair of primary and secondary composite commercial aircraft structure.