The main objective of the Advanced Aluminum Aerostructure Initiative (A3I) is to demonstrate the capability to achieve significant cost reduction in aerospace components through an integrated team of the material producer and OEM. Alcoa and Lockheed Martin Aerospace are teamed in A3I to optimize incumbent designs of the Lockheed Martin C-130 Hercules tactical airlifter. After a comprehensive part selection process, several parts were screened and one chosen based on cost savings potential and technology advancement. A wing bulkhead was evaluated for new manufacturing and assembly techniques through raw material selection, single piece machining, and friction stir welding (FSW).

Trade studies indicated that a design utilizing lap friction stir welding offered the great cost reduction opportunities. A lap FSW design was developed, but crevice corrosion was identified as a major risk for this design. In order to implement a FSW design on the plane in a timely manner, a lower risk butt FSW design was also developed and tested. This presentation will focus on the design evolution of the bulkhead, and the results of the testing programs for both the lap and butt FSW designs.