R. J. Bucci, M. Kulak, M. B. Heinimann, M. A. James, W. H. Grassel, R. L. Brazill, Alcoa, Inc., Alcoa Center, PA; P. A. Hooijmeijer, GTM Advanced Structures, 2497 GB The Hague, Netherlands
This presentation summarizes findings derived from a 3 year Alcoa testing program conducted using large stiffened panels to evolve and validate new metallic intensive designs capable of dramatic structural weight and cost savings over today’s commercial transport aircraft standards. Damage tolerance performance of tension-dominated lower wing and fuselage crown and side cover panels was measured against crack growth and residual strength (two-bay crack scenario) requirements sizing the majority acreage of tension-dominated wing and fuselage structure. The structural concepts evaluated contained advanced alloys, novel design, and innovative manufacturing methods. The built-up and integrally stiffened panels tested combined various elements of advanced alloys (including aluminum-lithium alloys), fibers for selective reinforcement or in a new hybrid material configuration, and advanced weld-joining methods. Both fiber reinforced and non-reinforced test panel variants were considered to gauge the benefit of fiber placement options. Testing confirmed the tailoring potential of combining advanced aluminum alloys with fibrous material forms (the latter either as a fiber-metal laminate reinforcing strap or new hybrid material configuration) to achieve substantial opportunity for improvements in structural performance and cost. Tests conducted at operating stress levels higher than current industry standards showed that the fiber reinforced metallic and hybrid variants have potential for weight and cost savings (both acquisition and operational) that far surpass that of today's mono-material construction. The testing also demonstrates this technology's enormous potential for driving down aircraft inspection/maintenance burden. Finally, understanding derived from post-mortem inspection and teardown of tested panels is reviewed to support the technology transition and concept of "care-free" structure.
Summary: This presentation summarizes findings derived from a 3 year Alcoa testing program conducted using large stiffened panels to evolve and validate new metallic intensive designs capable of dramatic structural weight and cost savings over today’s commercial transport aircraft standards.
