Optimizing the Performance and Affordability of Advanced Hybrid Structures (AHS)

This paper may be considered for a Keynote Introduction on the three planned sessions covering:  1) FML materials, microstructures, and properties, 2) design and analytical methods, and 3) ASIP, building blocks, and applications.

Air Force Research Laboratory, Air Vehicles Directorate envisions application of advanced hybrid materials to replace problematic monolithic metal in the current veteran aircraft fleet, but also leverage advanced hybrid structures to not only maximize traditional military aircraft performance parameters, but also minimize life cycle costs. The current state-of-the-art Fiber Metal Laminate (FML) material systems have shown improved fatigue resistance, excellent impact resistance and damage tolerance, as well as resistance to corrosion and lightning strike. Currently, GLARE (GLAss REinforced aluminum) is utilized on large acreage of the upper fuselage and leading edges of the horizontal and vertical tail of the A380 commercial aircraft.  Application of GLARE, or CentrAl (Center reinforced Aluminum) as replacement parts for veteran military aircraft enhances sustainment by reducing the frequency of inspection and increasing useful structural life.  Designs that reduce life-cycle costs and minimize structural weight are desirable for future military aircraft.

This paper will address the optimal performance and affordability of advanced hybrid structures.  Consideration of hybrid material properties will include a basic comparison to monolithic aluminum metal (elastic modulus and corresponding density), but also will investigate the performance of structural properties essential for part replacement.  Design of a replacement structure will meet form/fit/function, but also take advantage of higher dynamic stress levels due to the slow crack growth characteristic of the material and provide trade space opportunities between performance and sustainment.  The complexities involved in the design of such aircraft structures will require formal design optimization, likely crossing preliminary and detailed design.  Lastly, the advanced hybrid structure must address all technology challenges for the disciplined transition to a flight structure, managing risk and providing a life cycle cost benefit to the end-user.  As an overview on these topics, this paper will provide an introduction to these sessions of the Aeromat conference, specifically calling out other Keynote presenter accomplishments in each session topic area.