Multi-Functionality in Metallic Airframe Structures

Aerospace structures must meet a multitude of requirements, including withstanding mechanical loading, resisting lightning strike, minimizing drag, and supporting aircraft systems.  Metallic aerostructures are already intrinsically multi-functional, meeting for example both complex stress cases and lightning strike requirements.  However, there are many other functions that currently necessitate the addition of weight to the overall airframe which could be addressed by better integration of the wider requirements into the design of the original material.   

 Alcan Global Aerospace is addressing this issue with the aim of providing innovative multi-functional solutions that retain the robustness and improve the cost-efficiency of aluminium aerostructures.  Developing such solutions requires not only deep understanding of OEM requirements, but also innovative thinking on additional functionality.  Local property tailoring, for example, can be used to optimize the performance of a large-scale metallic part with respect to detailed loading and other requirements.  However, a similar approach can be used to address additional functions: for example, local sub-stiffening in integral parts could be used not only to optimise the damage tolerance/compression stability of a component but also to tailor its aero-elastic response.   Similarly, structural health monitoring (SHM) enabling features can be integrated into aluminium semi-products during materials processing, and thus provide opportunities for damage or stress measurement without generating additional complexity for handling or subsequent maintenance.  Other opportunities include possibilities of surface texturing to reduce drag, and alloys/designs more suited to tomorrow’s hybrid structures.

 An update of Alcan’s progress in these fields will be presented, as well as a discussion of the opportunities and issues associated with their exploitation in a real aerostructure.