A Roadmap for the Metallic Airframe Structures of the Future

Materials’ choices for the next generation of aircraft will affect many of the parameters that govern value for airlines.  Fuel efficiency (through both structural weight, but also aerodynamic efficiency), manufacturing cost (including material but also component and final assembly costs) and non-fuel operational costs (e.g. maintenance) are all affected by the choice of materials and corresponding technologies.  Moreover, individual technology choices can also affect multiple value criteria: for example, choice of assembly technique affects not only manufacturing cost but also performance (through joint efficiency and subsequent surface roughness) and maintenance.

Currently, airframers’ consideration of metallic solutions largely relegates them to the status of today’s reference structures.  As such, these references correspond to technologies designed and frozen in the late 20^th century and selected with a different set of priorities.  Innovative thinking and corresponding low maturity research on criteria that have recently been more prominent - such as maintenance, high rate manufacturing, and function integration – are dominated by composite structures and often not transferable to metallic solutions.  A parallel effort needs to be made on developing technology bricks that address the full range of requirements, so that aluminium-based airframe solutions adequately address today’s key value criteria.

In this paper Constellium’s roadmap for aluminium-based technology development will be presented.  Three platforms are considered: fuselage, wing and internal structure.  For each of these platforms, a selection of technologies at relatively low maturity levels has been assessed.  Technology selection is made according to potential regarding fuel efficiency, manufacturing cost, and non-fuel operational costs.  A strategy for maturing these technologies to an appropriate technology readiness level in time for the next generation of commercial aircraft is proposed.