Future Aircraft Structures: From Metal to Composite Structures

In the twentieth century mobility became an important part of life. Aircraft and cars changed from invented necessities into necessary inventions and after more than 70 years of growth the conventional solutions are reaching the point of saturation. Since the 1950s aircraft efficiency improvements were mainly based on refinements in aerodynamics (15%) and propulsion (40%). Structures on the other hand (concepts, materials and manufacturing techniques) did not change all that much, and relative weight reductions were annulled by comfort, safety and more systems. Even the latest developments in tools for analysis and design did not result in structure weight reduction, which might be an indication that a leap to novel materials and manufacturing techniques, a leap to new technologies, is the only way to achieve the necessary improvements. In this article composite materials are presented as a solution to not only reduce structural weight, to a maximum of 12% operational empty weight, but also to reduce exploitation costs and emissions for a 30-year life span. Although fibre-reinforced polymers are more expensive per kilogram than most metals, on a lifetime basis operational cost can be reduced by a decrease in fuel consumption, maintenance and inspection costs and, last but not least, manufacturing cost. Therefore, an integral approach for structure development is discussed, from concepts and materials to downstream manufacturing techniques. The emphasis is on structure and material simplicity and, very challenging, on the reduction of the number of production steps from suppliers to final construction.