On the use of adaptive internal structures for wing shape control

This paper describes part of a research programme investigating the development of "adaptive internal structures" concepts to enable active aeroelastic control of aerospace structures. A number of different concepts have been considered as part of the EU funded Active Aeroelastic Aircraft Structures (3AS) project that allow the bending and torsional stiffness of aircraft wings to be controlled through changes in the internal aircraft structure. The aeroelastic behaviour, in particular static bending and twist deflections, can be controlled through changes in the position, orientation and stiffness of the spars. In this paper, finite element models are used to explore the use of rotating spars to vary structural stiffness, thus adjusting the static aeroelastic wing twist and bending shape, and thus altering the lift and drag properties. The effect on the flutter characteristics is also explored. A number of experimental studies of the concepts are also described.