CORDIS

"The proposal aims to extend the capabilities of a composite laminate design tool D2B (Designed to Build) to demonstrate a flexible load carrying structural skin for morphing wings. A unique composite skin construction that will allow the skin stiffnesses to vary spatially so as to provide the most flexible skin that can be morphed with minimum energy requirements, while aerodynamic load carrying capability is maintained. The software tool will be used to produce laminate designs that fully take into account coupled bending and in-plane stiffnesses so that both load paths to achieve proper load transmission from the points of actuation loads on the skin to the fixed points, while the coupled tailored bending stiffness distribution will ensure achieving prescribed deformations. The desired stiffness distribution will be achieved by spatially varying the fibre orientation of the individual layers of the laminate by adopting a steered fibre construction, and by selectively terminating certain layers of the laminate to create a blended laminate thickness variation.

The integrated tools will be used in an optimisation formulation with the objective of achieving a user defined deformed shape with constraints on strength, stiffness, fabrication limitations, actuation forces, while accounting for large deformations and aerodynamic loads. The optimisation formulation will also be able to calculate the energy requirement to achieve the deformed shape. The optimal fibre path distribution of the individual layers will be designed in a two-step design formulation. The first step will produce theoretically optimal stiffness distribution of the skin in terms of stiffness matrices, while satisfying strength and a limited number of manufacturing constraints. In the second step, fibre paths of the individual layers will be computed so as to achieve theoretically optimised stiffness distribution. The optimal design will be fabricated using a state of the art fibre-placement machine."