Extremely deformable morphing leading edge: Optimization, design and structural testing

The future generation of high-lift devices needs to be improved to reduce the noise footprint and increase the performance for takeoff and landing of transport aircraft. To contribute to these goals, an active blown Coandă flap-based high-lift system is being investigated within the German national Collaborative Research Center 880 as an alternative to the state-of-the-art flaps. A key part of this system is an adaptive gapless droop nose with extremely large morphing deformation. The design and construction of this component are based on a structural optimization framework. The framework consists of two hierarchical design steps: an optimization of the hybrid composite skin layout with integral T-stringers, acting as joints to the inner actuation mechanism, and the kinematic optimization of the latter. A hybrid skin structure allows a large curvature to rupture in the morphing direction, while providing high stiffness in the transverse direction. This article describes a full-scale hybrid composite morphing droop nose and its structural tests. The results of these tests are finally compared to the finite element simulation and applied for validation of the optimization framework. A sensitivity analysis is provided to evaluate the influence of modelling and manufacturing uncertainties to the shape quality.