Morphing Devices for a Wing and Wingtip Based on Compliant Structures

This paper presents work being conducted by the German Aerospace Center (DLR) and the Politecnico di Milano (POLIMI) on morphing structures as part of the EU FP7 NOVEMOR Project. A regional jetliner was the reference aircraft and a droop-nose morphing wingtip (DLR) and various leading and trailing edge devices on the wing (POLIMI) were applied to this reference aircraft. Various design and optimization tools were developed and explored by both institutions. For the DLR wingtip, a design chain was employed whereby a composite skin optimization tool was first used to define the layup sequence and geometry for the skin followed by topology optimization for the design of the internal compliant structure. Construction is underway of a full-scale wind tunnel model and the results of the ground testing of a demonstrator show the working principle of the design chain and its compliant components. For the morphing devices of POLIMI, the definition of the optimal morphing shapes, taking into account both aerodynamic performances and skin structural constraints, was performed before, using the code PHORMA. Then the code SPHERA was used to design the compliant mechanism able to meet the optimal shapes previously defined. Both codes are part of a parametric framework incorporating CFD-FEA interaction and genetic algorithm based optimizers. Manufacturing of prototypes for wind tunnel testing is also in progress and the experimental setup is also presented in this paper.