The great interest in developing morphing airfoils is mainly based on their capability to adapt their shape to optimize some specific aircraft performance indices during the mission. Nevertheless, the design of these kinds of devices requires the availability of ad hoc-developed procedures able to tackle the conflicting requirements such as the high deformability requested to change the airfoil shape coupled to the load-carrying capability and to the low weight. The article proposes an approach for optimal airfoil-morphing design based on a compactapproach to describe the airfoil geometry coupled to a two-level optimization procedure. In the first one, the best deformed airfoil configuration is determined as the most efficient aerodynamic shape which at the same time limits the requested energy to deform the airfoil skin. In the second optimization level, the best internal structural configuration is obtained using an ad hoc-developed topology optimization tool based on genetic algorithms that synthesize a compliant structure able to adapt itself in order to match the optimal shape coming out from the first level. The procedure has been applied to design the morphing leading and trailing edges for an NACA 63_2215 airfoil.

Purpose – The purpose of this paper is to provide an overview of the design and experimental work of compliant wing and wingtip morphing devices conducted within the EU FP7 project NOVEMOR and to demonstrate that the optimization tools developed can be used to synthesize compliant morphing devices. Design/methodology/approach – The compliant morphing devices were “designed-through-optimization”, with the optimization algorithms including Simplex optimization for composite compliant skin design, aerodynamic shape optimization able to take into account the structural behaviour of the morphing skin, continuum-based and load path representation topology optimization methods and multi-objective optimization coupled with genetic algorithm for compliant internal substructure design. Low-speed subsonic wind tunnel testing was performed as an effective means of demonstrating proof-of-concept. Findings – It was found that the optimization tools could be successfully implemented in the manufacture and testing stage....

This paper describes the activities performed at Politecnico di Milano within the FP7–NOVEMOR Project framework for the design, manufacturing, and wind tunnel test of a wing model equipped with morphing leading and trailing edges based on compliant structures. Starting from the reference aircraft, that is, a typical regional aircraft developed during the NOVEMOR project, a small-scale wind tunnel wing model is developed to validate the proposed morphing concept and to correlate the numerical models in an experimental environment. Special attention is devoted to the selection of the manufacturing technology due to the difficulty in realizing compliant structures with sufficient accuracy at a small-scale level. After a brief summary of the tools developed for the design of variable camber morphing wings, the paper describes in detail the design and manufacturing phases along with the functionality and wind tunnel tests. The results are used to validate the procedure adopted for the synthesis of the compliant structures and to evaluate the aerodynamic performances of the morphing wing.

This paper presents the work that has been performed on a wind-tunnel aeroelastic wing model to implement a multisurface modal control system. Wing model realization, the control system, and experimental setup were described briefly here, together with a methodology used to numerically tune the simple control system. Usage of a multiple wind-tunnel test session has been adopted first to perform numerical–experimental correlations and then to optimize control parameters. The entire control system demonstrates the capability to damp the wing bending and torsion modes while still remaining stable within the flight envelope

A design procedure for the synthesis of active camber morphing wing devices is proposed. A topology optimization initially defines the internal structure that is further enhanced by structural size and shape optimizations, and these optimizations are based on the distributed compliance concept. The size optimization enables the adaption of the topology solution to other materials and geometries while refining the topology solution to improve the shape quality of the skin deformation. Then, the structural shape optimization enables the reduction of the stress peaks inside the compliant structure and the finalization of the details to obtain a solution that is closer to the manufacturing process stage. The proposed methodology is used in the design of an adaptive droop nose to be installed on a reference regional aircraft, and two different design applications are considered. The first application is the validation of the procedure at the full–scale level using a superelastic material for the internal structure. The second application is the design of a corresponding 3D–printed prototype, in which both geometry and material changes are considered, for experimental validation. The results show satisfactory shape quality and the achievement of structural feasibility. The experimental functional test of the scaled prototype demonstrates the effectiveness of the adopted morphing solution.

This paper describes the development of a new state-of-the-art large wind tunnel model for active flutter suppression studies as well as the supporting techniques used in tests focused on the effects of uncertainty. Design guidelines and the resulting aeroelastic characteristics of the model are covered together with representative test results. Those would allow other researchers working in this area to develop control laws for the new model and evaluate them. A number of important lessons and insight are reported regarding the design of the model, the level of success of commonly used mathematical modeling techniques to capture its behavior, sources of analysis/test correlation discrepancies, multifunction utilization of control surfaces for both system identification and flutter suppression, active flutter suppression testing safety, and techniques for estimating the robustness of closed-loop active aeroservoelastic systems by tests. The new system has made it possible to repeatedly push the actively controlled model, using various flutter suppression control laws (safely), to the actual flutter limit in tests numerous times. This capability is just one of the new experimental capabilities that the new system brings to the aeroelastic active control community.