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.

This paper deals with the weight estimation of the wing box of a commercial aircraft by means of a procedure suitable for very large liners and/or unconventional configurations for which statistical data and empirical formulas may not be sufficiently reliable. Attention is focused on the need to account for aeroelastic interaction from a very preliminary stage of the design cycle. The procedure exploits the first of three levels of a multilevel structural optimization system conceived for the preliminary design of the wing primary structure and a simplified evaluation of the cross-sectional properties. The comparison between weight estimates obtained with the present procedure and predictions supplied by available literature shows a satisfactory agreement

No abstract

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. Preliminary insight into the performance of the compliant structure has been made during the first wind tunnel tests. Practical implications The tools in this work further the development of morphing structures, which when implemented in aircraft have potential implications to environmentally friendlier aircrafts. Originality/value The key innovations in this paper include the development of a composite skin optimization tool for the design of highly 3D morphing wings and its ensuing manufacture process; the development of a continuum-based topology optimization tool for shape control design of compliant mechanisms considering the stiffness and displacement functions; the use of a superelastic material for the compliant mechanism; and wind tunnel validation of morphing wing devices based on compliant structure technology.

An optimization procedure for the shape design of morphing aircraft is presented. The process is coupled with a knowledge-based framework combining parametric geometry representation, multidisciplinary modelling, and genetic algorithm. The parameterization method exploits the implicit properties of the Bernstein polynomial least squares fitting to allow both local and global shape control. The framework is able to introduce morphing shape changes in a feasible way, taking into account the presence of structural parts, such as the wing-box, the physical behaviour of the morphing skins, and the effects that these modifications have on the aerodynamic performances. It inherits CAD capabilities of generating 3D deformed morphing shapes and it is able to automatically produce aerodynamic and structural models linked to the same parametric geometry. Dedicated crossover and mutation strategies are used to allow the parametric framework to be efficiently incorporated into the genetic algorithm. This procedure is applied to the shape design of Reference Aircraft (RA) and to the assessment of the potential benefits that morphing devices can bring in terms of aircraft performances. It is adopted for the design of a variable camber morphing wing to investigate the effect of conformal leading and trailing edge control surfaces. Results concerning four different morphing configurations are reported.