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

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 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

This paper presents a design tool based on computational methods for the aerostructural analysis and optimization of aircraft layouts at the conceptual design stage. The whole methodology is based upon the integration of geometry construction and aerodynamic and structural analysis codes that combine depictive, computational, analytical, and semiempirical methods validated in an aircraft design environment. The main module for structural sizing and numerical aeroelastic analysis, named NeoCASS (next-generation conceptual aerostructural sizing suite), is presented here. The numerical kernel handling the aerostructural interaction enables the creation of efficient low-order high-fidelity models that are particularly suitable within a multidisciplinary design optimization framework to drive the optimization tool in the most appropriate direction. This makes it possible to address adverse aeroelastic issues, such as divergence, control surface reversal, flutter, and increased drag at cruise speed due to structural deformation. All of these issues generally lead to considerable changes in the structural design, which in turn might pose limitations on the flight envelope or weight penalties. The late discovery of these types of issues may result in significant cost increases and, in some cases, it may lead to the termination of the project. To overcome and remove these issues, the influence of structural deformation on flight and handling performances, of weight, and of design costs needs to be taken into account as early as possible in the design process