Investigations of passive wing technologies for load reduction

Abstract

Wings of modern aircraft have to be designed to give optimal response with respect to loads, comfort and performance. An essential part of the wing development is thus a design process which can take all these aspects into consideration. In the "Adaptive Wing" work package of the CleanSky "Smart Fixed Wing Aircraft" project, a multi-fidelity wing design method using aeroelastic tailoring has been developed. In the article, the process is presented in detail. The approach is based on a parametric wing design approach. Both beam models and shell models are derived and optimized in separate optimization environments. Investigations of the use of unbalanced laminates in aeroelastic tailoring are presented, employing the optimization of lamination parameters. The applications are demonstrated on two aircraft configurations, a long range and a short range transport aircraft. Further developments presented in the article include the introduction of CFD-based aerodynamics in the tailoring process, and a process extension to assess the influence of aeroelastic tailoring on fatigue.

Aeroelastic Wing Planform Design Optimization of a Flutter UAV Demonstrator

“…In the passive solutions, efforts are made to achieve directional wing stiffness in order to specifically influence wing properties such as load paths and vibration behavior. This can be realized with orthotropic materials as presented in [4]. It is shown, that with the additional design degrees, improved solutions for aircraft wings in terms of load elevation are possible.…”

Investigation of a Realistic Flap Modeling Using a Combination of Chimera Method and Grid Deformation on a Wing Fuselage Configuration

“…The passive gust load alleviation approach is based on a structural modification. For example, the aeroelastic wing behavior is adjusted by direction dependent stiffness properties of composite materials [5]. A disadvantage is mass increases due to stiffeners [6].…”

“…In order to reduce the resulting gust loads on the wing, having a positive effect on the structural mass and thus on the aircraft mass, two options exist for load reduction with regard to passive and active gust load reduction. Within the Smart Fixed Wing Aircraft (SFWA), different methods were investigated for the two gust load alleviation approaches [5]. The passive gust load alleviation approach is based on a structural modification.…”

Assessment of the efficiency of an active winglet concept for a long-range aircraft

“…However, these appealing solutions, some of whom are already flying on experimental aircraft like the FlexSys c system [6], present some major drawbacks such as the complexity, the maintenance and the certification of the actuation system [7]. Other technologies known as aeroelastic tailoring, use materials properties to optimised the wing for performances but also to provide passive loads alleviation capabilities [8].…”