Multiagent Control of Airplane Wing Stability with “Feathers” under the Flexural Torsional Flutter

This paper proposes a novel method for the unbounded oscillation prevention of an aircraft wing under the flexural torsional flutter, an innovative multiagent attitude to control an aircraft wing with a surface consisting of managed rotating “feathers” (agents). Theoretical evaluation of the method demonstrates its high aptitude to avoid an aircraft wing’s flexural-torsional vibrations via expansion of the model’s ability to dampen the wing oscillations. It potentially allows increasing an aircraft’s speed without misgiving of the flutter. A new way to control an aircraft wing based on the Speed-Gradient methodology is suggested to increase the maximal possible flight speed without a flutter occurrence. Provided experiments demonstrate the theoretical advantage of the multiagent approach to the “feathers” rotation control.

Improvement of the Mechanical Characteristics of Fiber Metal Laminate (FMLs) Used for Aircraft Wing Using Epoxy-Resole

The Fiber Metal Laminates (FMLs) was studied and improved the mechanical properties were used for aircraft wing. The FMLs are consisting of metal sheets reinforced with fiber bonded by matrix phase. The FMLs consist of seven layers to produce the Hybrid composite materials that made from 2024-T3 Aluminuim sheets with carbon and glass fibers as reinforcement and bonded using adhesion materials that are locally manufactured from resole resin with adding using epoxy resin. By using the FMLs, the mechanical characteristics have been improved and the weight of the aircraft wing has been reduced. The mechanical characteristics have been improved comparing to other FMLs using commercial epoxy. The FMLs with carbon and glass fibers have high tensile strength and elastic modulus but low yield and elongation comparing with the FMLs of carbon fibers as a reinforcement. The flexural modulus and impact toughness is high for the FMLs with glass fiber comparing with jute fibers with adding using carbon fiber as areinforcement.The Aramid Reinforced Aluminum Laminates (ARALLs) have low fatigue strength than FMLs using carbon fiber as reinforcement. The FMLs are lower ratio of ultimate to yield strength and density than 2024-T3 Aluminum alloy that commonly used in aircraft wing.

Effect of Cut-Out Shape on the Stresses in Aircraft Wing Ribs under Aerodynamic Load

Ribs in aircraft wings maintain the airfoil shape of the wing under aerodynamic loads and also support the resulting bending and shear loads that act on the wing. Aircrafts are designed for least weight and hence the wings are made of hollow torsion box and the ribs are designed with cut-outs to reduce the weight of the aircraft structure. These cut-outs on the ribs will lead to higher stresses and stress concentration that can lead to failure of the aircraft structures. The stresses depend on the shape of the cut-outs in the ribs and thus in the present work, the commercial software ANSYS was used to evaluate the stresses on the ribs with different shapes of cut-outs. Four different shapes of cut-out were considered to study the effect of cut-out shape on the stresses in the ribs. It was found that the best shape for the cut-outs on the ribs of wings to reduce weight is elliptical.

Kernel Principal Component Analysis for Structural Health Monitoring and Damage Detection of an Engineering Structure Under Operational Loading Variations

This paper highlights kernel principal component analysis (KPCA) in distinguishing damage-sensitive features from the effects of liquid loading on frequency response. A vibration test is performed on an aircraft wing box incorporated with a liquid tank that undergoes various tank loading. Such experiment is established as a preliminary study of an aircraft wing that undergoes operational load change in a fuel tank. The operational loading effects in a mechanical system can lead to a false alarm as loading and damage effects produce a similar reduction in the vibration response. This study proposes a non-nonlinear transformation to separate loading effects from damage-sensitive features. Based on a baseline data set built from a healthy structure that undergoes systematic tank loading, the Gaussian parameter is measured based on the distance of the baseline data set to various damage states. As a result, both loading and damage features expand and are distinguished better. For novelty damage detection, Mahalanobis square distance (MSD) and Monte Carlo-based threshold are applied. The main contribution of this project is the nonlinear PCA projection to understand the dynamic behavior of the wing box under damage and loading influences and to differentiate both effects that arise from the tank loading and damage severities.