A Generic Morphing Wing Analysis and Design Framework (original) (raw)

2011, Journal of Intelligent Material Systems and Structures

A generic framework for morphing wing aeroelastic analysis and design is presented. The wing is discretised into an arbitrary number of wing segments. Two types of actuation mechanisms are identified: inter-rib mechanisms operating across a wing segment and intra-rib mechanisms acting between two adjacent wing segments. Virtually, any shape can be obtained by distributing four morphing modes over the entire morphing wing. Three are an intra-rib mechanism and one is an inter-rib mechanism. The intra-rib modes are wing shear, twist and extension, and the inter-rib mode is wing folding. The wing is modeled using a close coupling between a non-linear beam formulation and Weissinger aerodynamics. The framework is intended to aid quick preliminary design of morphing wings to trade-off contradictory requirements in a flight mission. The morphing wing can be optimized for discrete points in the flight mission, and for the entire flight mission. The framework can be used to predict aerodynam...

Energy-based aeroelastic analysis of a morphing wing

Modeling, Signal Processing, and Control for Smart Structures 2007, 2007

Aircraft are often confronted with distinct circumstances during different parts of their mission. Ideally the aircraft should fly optimally in terms of aerodynamic performance and other criteria in each one of these mission requirements. This requires in principle as many different aircraft configurations as there are flight conditions, so therefore a morphing aircraft would be the ideal solution. A morphing aircraft is a flying vehicle that i) changes its state substantially, ii) provides superior system capability and iii) uses a design that integrates innovative technologies. It is important for such aircraft that the gains due to the adaptability to the flight condition are not nullified by the energy consumption to carry out the morphing manoeuvre. Therefore an aeroelastic numerical tool that takes into account the morphing energy is needed to analyse the net gain of the morphing. The code couples three-dimensional beam finite elements model in a co-rotational framework to a lifting-line aerodynamic code. The morphing energy is calculated by summing actuation moments, applied at the beam nodes, multiplied by the required angular rotations of the beam elements. The code is validated with NASTRAN Aeroelasticity Module and found to be in agreement. Finally the applicability of the code is tested for a sweep morphing manoeuvre and it has been demonstrated that sweep morphing can improve the aerodynamic performance of an aircraft and that the inclusion of aeroelastic effects is important.

Design of a Morphing Wing : Modeling and Experiments

AIAA Atmospheric Flight Mechanics Conference and Exhibit, 2007

This paper details the design and modeling of a novel morphing wing developed at Texas A & M University. Twistable sections with an elastomeric skin characterize the wing as a distinct actuator in aerospace vehicles. Aerodynamic models of the wing were developed using Prandtl's Lifting Line Theory. 1 These models were validated using wind tunnel tests conducted at the low speed wind tunnel at Texas A& M University. It was found that the operating envelope of the angle of attack of the wing was enhanced by the twistable sections.

Aeroelastic Modeling of Morphing Aircraft Wings

2014

An analytical aeroelastic model to investigate the aeroelastic stability of a span morphing aircraft is derived. Structural and aeroelastic models are derived with the parameteric variations introduced by a span morphing wing. Dynamic aeroelastic stability analysis is performed with thin airfoil theory and CFD. A CFD analysis of span morphing shows the lift increases in a non-linear fashion during the morphing process, and after the morphing is completed. The utter analysis, based on the CFD results, shows a signicant reduction in utter velocity during morphing due to inertial, elastic and aerodynamic variations, and due to the ow evolution after the morphing period. This study shows that the development of low delity aeroelastic models of morphing wings, supplemented with high delity analysis, can quantify the phenomena associated with the morphing and also serve as precursor to a computationally expensive, fully coupled high delity simulation of utter due to morphing.

Enabling Technologies and Aerodynamics Implications of a Morphing Wing

The concept of morphing wing is currently new to aviation industries. This concept was inspired by the bird flight. Being able to successfully develop this technology, aircraft can be able to adjust itself to give optimum performance in different types of missions and flight conditions. The thesis aims to study the morphing technology in relation to the aerodynamic performances. Different airfoil shapes have been investigated through the use of CFD program. The development of MATLAB program is also required to build the full understanding of parameters which relates to the change in airfoil shape. Therefore, Joukowski airfoil generator is coded. Then, through the full use of solid background on the shape and aerodynamic performances on each shape, morphing concept can be developed and studied. Based on cruise and loiter requirement for Global Hawk RQ-4A, ranges of airfoils which fulfill these requirements are taken into consideration with an objective of selecting the most suitable airfoil shape for these missions (i.e. cruise and loiter). The availability of mechanism and morphing materials are also taken as criteria in selecting suitable airfoil shapes. Once the candidate airfoils have been chosen for cruise and loiter condition, material selection process can be investigated. As a result, mechanisms which facilitate the change of airfoil shapes from cruise to loiter condition can be recommended for multi mission Global Hawk UAV.

Design and experimental validation of a control system for a morphing wing

AIAA Atmospheric Flight Mechanics Conference 2012, 2012

The paper presents a smart way to actuate and to control the airfoil shape of a morphing wing. The actuation system development is based on some smart material actuators like Shape Memory Alloys, disposed in two parallel actuation lines, and its control is performed by using a fuzzy logic PD controller of Mamdani type.

New aeroelastic studies for a morphing wing

INCAS BULLETIN, 2012

For this study, the upper surface of a rectangular finite aspect ratio wing, with a laminar airfoil cross-section, was made of a carbon-Kevlar composite material flexible skin. This flexible skin was morphed by use of Shape Memory Alloy actuators for 35 test cases characterized by combinations of Mach numbers, Reynolds numbers and angles of attack. The Mach numbers varied from 0.2 to 0.3 and the angles of attack ranged between -1° and 2°. The optimized airfoils were determined by use of the CFD XFoil code. The purpose of this aeroelastic study was to determine the flutter conditions to be avoided during wind tunnel tests. These studies show that aeroelastic instabilities for the morphing configurations considered appeared at Mach number 0.55, which was higher than the wind tunnel Mach number limit speed of 0.3. The wind tunnel tests could thus be performed safely in the 6'×9' wind tunnel at the Institute for Aerospace Research at the National Research Council Canada (IAR/NRC), where the new aeroelastic studies, applied on morphing wings, were validated.

Optimization of a Morphing Wing Based on Coupled Aerodynamic and Structural Constraints

AIAA Journal, 2009

This paper presents the work done in designing a morphing wing concept for a small experimental unmanned aerial vehicle (UAV), in order to improve the vehicle's performance over its intended speed range. The wing is designed with a multidisciplinary design optimization tool where an aerodynamic shape optimization code coupled with a structural morphing model is used to obtain a set of optimal wing shapes for minimum drag at different flight speeds. The optimization procedure is described as well as the structural model. The aerodynamic shape optimization code, which uses a viscous 2-dimensional panel method formulation coupled with a non-linear lifting-line algorithm and a sequential quadratic programming (SQP) optimization algorithm, is suitable for preliminary wing design optimization tasks. The morphing concept, based on changes in wing planform shape and wing section shape achieved by extending spars and telescopic ribs, is explained in detail. Comparisons between optimized fixed wing performance, optimal morphing wing performance and the performance of the wing obtained from the coupled aerodynamic-structural solution are presented. Estimates for the performance enhancements achieved by the UAV when fitted with this new morphing wing are also presented. Some conclusions on this concept are addressed with comments on the benefits and drawbacks of the morphing mechanism design.

Comparison of morphing wing strategies based upon aircraft performance impacts,”

2004

Conventional aircraft are designed for a specific mission and/or set of performance requirements. These requirements often cause the performance for certain mission segments to be compromised because of fixed wing geometry. While some devices, such as flaps, have been used to augment the wing geometry, new materials are being developed that could allow significant wing morphing capability. This paper demonstrates the impact of a morphing wing on aircraft performance and provides a method to compare various morphing strategies. = lift off n = gravity load factor T = thrust V = velocity W = aircraft weight

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