Optimization Framework for Design of Morphing Wings

Transcription

1 Optimization Framework for Design of Morphing Wings Jian Yang, Raj Nangia & Jonathan Cooper Department of Aerospace Engineering, University of Bristol, UK & John Simpson Fraunhofer IBP, Germany AIAA Aviation 214 Atlanta 16-2 July 214

2 Traditional Aircraft Design Single point for the design Minimum weight Maximum C L /C D Suboptimal elsewhere

3 Aircraft Morphing Morphing, when applied to aerospace vehicles, is a technology or set of technologies applied to a vehicle that allow its characteristics to be changed to achieve better performance or to allow the vehicle to complete tasks it could not otherwise do. Jason Bowman, AFRL/VSSV 3

4 Configuration Morphing Change in planform Aircraft control Aircraft performance Change in mission High aspect-ratio glide Attack mode MFX 1, Span & Sweep 4

5 Configuration Morphing Baseline (Joshi et al., 24, AIAA) 5

6 Performance Morphing Change in structural properties Stiffness Camber Leading / trailing edge shape Aircraft control Aircraft performance Lift / drag Roll control Loads NASA, Active Flexible Wing (AFW) 6 NASA, Active Aeroelastic Wing (AAW)

7 Variable Stiffness Morphing Range of different adaptive stiffness methodologies to be explored Vary EI x, EI y, GJ, flexural axis using changes in internal structure Changes to spar orientation, rib position, spar cap position used in several previous EU projects 3AS, SMorph, NOVEMOR 7

8 Aims Develop an inverse design approach - optimise internal wing stiffness distribution - morphing capability. Meet optimal aerodynamic shape throughout the flight envelope Define the required changes in stiffness / elastic axis Minimize the amount of morphing Minimize the weight Satisfy any other constraints to be defined progressively

9 Inverse Design Approach Define required aerodynamic distributions Define required wing shapes Twist / camber / bending Optimise weight to determine stiffness distributions Evaluate required stiffness changes Determine morphing concept(s) to achieve stiffness changes 9

10 chordwise loading z/c x Wing Aerodynamic shape Via Lifting Surface VL or DL (lattice) (Lamar) mean camber for minimum drag Planform dimensions wing vortex panels Aspect ratio (AR) 12 Taper ratio.5 Sweep angle 1 degrees Semi-span 2 meters y 1.1 Mean camber lines x/c 2 y 4 6 Camber lines required to achieve M.74 loading x/c

11 Required CL 2 Aerodynamic shape design - Lifting Surface, Mach Effect CL vs Mach ΔCp distributions Cp M= Mach number Cp x/c y/s M= y/s x/c M=.4 Design for 4 different test cases thin lifting surface Cp x/c 1.5 y/s 1

12 x Aerodynamic shape Super-Critical (twist & Camber) - Panel & Euler (AR=12, Ma=.74) vortex panels Non-D y

13 Cp Aerodynamic shape Different approaches,.5 C L Euler x/s M.74, pressure distribution Cp Lifting Surface x/c y/s x 3 5 y Panel

14 Structural model t H Cross section t L t R d b c

15 Weight Optimisation Minimize weight Consider deflection/stress constraints & minimum gauge of design variables. Use optimality criteria method

16 Application: Aero design camber Cp Cp x Mach.74 Mach.6 Mach.4 Mach.25 16

17 C p (using M.74 camber) Mach.6 Mach.4 Mach.25 Cp Cp x 17

18 Spanwise loadings - effect of M CLL c/cav Xcp Non-D by CL Enlarged.74M camber. Evaluated at different test cases 18

19 Local AoA required to achieve reference loading of M.74 with M.74 camber 19

20 C p Distributions before --- & after adding twist --- Mach.6 Mach.4 Mach.25 Cp Cp x -3% Note -3% 2

21 weight (kg) y Structural Optimisation, (a) 5.74M solution process (b) Initial design Convergence Iteration number x Weight Convergence - fast Flex. axis varies as function of t R / t L 21

22 Predicted Jig shapes & Twist, different M Using M.74 camber Achieving M.74 pressure dist using wingbox twist only Mach.74 Mach.6 Mach.4 Mach.25 22

23 Morphing required (Twist only example from half span) Elastic twist GJ GJ 23

24 Morphing required (Twist & camber morphing example) Elastic twist GJ GJ 24

25 Morphing required (Twist & camber morphing example) Elastic twist GJ GJ Twist Note Strong Reduction Elastic twist GJ GJ Twist & camber 25

26 x Camber morphing case TE Morph: to achieve desired spanwise loading and reduce RBM y LE area TE area Wingbox area 26

27 LE morphing effects LE Morph: to reduce leading edge suction and flow separation 27

28 LE morphing 28

29 Mean camber shape Variations from M.74 to M.25 case 29

30 Conclusions Multiple point design useful for enhancing aircraft efficiency Adaptive wing / morphing concepts reviewed An inverse design approach to optimise the internal stiffness distribution & morphing capabilities Application to a regional aircraft wing Weight reductions achieved via structural optimisation Required morphing examined to meet the multi-design points Need a lot of twist morphing to achieve required shape over flight envelope Use of camber morphing reduces the amount of required twist 3

31 Ongoing Work Continue with aerodynamic shape determination Configuration / flight conditions (Panel, Euler) Winglet Controls Implement inverse approach on coupled-beam model, using more advanced Aero Panel & Euler, Bodies Determine required stiffness variations in terms of morphing approaches Investigate reasonable morphing requirements 31

32 Cp z PANAIR Results M.25, varying twist x y x 3 y 5 1

33 Euler results Design M.74 Off-design, Mach.6 33