1. Dr. Benjamin K. S. Woods 13/10/2014 2. Fish Bone Active Camber Morphing Airfoil Key Features of the FishBAC: Highly anisotropic compliant core Thin central bending beam spine Stringers branch off to support skin Soft in camber direction, stiff spanwise Pre-tensioned elastomeric skin Fiber reinforced elastomeric matrix composite Antagonistic tendon drive system Non-backdriveable spooling pulley system Rigid main spar Carries global loads 3. FishBAC work to date 3 generations of demonstrators Structural analysis and testing Aerodynamic simulation (low and high-fidelity) Wind tunnel testing 20-25% increase in Cl/Cd over a traditional trailing edge flap Actuation system design Fluid-Structure Interaction analysis Multi-objective optimization Mass, Cl/Cd,energy GA wrapped around FSI FishBAC Mk 3.0 FishBAC Mk 2.0 4. FishBAC Work to Date example results Wind tunnel tests show a 20-25% increase in L/D compared to flaps for 0 10 Good agreement between low and high fidelity aero models Analytical model of stiffness behaviour well validated Fluid-Structure Interaction analysis predicts equilibrium deformation under coupled aero and actuation loads (not yet validated) Analytical model of antagonistic tendon actuation system has been validated 5. Adaptive Aspect Ratio (AdAR) Wing Concept Adar is Welsh for bird the inspiration for the smooth continuous span change we seek Capable of 100% increase in span of active section Compliant skin over mechanical core Four key technologies: Elastomeric Matrix Composite (EMC) skin Telescopic rectangular spar Sliding ribs Strap drive 6. Design Configuration - The telescoping spar is rectangular and overlaps into the non-morphing region - The ribs slide over the spar and have max/min distance constraints - The EMC skin is bonded onto the ribs - Pre-tension is applied before bonding 0.5 m1.0 m 1.0 m 1.0 m Retracted state Extended state -A kevlar strap runs from the inner spar to the outer and then to the wing root -Strap tension drives extension -The strap winds onto a motor driven drum -Hyperelastic skin stretches over 130% The skin is by far the most important design driver as you will see in Teds talk tomorrow 7. Morphing Flap Transition The discrete ends of current trailing edge flaps are a source of drag and noise SUs answer: compliance based, passive transition Trailing edge deflection and angle are coupled structurally: smooth and continuous Tensioned elastomeric skin surface High chordwise and through-thickness stiffness, low camber and spanwise stiffness Applying for an EPO Patent cant show you the cool bits yet! Airbus A380: lots of flap gaps! Rigid end Flap end Smooth and continuous 3D morphing Modular design: retrofitable and replaceable 8. Negative Stiffness for Passive Energy Balancing - Concept Compliant structures have intrinsic elastic stiffness Creates a severe design trade off: we want high structural stiffness to give good shape control and aeroelastic response we also want low actuation requirements to minimize mass and power penalties What if we could passively balance the stiffness of the compliant structure with a negative stiffness spring? 9. Spiral Pulley Negative Stiffness Concept SPNS Device: a positive stiffness linear spring acting through a spiral pulley which rapidly increases the moment arm of the force to turn decreasing linear force into increasing torque with rotation. Drive spring and load spring are in equilibrium over a wide range of rotations 90% reduction in energy required 92% reduction in max torque 10. Conclusions and Outlook We have created a family of solutions with shared DNA: Compliance based exploiting anisotropy to focus compliance Simplicity of design prescribed architectures Not afraid to strain! reinforced elastomers create smooth continuous surfaces Varying degrees of progress made in different areas FishBAC is currently the furthest along, but were making good progress on the others Are looking to continue and expand our work Want to explore a wide range of applications Commercial airliners, UAVs, rotorcraft, wind turbines, tidal stream turbines, etc. Keen to collaborate with government, academic, and industrial partners 11. Cheers! Dr. Benjamin K. S. Woods b.k.s.woods@swansea.ac.uk