1. 1 Inflatable structures Ir. J. Breukels Room 10.08 j.breukels@lr.tudelft.nl

2. 2 Inflatable structures Definition: An inflatable structure is a membrane structure which requires a tensile pre-stress, created by a pressure difference, to bear externally applied loads.

3. 3 Applications - Civil engineering - Aeronautics - Space

4. 4 Applications Civil engineering Property of Prospective Concepts, Switserland.

5. 5 Applications Civil engineering Property of Prospective Concepts, Switserland.

6. 6 Applications Civil engineering

7. 7 Applications Aeronautics Goodyear Inflatoplane

8. 8 Applications Aeronautics Prospective Concepts Stingray

9. 9 Applications Aeronautics GLOV (Gun Launched Observation Vehicle)

10. 10 Applications Aeronautics Inflatable kites

11. 11 Applications Space Inflatable re-entry vehicle

12. 12 Applications Space Inflatable solar concentrators

13. 13 Regular beams vs Inflatable beams Regular beam mechanics

14. 14 Regular beams vs Inflatable beams Inflatable beam mechanics

15. 15 The principle of wrinkling

16. 16 Wrinkling criteria Wrinkling criteria based on stress When σ = σ Wrinkling occurs bendingPressure

17. 17 Wrinkling criteria Wrinkling criteria based on strain

18. 18 Wrinkling propagation Wrinkling criteria based on strain

19. 19 Three states of an inflatable beam -Unwrinkled -Wrinkled -Collapsed

20. 20 Moment – Deflection curve

21. 21 Moment – Deflection curve

22. 22 Moment – Deflection curve

23. 23 Tapered beams

24. 24 Tensairity ® Synergetic combination of an airbeam with conventional cables and struts. Compression (strut) Tension (cable) Stabilization (air) Tensairity ® = Tension + Air + Integrity

25. 25 Tensairity ® Property of Prospective Concepts, Switserland.

26. 26 Tensairity ® Property of Prospective Concepts, Switserland. Tensairity ® demonstration bridge, 8m span, 3.5 t max. load

27. 27 Building wings with inflatables -Constructing airfoils with tubes -Sailwings

28. 28 Building wings with inflatables Constructing airfoils with tubes Pro:- Good airfoil shape Con:- Complex - Heavy

29. 29 Building wings with inflatables Constructing airfoils with tubes

30. 30 Building wings with inflatables Sailwings Pro:- Simple - light Con:- airfoil arbitrarily defined - only one tube to carry loads

31. 31 Building wings with inflatables Sailwings Straight tapered wing

32. 32 Building wings with inflatables Sailwings Elliptical wing

33. 33 Building wings with inflatables Sailwings Arcs (surfkites)

34. 34 Inflatable wings and control -Conventional control surfaces - Wing morphing

35. 35 Inflatable wings and control Nature’s solution to flight control

36. 36 Inflatable wings and control The early days

37. 37 How to morph an inflatable wing -Pressure variation -Nastic structures -Bump flattening -Trailing edge deflection

38. 38 How to morph an inflatable wing Pressure variation

39. 39 How to morph an inflatable wing Nastic structures

40. 40 How to morph an inflatable wing Nastic structures

41. 41 How to morph an inflatable wing Nastic structures

42. 42 How to morph an inflatable wing Bump flattening PZT -> Lead Zirconium Titrate

43. 43 How to morph an inflatable wing Bump flattening

44. 44 How to morph an inflatable wing Trailing edge deflection

45. 45 How to morph an inflatable wing Trailing edge deflection

46. 46 Questions?