Msu composites2009
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Composite materials are increasingly being used in aircraft structures due to benefits like weight reduction, corrosion resistance, and tailorable properties. Regulations require material properties to account for manufacturing defects and the environment. The Boeing 787 uses composites for around 50% of its airframe structure. Composites are best suited to highly loaded parts where their high strength and stiffness provide critical weight savings.
![Shorthand Laminate Orientation Code
Tapes or Undirectional Tapes
[45/0/-45/902 /-45/0/45
• Each lamina is labeled by its ply orientation.
• Laminae are listed in sequence with the first number representing the
lamina to which the arrow is pointing.a a to c t e a o s po t g
• Individual adjacent laminae are separated by a slash if their angles
differ.
• Adjacent laminae of the same angle are depicted by a numerical
subscript indicating the total number of laminae which are laid up in
sequence at that angle
[45/0/-45/90] s
sequence at that angle.
• Each complete laminate is enclosed by brackets.
• When the laminate is symmetrical and has an even number on each
side of the plane of symmetry (known as the midplane) the code may
be shortened by listing only the angles from the arrow side to the
Tapes or undirectional tapes
Design and Analysis of Aircraft Structures 13-21
midplane. A subscript “S” is used to indicate that the code for only one
half of the laminate is shown.](https://image.slidesharecdn.com/msucomposites2009-161103023003/85/Msu-composites2009-21-320.jpg)
![Shorthand Laminate Orientation Code
Fabrics and Tapes and Fabrics
[(45)/(0)/(45)]
Midplane
• When plies of fabric are used in a laminate. The
angle of the fabric warp is used as the ply direction
angle. The fabric angle is enclosed in parentheses
[(45)/0(-45)/90]
Fabrics
g g p
to identify the ply as a fabric ply.
• When the laminate is composed of both fabric and
tape plies (a hybrid laminate). The parentheses
around the fabric plies will distinguish the fabric
Midplane
p g
plies from the tape plies.
• When the laminate is symmetrical and has an odd
number of plies, the center ply is overlined to
indicate that it is the midplane.
Tapes & Fabrics
Design and Analysis of Aircraft Structures 13-22
p](https://image.slidesharecdn.com/msucomposites2009-161103023003/85/Msu-composites2009-22-320.jpg)
Msu composites2009
- 1. Composite Materials for Aircraft StructuresComposite Materials for Aircraft Structures Dr. Douglas S. Cairns, Lysle A. Wood Distinguished Professor Department of Mechanical and Industrial Engineering Montana State Universityy ME 463 Composites, Fall 2009Fall 2009
- 2. Lysle Wood Professor • Goals of the Professorship – Make a positive and significant impact on aerospaceMake a positive and significant impact on aerospace technology nationally and in Montana – Provide support for aerospace related faculty d ldevelopment – Enhance student learning opportunities for aerospace related engineering careersrelated engineering careers Design and Analysis of Aircraft Structures 13-2
- 3. Cairns’ Background • Began composites career in 1978 as a Staff Engineer at the University of Wyoming – Characterization of compression fatigue mechanisms of F18 vertical stabilizer (AS1/3501-6) for Navy Hygrothermal characterization of Carbon Glass and Kevlar with Hercules 3501 6 for– Hygrothermal characterization of Carbon, Glass, and Kevlar with Hercules 3501-6 for Navy and Army • Senior Engineer, Hercules Aerospace, Magna UT (designed and analyzed space and aircraft structures manufactured from composite materials) • Ph.D. in Aeronautics and Astronautics, MIT, thesis on damage resistance andg damage tolerance due to impact damage in carbon/epoxy and kevlar/epoxy structures, research sponsored by FAA • Manager of Composites Technology, Hercules Materials Company – US largest manufacturer of structural carbon fibers materials for militar and commercial aerospace primar str ct ral applications– materials for military and commercial aerospace primary structural applications • Radius Engineering Board of Directors – since 1988 • Joined Mechanical and Industrial Engineering at Montana State University in 1995, began working on wind turbine blade structures, <$10/lb final part cost target based on aerospace technologyon aerospace technology • Teamed with Boeing engineers to develop and implement Aircraft Structures course at MSU • Former Chairman, AIAA Materials Technical Committee • Co-Chairman Damage Tolerance Committee NASA/ MIL HDBK 17 Composites Design and Analysis of Aircraft Structures 13-3 • Private Pilot Certificate, 2006 • FAA Consultant for developing composite materials specifications for General Aviation Aircraft
- 4. Introduction • Composite materials are used more and more forp primary structures in commercial, industrial, aerospace, marine, and recreational structures Design and Analysis of Aircraft Structures 13-4
- 5. Composites: • Composites materials consist of a fibrous reinforcements bonded together with a matrix materialg • Occur naturally in your bones, in wood, horns etc. • Allow the stiffness and strength of the material to change with direction of loading Design and Analysis of Aircraft Structures 13-5
- 6. The Hierarchy for Advanced Structural Materials • Begin as laboratory curiosity • Applications to expensive structures (often MilitaryApplications to expensive structures (often Military Aerospace) • Applications to stuff rich people buy • Applications to things you and I can afford K A ti R t i l lti t lKey Assumption: Raw materials are ultimately inexpensive and materials synthesis is ultimately inexpensivep Design and Analysis of Aircraft Structures 13-6
- 7. Case History- Aluminum • At one time, more rare than gold and silver; Kings and Queens wanted aluminum platesp • Very Expensive Applications – Art Deco furnishings in the 1920s and 1930s Milit i ft d i WW II– Military aircraft during WW II • Stuff that rich people buy (Post WW II through 1960s) – General Aviation – Boats – Bicycles Toda• Today – Aluminum BBQ grills at K-Mart – Aluminum shower curtain rods at hardware store Design and Analysis of Aircraft Structures 13-7
- 8. Composites: Fiberglass Fibers Kevlar Fibers Carbon Fibers Fiberglass Fibers Kevlar Fibers Design and Analysis of Aircraft Structures 13-8
- 9. Radius Engineering- Salt Lake City, Utah Radius developed the Trek carbon fiber bicycle used byRadius developed Swix carbon fiber G y y Lance Armstrongski poles; have been used by Gold medal Olympic skiers since 1990s Design and Analysis of Aircraft Structures 13-9
- 10. Discussion Objective • Provide a brief introduction to composite materials and structures in Airplane Structuresp Design and Analysis of Aircraft Structures 13-10
- 11. Composites are Damage Tolerant • F18 Midair Collision (Circa 2002, no injuries) Design and Analysis of Aircraft Structures 13-11
- 12. Composites are Damage Tolerant (cont.) Design and Analysis of Aircraft Structures 13-12
- 13. Composites are Damage Tolerant (cont.) Design and Analysis of Aircraft Structures 13-13
- 14. Composite Vertical Stabilizer and Rudder Damage Design and Analysis of Aircraft Structures 13-14
- 15. Composition of Composites Fiber/Filament Reinforcement CompositeMatrix • Good shear properties Low density • High strength High stiffness • High strength High stiffness• Low density• High stiffness • Low density • High stiffness • Good shear properties • Low density Design and Analysis of Aircraft Structures 13-15 y
- 16. Carbon is the Emperor Typical large tow properties Design and Analysis of Aircraft Structures 13-16
- 17. The Emperor’s New Clothes Two Basic Facts Hamper Application of Carbon Fibers to Primary Structure • Carbon Fiber is expensive; about 8X-10X E-glass fibersfibers • Much more sensitive to fiber mis-alignment fromg manufacturing process Design and Analysis of Aircraft Structures 13-17
- 18. Not Just An Academic Exercise Design and Analysis of Aircraft Structures 13-18 Consequence of Misalignment in Large, Composite Structure
- 19. To help protect your privacy, PowerPoint prevented this external picture from being automatically downloaded. To download and display this picture, click Options in the Message Bar, and then click Enable external content. The Emperor’s New Clothes Two Basic Facts Hamper Application of Carbon Fibers to Primary Structure updated 3:56 p.m. MT, Fri., Aug 14, 2009 Boeing Co. has discovered another problem with its long-delayed 787 jetliner, prompting the aircraft maker to halt production of fuselage sections at a factory in Italy. The Chicago-based company found microscopic wrinkles in the skin of the 787’s fuselage and ordered Italian supplier Alenia Aeronautica to stop making sections onfuselage and ordered Italian supplier Alenia Aeronautica to stop making sections on June 23, spokeswoman Lori Gunter said Friday. Boeing has started patching the areas. The plane, built for fuel efficiency from lightweight carbon composite parts, is a priority f B i it t l ith d i dli d id th l b l ifor Boeing as it struggles with dwindling orders amid the global recession. http://www.msnbc.msn.com/id/32415601/ns/business-aviation/ Design and Analysis of Aircraft Structures 13-19
- 20. Difficult to Control Manufacturing Defects in Production Design and Analysis of Aircraft Structures 13-20
- 21. Shorthand Laminate Orientation Code Tapes or Undirectional Tapes [45/0/-45/902 /-45/0/45 • Each lamina is labeled by its ply orientation. • Laminae are listed in sequence with the first number representing the lamina to which the arrow is pointing.a a to c t e a o s po t g • Individual adjacent laminae are separated by a slash if their angles differ. • Adjacent laminae of the same angle are depicted by a numerical subscript indicating the total number of laminae which are laid up in sequence at that angle [45/0/-45/90] s sequence at that angle. • Each complete laminate is enclosed by brackets. • When the laminate is symmetrical and has an even number on each side of the plane of symmetry (known as the midplane) the code may be shortened by listing only the angles from the arrow side to the Tapes or undirectional tapes Design and Analysis of Aircraft Structures 13-21 midplane. A subscript “S” is used to indicate that the code for only one half of the laminate is shown.
- 22. Shorthand Laminate Orientation Code Fabrics and Tapes and Fabrics [(45)/(0)/(45)] Midplane • When plies of fabric are used in a laminate. The angle of the fabric warp is used as the ply direction angle. The fabric angle is enclosed in parentheses [(45)/0(-45)/90] Fabrics g g p to identify the ply as a fabric ply. • When the laminate is composed of both fabric and tape plies (a hybrid laminate). The parentheses around the fabric plies will distinguish the fabric Midplane p g plies from the tape plies. • When the laminate is symmetrical and has an odd number of plies, the center ply is overlined to indicate that it is the midplane. Tapes & Fabrics Design and Analysis of Aircraft Structures 13-22 p
- 23. Fatigue Performance of Composites Exceeds That of Metals (Reference only) 1.00 Maximum 25/50/25/ Gr/Ep 0.75 cyclic stress/ultimate stress 0.50 Room temperature 0.25 7075-T6 aluminum temperature, dry • R = -1.0 • K1 = 3.0 0 102 103 104 105 106 107 Design and Analysis of Aircraft Structures 13-23 Cycles to failure
- 24. Reduced Corrosion Problems With Advanced Composites • Advanced composites do not corrode like metals— the combination of corrosion and fatigue crackingg g is a significant problem for aluminum commercial fuselage structure. Design and Analysis of Aircraft Structures 13-24
- 25. Corrosion Case History – Aloha Airlines • Low time airframe (but many Ground-Air-Ground cycles, 89,090 compression and decompression pressurization cycles from short hops) Design and Analysis of Aircraft Structures 13-25 compression and decompression pressurization cycles from short hops) • Operated in moist, warm environment (chemical processes exponential with temperature)
- 26. 767 Exterior Composite Parts Design and Analysis of Aircraft Structures 13-26
- 27. Honeycomb Usage Design and Analysis of Aircraft Structures 13-27
- 28. Summary—Advantages and Disadvantages of Composite Materials Advantages Disadvantages • Weight reduction (approximately 20-50%) • Some higher recurring costs • Higher nonrecurring costs • Corrosion resistance • Fatigue resistance • Higher material costs • Nonvisible impact damage • Tailorable mechanical properties S l th h ff t • Repairs are different than those to metal structure • Sales through offset • Lower assembly costs (fewer fasteners, etc.) • Isolation needed to prevent adjacent aluminum part galvanic corrosion Design and Analysis of Aircraft Structures 13-28 ( , )
- 29. Material and Process Specifications Material specifications Process specifications • Supplier qualification • Fiber requirements P i t • Storage and handling • Cure cycle L d b i• Prepreg requirements – Fiber volume – Resin chemistry – Mechanical properties • Layup and bagging procedures • In-process quality control • Postprocess quality control– Mechanical properties – Forms (tape, fabric) – Cure cycle – Quality controls • Postprocess quality control • Acceptable anomalies • Splicing – Manufacturing characteristics • Incoming and receiving tests Design and Analysis of Aircraft Structures 13-29
- 30. Building Block Approach Elements Joints Coupons Environment RT/Ambient (Th d ) Small Panels Full Airplane Structure Subcomponents (Thousands) (Hundreds) (Dozens) Large Panels Components Structure Coupons and Elements • Mechanical properties • Interlaminar properties St t ti Large Panels and Test Boxes • Validate design concepts • Verify analysis methods• Stress concentrations • Durability • Bolted Joints • Impact damage characterization E i t l f t • Verify analysis methods • Provide substantiating data for material design values • Demonstrate compliance with criteria • Demonstrate ability of finite element Materials The effects of temperature and moisture t d f i d i l d Analysis Thermal and moisture strains calculated using finite element model for each • Environmental factors • Demonstrate ability of finite element models to predict strain values Design and Analysis of Aircraft Structures 13-30 are accounted for in design values and strength properties. using finite element model for each critical condition.
- 31. FAA/JAA Requirements for Material Allowables • FAR 25.613, “Material Strength PropertiesFAR 25.613, Material Strength Properties – Statistical basis – Environmental effects accounted for – MIL-H-17B • FAR 25.615, “Design Properties”, g p – “A” basis for single load path – “B” basis for redundant structure • FAA AC 20-107A • JAR 25.613, 25.615, and 25.603 similar to Design and Analysis of Aircraft Structures 13-31 , , FAA regulations
- 32. FAA/JAA Regulations That Govern Structural Materials • FAR 25.603, “Materials”, – Suitability and durability established by tests – Conform to specifications that ensure strength – Takes into account environmental conditions • FAR 25.605, “Fabrication Methods” Fabrication methods must produce consistently– Fabrication methods must produce consistently sound structure (repeatability) – New methods must be substantiated by tests • FAR 25.609, “Protection of Structure” – Protected against deterioration or loss of strength • JAR 25 603 25 605 and 25 609 similar to FAA Design and Analysis of Aircraft Structures 13-32 JAR 25.603, 25.605, and 25.609 similar to FAA regulations
- 33. FAA/JAA Advisories That Govern Composite Materials • FAA AC 20-107A, “Composite Aircraft Structure”, p – Presents an acceptable—but not the only—means for certifying advanced composite structure • FAA AC 21-26, “Quality Control for the Manufacture of Composite Structure” – Presents an acceptable—but not the only—means for complying with the quality control requirement of FAR 21 • JAA ACJ 25.603, “Composite Aircraft Structure” Design and Analysis of Aircraft Structures 13-33 • Similar to FAA AC 20-107A
- 34. Strength Reduction of Advanced Composite Materials Pristine Materials R d i Processing anomalies • Surface irregularities • Splicing Reduction of the allowable stress • Waviness • Inclusions • Voids Damage Stress stress Damage • Visible damage • Nonvisible damage • Repair (holes, etc.) D i Allowable design Design • Environment Allowable strain reduction design region Strain Design and Analysis of Aircraft Structures 13-34 reductionS a
- 35. 777 Composite Primary Structure Certification Sequence Load Description Sequence Load Description 1 Limit proof Load 4 Strain surveyp a. Up bending b. Up bending/unsymmetric c. Down bending d. Down bending/ 5 6 7 y Fatigue spectrum Strain survey Ultimate load strain survey a. Stall buffet 2 g Unsymmetric e. Stall buffet (unsymmetric) Strain survey 8 b. Up bending c. Down bending Destruction test - d b di Design and Analysis of Aircraft Structures 13-35 Fatigue spectrum3 down bending
- 36. 787 Airplane Approximately 50% of the airframe is made from composites; a very bold move in the commercial aircraft industry Design and Analysis of Aircraft Structures 13-36
- 37. Design and Analysis of Aircraft Structures 13-37
- 38. Design and Analysis of Aircraft Structures 13-38
- 39. Boeing 787 Dreamliner Logistics Design and Analysis of Aircraft Structures 13-39
- 40. Summary • Composite parts used for aircraft applications are defined by – Material, process, and manufacturing specifications. – Material allowable (engineering definition). • All of these have a basis in regulatory requirements. • Most efficient use of advanced composites in aircraft• Most efficient use of advanced composites in aircraft structure is in applications with – Highly loaded parts with thick gages. – High fatigue loads (fuselage and wing structure, etc). – Areas susceptible to corrosion (fuselage, etc). Critical weight reduction (empennage wings fuselage etc)– Critical weight reduction (empennage, wings, fuselage, etc). • Use must be justified by weighing benefits against costs. Design and Analysis of Aircraft Structures 13-40