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Composite materials

Composite materials

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Composite materials

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  1. Composite materials John Summerscales Advanced Composites Manufacturing Centre School of Marine Science and Engineering University of Plymouth

  2. Newton’s second law of motion • Force = mass x acceleration (F = ma) • reduce mass • same performance with smaller engine, or • improved performance with the same engine • relative densities (vs water at 1000 kg/m3) • 8000 steel • 2700 aluminium • 2000 glass fibre reinforced plastics • 1500 carbon fibre reinforced plastics

  3. Materials • fibres • aramid: orange light tough (e,g, Kevlar) • carbon: black stiff brittle expensive conductor • glass: transparent tough inexpensive • polymers • thermoplastics: heat-form-cool • thermosets: liquid reactive mixture

  4. Basic rule-of-mixtures 1 • Elastic properties (e.g. density or modulus) of composite calculated by rule-of-mixtures • EC = ηL . ηO . Vf . Ef + Vm . Em • if the first term of the equation is large,the second term can be neglected

  5. Basic rule-of-mixtures 2 • EC= modulus of composite • ηL = fibre length distribution factor • ηO = fibre orientation distribution factor • Vx = volume fraction of component x • Ex = modulus of component x • subscripts f and m are fibre and matrix respectively

  6. Basic rule-of-mixtures 3 ηL = fibre length distribution factor • 1 for continuous fibres • fractional for long fibres • 0 if fibre below a “critical length”

  7. < Tension < Shear Variation of E with fibre length:fibre length distribution factor ηl • Cox shear-lag • depends on • Gm: matrix modulus • Af: fibre CSA • Ef: fibre modulus • L: fibre length • R: fibre separation • Rf: fibre radius

  8. Basic rule-of-mixtures 4 ηO = fibre orientation distribution factor • a weighted function of fibre alignment, essentially cos4θ: • 1 for unidirectional • 1/2 for biaxial aligned with the stress • 3/8 for random in-plane • 1/4 for biaxial fabric on the bias angle

  9. Variation of E with angle:fibre orientation distribution factor ηo

  10. Basic rule-of-mixtures 5 • Vf = fibre volume fraction • 0.15-0.3 for random • 0.35-0.6 for fabrics • 0.6-0.75 for unidirectional • consolidation pressure: • no pressure gives low value above • Vf increases with pressure

  11. Basic rule-of-mixtures 6 • Ef = elastic modulus of fibre • glass = ~70 GPa (equivalent to aluminium) • aramid = ~140 GPa • carbon = ~210 GPa (equivalent to steel) • figures above are lowest values i.e. for standard fibres

  12. Glass transition temperature (Tg) • Tm = crystalline melting point • Temperature at whichsegmental motion of the chain is frozen out • below Tg polymer is elastic/brittle • above Tg polymer is viscoelastic/tough • more rigorous than heat distortion temperature • Tg for thermoplastics = Tm - ~200°C • Tg for thermosets follows cure temp.

  13. Matrix cracking maxmin • polyester resin ε’ = 0.9-4.0 % • vinyl ester ε’ = 1.0-4.0 % • epoxy resin ε’ = 1.0-3.5 % • phenolic resin ε’ = 0.5-1.0 % • data from NL Hancox, Fibre Composite Hybrid Materials, Elsevier, 1981.

  14. Fibre fracture • S/R-glass ε’ = 4.6-5.2 % …. • E-glass ε’ = 3.37 % ……….… • Kevlar 49 ε’ = 2.5 % …….………. • HS-carbon ε’ = 1.12 % ……………..… • UHM-carbon ε’ = 0.38 % …………………. • data from NL Hancox, Fibre Composite Hybrid Materials, Elsevier, 1981.

  15. Fibre-matrix debonding • Crack can run through (not shown), or around the fibre • NB: ~12000 carbon or 1600 glass UD fibres/mm2 c b a

  16. Fibre-matrix debonding:

  17. Delamination of layers • one layer is a lamina (plural = laminae) • several layers in a composite is a laminate • separation of the layers is delamination • to avoid delamination • 3-D reinforcement (often woven or stitched) • Z-pinning

  18. Fibre pullout • as parts of a fractured composite separate, the fibres which have debonded can fracture remote from principal fracture plane. • energy is absorbed by frictional forcesas the fibre is pulled from the opposite face • debonding and pullout absorbs high energies and results in a tough material

  19. Marine Composites: state-of-the-art • Swedish Navy Visby stealth corvette • 600 tons - 72 m long - FRP sandwich • Royal Navy mine counter measures vessels • 725 tons - 60 m long - monolithic GRP

  20. Marine Composites: state-of-the-art • VT Mirabella V sloop rigged yacht • 740 tonnes - 75.2 m long - 90 m mast • CFRP/GRP/polyolefin foam

  21. Marine leisure • Power-boats: racing/“gin palaces” • Sailing: ocean racing thro’ boating lake • Diving: wet-suits and air-tanks • EnvironComp (Halmatic GFRPP boat) • EU BE-3152 : BRPR-CT96-0228 • Research, development and evaluation of environmentally friendly advanced thermoplastic composites for the manufacture of large surface area structures

  22. Formula 1 • http://www.mclaren.co.uk/ • http://ourworld.compuserve.com/homepages/john_hopkinson/williams.htm

  23. Road cars • McLaren F1 road car http://www.cottingham.co.uk/macf1/road.htm

  24. Road cars • Lotus Elise S2 • Reliant Robin 65 (2000)

  25. Caparo Freestream T1 Graham HalsteadUoP composites graduate – now with McLaren Racing

  26. Dimitris Katsanis • BEng CME graduate (project & Olympics)

  27. Railways • Inter-City 125 locomotive cab http://home-2.worldonline.nl/~fgvdhurk/hst.htm

  28. Aircraft specifications

  29. Aerospace: Airbus A380 The world’s only twin-deck, four-aisle airlinerThe airlines’ solution to growing demand for air travelThe green giant, more fuel-efficient than your carThe dedicated three-deck 150 tonne long-range freighter

  30. Aerospace: defence • Joint Strike Fighter (F-35)

  31. Biomimeticshttp://www.rarebirdphotography.co.uk Common Tern Ivory Gull Squacco Stone Curlew

  32. Aerospace: defence • Grumman X-29 FSW aircraft 1984 to 1992 http://www.globalsecurity.org/military/systems/aircraft/x-29.htm

  33. Wind energy Vestas Blades UK Limited (formerly NEG-Micon ) Isle of Wight wind turbine blades up to 42 m developed with ACMC Plymouth

  34. Key features: offshore wind farm • Middelgrunden • windfarm length of 3.4 km near Copenhagen, Denmark • 20 turbines, each 2 MW • 60 m hub height, 76 m rotor diameter. • water depth of 2-6 metres • modified corrosion protection,internal climate control, built-in service cranes. • 85 000 MWh pa (3% Copenhagen's needs) • construction March 2000 to March 2001 • http://www.worldenergy.org/wec-geis/publications/reports/ser/wind/wind.asp

  35. Rehabilitation of civil engineering structures • London Underground tunnels

  36. Bridge structures • Aberfeldy footbridge over River Tay

  37. Internet resource for composites Teaching support materials for MATS324Composites design and manufacture:https://www.fose1.plymouth.ac.uk/sme/mats347 Case studies: offshore structures, naval vessels, yacht hulls, canoes, sailcloth.https://www.fose1.plymouth.ac.uk/sme/composites/marine.htm Case studies: bridges https://www.fose1.plymouth.ac.uk/sme/composites/bridges.htm

  38. BEng Mechanical Engineering with Composites • Year 1 common with Mech Eng/Marine Tech • Year 2 common with Mech Eng • Year 3 in industry ? • Year 4: 40 credits for composites pathway • composites design and manufacture (20 credits) • selection, characterisation, stress analysis & manufacture • composites engineering (20 credits practical) • mountain bike suspension/bike front forks • yacht winch handle • skaters trolley/dinghy launching trolley

  39. Composites graduate destinations • Aerospace • Air France, Airbus (UK & F), BAe, GKN etc • Formula 1 • Benetton, McLaren, Team Toyota, Williams • Automotive • Aston Martin Lagonda, BMW (D), • Pininfarina (D), TWR Leafield • Marine • Carbospars (ES), Princess, Sunseeker

  40. Professional registration • BEng/MEng (honours)Mechanical Engineering with Compositesis accredited for Chartered Engineer withIOM3 (which hosts British Composites Society) and IMechE

  41. To contact me • Dr John Summerscales • Reynolds Building Room 008  01752.5.86150  07753.56.8733 • 01752.5.86101 • jsummerscales@plymouth.ac.uk • http://www.plymouth.ac.uk/staff/jsummerscales