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

Composites materials 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/m 3 ) 8000steel 2700aluminium 2000glass fibre reinforced plastics 1500carbon fibre reinforced plastics 2

Composites materials 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 3

Composites materials Basic rule-of-mixtures 1 Elastic properties (e.g. density or modulus) of composite calculated by rule-of-mixtures E C = η L. η O. V f. E f + V m. E m if the first term of the equation is large, the second term can be neglected

Composites materials Basic rule-of-mixtures 2 E C = modulus of composite η L = fibre length distribution factor η O = fibre orientation distribution factor V x = volume fraction of component x E x = modulus of component x subscripts f and m are fibre and matrix respectively

Composites materials Basic rule-of-mixtures 3 η L = fibre length distribution factor 1 for continuous fibres fractional for long fibres 0 if fibre below a “critical length”

Composites materials Variation of E with fibre length: fibre length distribution factor η l Cox shear-lag depends on G m : matrix modulus A f : fibre CSA E f : fibre modulus L: fibre length R: fibre separation R f : fibre radius < Shear < Tension

Composites materials Basic rule-of-mixtures 4 η O = fibre orientation distribution factor a weighted function of fibre alignment, essentially cos 4 θ: 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

Composites materials Variation of E with angle: fibre orientation distribution factor η o

Composites materials Basic rule-of-mixtures 5 V f = fibre volume fraction for random for fabrics for unidirectional consolidation pressure: no pressure gives low value above V f increases with pressure

Composites materials Basic rule-of-mixtures 6 E f = 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

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

Composites materials polyester resinε’ = % vinyl esterε’ = % epoxy resinε’ = % phenolic resinε’ = % data from NL Hancox, Fibre Composite Hybrid Materials, Elsevier, Matrix cracking max min

Composites materials Fibre fracture S/R-glassε’ = % …. E-glassε’ = 3.37 % ……….… Kevlar 49ε’ = 2.5 % …….………. HS-carbonε’ = 1.12 % ……………..… UHM-carbonε’ = 0.38 % …………………. data from NL Hancox, Fibre Composite Hybrid Materials, Elsevier, 1981.

Composites materials Fibre-matrix debonding Crack can run through (not shown), or around the fibre NB: ~12000 carbon or 1600 glass UD fibres/mm 2 a b c

Composites materials Fibre-matrix debonding:

Composites materials 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

Composites materials 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 forces as the fibre is pulled from the opposite face debonding and pullout absorbs high energies and results in a tough material

Composites materials 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

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

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

Composites materials 22 Formula 1

Composites materials 23 Road cars McLaren F1 road car

Composites materials 24 Road cars Lotus Elise S2 Reliant Robin 65 (2000)

Composites materials 25 Caparo Freestream T1 Graham Halstead UoP composites graduate – now with McLaren Racing

Composites materials 26 Dimitris Katsanis BEng CME graduate (project & Olympics)

Composites materials 27 Railways Inter-City 125 locomotive cab

Composites materials 28 Aircraft specifications

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

Composites materials 30 Aerospace: defence Joint Strike Fighter (F-35)

Composites materials 31 Biomimetics Common Tern Ivory Gull Squacco Stone Curlew

Composites materials 32 Grumman X-29 FSW aircraft 1984 to Aerospace: defence

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

Composites materials 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 MWh pa (3% Copenhagen's needs) construction March 2000 to March

Composites materials 35 Rehabilitation of civil engineering structures London Underground tunnels

Composites materials 36 Bridge structures Aberfeldy footbridge over River Tay

Composites materials 37 Internet resource for composites Teaching support materials for MATS324 Composites design and manufacture: Case studies: offshore structures, naval vessels, yacht hulls, canoes, sailcloth. Case studies: bridges

Composites materials 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

Composites materials 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

Composites materials 40 To contact me Dr John Summerscales  Reynolds Building Room 008     