12/6/07 1/3/08 next generation carbon fibre composites patrik fernberg
TRANSCRIPT
12/6/07
1/3/08
Next generation carbon fibre composites
Patrik Fernberg
The Swerea group 2010
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Swerea IVF
Industrial product manufacturing, textile, polymers,
ceramics
Swerea KIMAB
Material use, material and process development, corrosion
Swerea MEFOS Metallurgy, metal heating
Swerea SICOMP Composite material, process and product development
Swerea SWECASTCast metals – product, material and process development
MD: Tomas ThorvaldssonOwner: Industry 53 %, RISE 47 %Turn over: 550 MSEKNo of employees: 450Company representation: 600 companies in different trade associations
Factfile - Swerea
Swerea SICOMP
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MD: Hans HanssonOwner: Swerea (100%)Turn over: 29 MSEKNo of employees: 31
Factfile - Swerea SICOMP
Piteå
Mölndal
Carbon fibre composites in primary load carrying structures
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Potentials for composites in aero engine application
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Composites can be used outside this line
Guide vanes
Fan case
Fan blades T < 120°C
Image presented by courtesy of Volvo Aero
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Desired composite characteristics
Damage tolerant composite material– material that can withstand high load (mechanical, thermal etc)
without defects or damage being created– material in which small defects do not easily grow to larger
critical defects• No manufacturing induced defects
• Good adhesion between fibre and polymer matrix
• Tough polymer matrix
Maintain load carrying capacity at high temperatures• polymer matrix resin with high glass transition temperature, Tg
Development of resins for CFRP
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Source: Smith PA In: Comprehensive Composite Materials, Kelly (Ed), Zweben (Ed)Images by courtesy of Per Hallander, Saab
Epoxy base
hardener hardenerEpoxy base
toughener
hardenerEpoxy base
toughener
Thermoplastic particles
hardenerEpoxy base
(Toughener)
(Thermoplastic particles)
Nanoparticles provides
enhanced or new properties
1st generation 2nd generation 3rd generation next generation !?
Potentials with nanocomposite resins
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Toughness enhancement Electrical conductivity Thermal conductivity
+ other functional properties (magnetic, barrier, shrinkage etc)
Source: Thostenson & Chou, Carbon (2006) Source: Thostenson & Chou, Carbon (2006)
Main obstacles – processing related
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Dispersion Viscosity increase Filtering (distribution)
Two epoxy-CNT nanocomposites (0.1% CNT)
Cross-section showing partially clogged flow channel between bundles
Increase by up to 3 orders of magnitude for CNF-suspensions
Source: Xu In: Processing and properties of nanocomposites, Advani (Ed)
Filtering of carbon nanotubes during resin transfer moulding
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Filtration No visual filtration
Vf ~ 58% Vf ~ 42%
More CNT filtering – influence of fibre architecture
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No MWCNTVf ~ 42 %
0.5% MWCNTVf ~ 42 %
0.5% MWCNTVf ~ 50 % Source: Nordlund, Fernberg, Lundström,
Composites Part A
Possible composite manufacturing solutions for nanocomposites
Technologies under investigation: Manufacturing with nanomodified prepreg tapes Position nanoparticles on fibre reinforcement Commingle nanocomposite and reinforcing fibres Coarse reinforcing structure to minimize flow resistance and
filtering
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Conceptual route: Tailor composite manufacturing for minimal flow length of nanodoped phase !!!
Manufacturing with nanomodified prepreg tapes
Some commercial systems becoming available Our current work is devoted to study processability issues and
consequences of low flow and air/gas permeability in doped prepreg Concept currently evaluated in FP7-project, Laysa, Interreg-project
Nakomate and to be further studied in NFFP5-project Multimap.
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CNT-doped epoxy film
clay-doped epoxy film
Nanoparticles on fibre reinforcement
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Carbon fiber after EPD treatment
CNT grown on to carbon fibresSource: Qian, Bismarck, Greenhalgh, Kalinka & Shaffer, Chem Mater, 2008
1. Grow particles on to fibres Particles integrated (covalent bonds) with fibres Tendency to strongly reduce fibre strength
2. Deposit or place particles on to fibres Electrophoretic deposition (EPD) Manual impregnation No covalent bonds between particles and fibres Concepts currently evaluated in FP7-project, Laysa and
NFFP5-project Kanon
Commingled fibres
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Types of yarns– Thermoplastic matrix fibres– Thermoset matrix fibres
Potential advantages– Particulate distribution– Short flow path (reduces problems
with high viscosity)
Concept to be evaluated/developed in FP7-project, FireResist. Starts 2010
Coarse reinforcing structure to minimize flow resistance and filtering
• Coarse reinforcement structure made from e.g. towpreg (preimpregnated fiber tow)
• Casting or resin transfer moulding of resin with high particle loadings
• Possible to reduce thermal expension of casting epoxies in high precision articles with moderate load carrying requirement
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Carbon fibre preform Preform impregnated with epoxy containing 50% (by volume) silica-particles (5 – 100 m]
Results from ongoing work Manufacturing concept:
Position nanoparticles on fibre reinforcement
Cross-ply laminates, [0/903]s
Tenax-E HTS 5631 Carbon fibre– Sigmatex UD-weave
– Surface weight 262 g/m2
HexFlow® RTM6 (Hexcel)– Monocomponent epoxy resin formulation
– Certified for use in aeronautic industry
– Tg 160 – 200°C (DMA)
MWCNT– Graphistrength CL1-020 by ARKEMA
– Provided as pre-dispersed aqueous dispersion
– (2g CNT / 100ml H20).
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Carbon fibre layup
0° 0°90°
Graphistrength CL 1-020
RTM-manufacturing of laminates
23-04-21 6th International ECNP Conference, Madrid 18
RTM-tool Laminate after demouldingImpregnation with H2O–based CNT dispersion
Preform preparation Composite manufacturing
Mechanical characterisation Apparent Interlaminar Shear Strength (ILSS)
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hw
PR4
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Standard EN2563
r – radius of support (3 mm);
h – thickness of the specimen (2 mm);
L – length of the specimen (20 mm);
lv – support span length (10 mm);
w – width of the specimen (10 mm)
Loading rate 1 mm/min
L
lv
h
r
The apparent shear stress at which failure occurs is given by:
PR is maximum force at failure
Results ILSS
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Laminate Average ILSS [MPa] Standard deviation [MPa] No of samples
Ref 73.6 7.7 7
Doped 83.2 2.4 8
13 % improvement with CNT-doping
Stiffness reduction due to crackingresults from tensile loading-unloading experiments
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!!! Strain at onset of transverse cracking decrease with CNT-doping !!!Potential explanations:• CNT-agglomerates acts as stress concentrations• too high CNT-content creates poorly impregnated interphase around fibres and poor adhesionPotential solution:• more “gentle” and precise deposition technique (electrophoretic deposition), ongoing work!!
SUMMARY
Integration of nanocomposites and nanotechnology in next generation fibre composites will provide improved or new features to the materials and components
A major technical obstacle is to adapt composite manufacturing technologies for particle (nano- and microsized) material systems
The route to overcome obstacle is to tailor composite manufacturing for minimal flow length of particle doped phase
Four different manufacturing concepts with such potential were proposed Encouraging results from work on RTM-manufacturing with CNT-doped
reinforcement were presented:
– Interlaminar shear strength improvements was confirmed
– lower resistance against transverse cracking Current work includes similar manufacturing and evaluation of laminates
with fabrics treated by electrophoretic deposition (KANON)
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Some sponsors
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NFFP5
KANON
Kolnanorörförstärkta kolfiberkompositer
Multifunctional Layers for Safer Aircraft Composite
Structures
Aerospace Nanotube Hybrid Composite Structures with
Sensing and Actuating Capabilities
COMETA
Advanced Polymeric COmpounds and METAL
Matrix Composites for Excellent Performances
in Machine Tools applications
RISE - Research Institutes of Sweden