IN SERVICE EXPERIENCE IN SERVICE EXPERIENCE AT DCNS AT DCNS - - PowerPoint PPT Presentation
IFREMER-ONR Workshop DURABILITY OF COMPOSITES IN A MARINE ENVIRONMENT IN SERVICE EXPERIENCE IN SERVICE EXPERIENCE AT DCNS AT DCNS Frdrique LE LAY DCNS Research 24/08/2012 OVERVIEW ABOUT DCNS COMPOSITE STRUCTURES AT DCNS
Frédérique LE LAY – DCNS Research – 24/08/2012
IFREMER-ONR Workshop « DURABILITY OF COMPOSITES IN A MARINE ENVIRONMENT »
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OVERVIEW
ABOUT DCNS COMPOSITE STRUCTURES AT DCNS SUMMARY OF ACCELERATED AGEING TEST PROGRAMMES IN SERVICE EXPERIENCE NATURAL AGEING / ACCELERATED AGEING CORRELATION CONCLUSION
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ABOUT DCNS
AT A GLANCE
employees
2011 key figures
euros in order intake
from int’l sales & cooperation programmes
euros in revenue
A world leader in naval defence. An innovative player in energy.
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Over 350 years’ experience in naval defence 10 sites in France International presence Five areas of expertise
Naval architecture Engineering Shipyard management and ship assembly and integration Equipment design and production Through-life support (TLS)
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Naval defence activities
Surface ships and naval systems Submarines
Energy activities
Civil nuclear engineering (CNE) Marine renewable energies (MRE)
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COMPOSITE STRUCTURES AT DCNS MATERIALS & TECHNOLOGIES
Materials :
Resins : polyester, vinylester, epoxy, phenolic Fibers : glass, carbon, aramid Sandwich core : balsa, synthetic foams, syntactic foam
Production technologies :
Hand-lay up Prepreg Infusion Others : RTM, pultrusion
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COMPOSITE STRUCTURES AT DCNS SURFACE SHIPS
Replacement of mines hunters with wooden hull Decrease of the magnetic signature
Minesweepers (CMT) – 70s
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COMPOSITE STRUCTURES AT DCNS SURFACE SHIPS
Part of superstructures (83 T) Improved steel / GRP joint Radar compatibility of the steel / GRP joint
La Fayette class frigates (FLF) – 90s
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COMPOSITE STRUCTURES AT DCNS SURFACE SHIPS
Single integrated mast Options : composite topside, composite hull for fast versions
Corvettes / OPV Gowind (L’Adroit) - 2010
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COMPOSITE STRUCTURES AT DCNS SUBMARINES
Rudder Decks Sonar dome Conning tower Sail plane Antenna cover
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SUMMARY OF ACCELERATED AGEING TEST PROGRAMMES AGEING CONDITIONS & AGEING EVALUATION
Accelerated ageing conditions :
Temperature : from 40 to 100° C Duration : 500 – 1000 – 2000 – 4000 – 6000 – 8000 – 24000 hours Mechanical test samples – plates (500 X 500 mm) – edges protected by resin or silicon mastic Immersion : demineralized water – artificial salt water – natural salt water Salt spray Pressure : 1 – 60 – 400 bars Hygrothermal cycling (- 20°
C / + 70° C)
No loading or static flexural loading Two / One side(s) exposure
Ageing evaluation :
Mechanical tests : tensile – interlaminar shear – compression – 3 point bending Physico-chemical tests : DSC – IRFT – water sorption – fire reaction tests – DMA SEM
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SUMMARY OF ACCELERATED AGEING TEST PROGRAMMES WATER SORPTION
( )
c bt a P + − = exp
c bt a P + − = exp
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SUMMARY OF ACCELERATED AGEING TEST PROGRAMMES MAIN RESULTS
0,3 to 0,5 % 2 to 3,5 % 0,5 to 3 % Maximal water sorption 4 à 8° C 5° C Glass transition temperature None Not evaluated None Chemical evolution VINYLESTER EPOXY POLYESTER Immersion at 60 – 70° C
No change Tensile
No change Interlaminar shear
No change 3 point bending STRENGTH MODULUS Immersion at 60 – 70° C
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SUMMARY OF ACCELERATED AGEING TEST PROGRAMMES MICROSCOPY
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SUMMARY OF ACCELERATED AGEING TEST PROGRAMMES CAVITATION EROSION – GLASS / EPOXY COMPOSITES After step 6 (120 min at 20 to 89 m/s) After step 9 (120 min at 20 to 89 m/s + 120 min at 89 m/s )
10 20 30 40 50 60 50 100 150 200 250 300 Time (min) Volume loss (mm3)
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SUMMARY OF ACCELERATED AGEING TEST PROGRAMMES CAVITATION EROSION – GLASS / EPOXY COMPOSITES Hand lay-up Infusion Prepreg
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IN SERVICE EXPERIENCE SURFACE SHIPS STRUCTURES
Debonding in sandwich panel Impact in monolithic structure
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IN SERVICE EXPERIENCE SURFACE SHIPS STRUCTURES
Decohesion Cracks due to corrosion of metallic inserts
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IN SERVICE EXPERIENCE SURFACE SHIPS STRUCTURES
D area : loss of anti-fouling paint ; gelcoat ; surface filler ; 1-2 plies of woven roving 300 g/m² E area : 1-2 plies of woven roving 300 g/m²
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IN SERVICE EXPERIENCE SUBMARINES STRUCTURES
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IN SERVICE EXPERIENCE MAINTENANCE
Every 8 years : sanding, painting Special maintenance : repairing
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IN SERVICE EXPERIENCE MECHANICAL PROPERTIES EVOLUTION
BAMO test structure (glass/polyester) – no paint / gel-coat – no mechanical stress (except one explosion test) – 10 years in Lorient : no evolution of the mechanical properties (above and below waterline) CMT Andromède (glass/polyester) – gel-coat + antifouling paint – in service – 18 years : slight evolution of the mechanical properties
Interlaminar shear strength : - 5 à – 15 % in air ; - 6 à – 19 % in water Flexural strength : - 12 % in air ; - 28 % in water Compression modulus : - 14 % in air and in water Ultimate compression strength : - 14 % in air and in water
SM Le Terrible external deck (glass/polyester) – antifouling paint – in service - 35 years :
Interlaminar shear strength : - 4 % Flexural strength : - 36 %
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IN SERVICE EXPERIENCE SM LE TERRIBLE EXTERNAL DECK
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NATURAL AGEING / ACCELERATED AGEING CORRELATION FLEXURAL STRENGTH
FLEXURAL STRENGTH AGEING CORRESPONDING DURATIONS
20 40 60 80 100 120 140 160 2000 4000 6000 8000 Accelerated ageing (hours) Natural ageing (years)
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NATURAL AGEING / ACCELERATED AGEING CORRELATION INTERLAMINAR SHEAR STRENGTH
ILSS AGEING CORRESPONDING DURATIONS 20 40 60 80 100 120 140 160 500 1000 1500 2000 Accelerated ageing (hours) Natural ageing (years)
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CONCLUSION
Main ageing problems :
Corrosion of metallic inserts Holes in sandwich structures Impacts Assembly / removal Cavitation erosion
Main difficulties in evaluating the ageing of composites in service :
Lack of information concerning initial properties Imprecise history of the structure Very few opportunities to study real old structures Paint and gelcoat protection effects Materials evolution Difficulties in specimens preparation
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CONCLUSION
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