IN SERVICE EXPERIENCEIN SERVICE EXPERIENCEAT DCNSAT 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

ABOUT DCNSABOUT DCNS

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ABOUT DCNSAT A GLANCE

12 900employees

2011 key figures

3,2 billion euros in order

intake

1/3 of revenue from int’l sales &

cooperationprogrammes

2,6 billion euros in revenue

A world leader in naval defence.An innovative player in energy.

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ABOUT DCNS

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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ABOUT DCNS

Naval defence activities� Surface ships and naval systems

� Submarines

Energy activities� Civil nuclear engineering (CNE)

� Marine renewable energies (MRE)

COMPOSITE STRUCTURESCOMPOSITE STRUCTURESAT DCNSAT DCNS

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COMPOSITE STRUCTURES AT DCNSMATERIALS & 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 DCNSSURFACE SHIPS

Replacement of mines hunters withwooden hull

Decrease of the magnetic signature

Minesweepers(CMT) – 70s

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COMPOSITE STRUCTURES AT DCNSSURFACE 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 DCNSSURFACE 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 towerSail plane

Antenna cover

SUMMARY OF ACCELERATED SUMMARY OF ACCELERATED AGEING TEST PROGRAMMESAGEING TEST PROGRAMMES

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SUMMARY OF ACCELERATED AGEING TEST PROGRAMMESAGEING 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 – compres sion – 3 point bending

� Physico-chemical tests : DSC – IRFT – water sorption – fire reaction tests – DMA

� SEM

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SUMMARY OF ACCELERATED AGEING TEST PROGRAMMESWATER SORPTION

( ) cbtaP +−= exp

( ) cbtaP +−= exp

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SUMMARY OF ACCELERATED AGEING TEST PROGRAMMESMAIN RESULTS

0,3 to 0,5 %2 to 3,5 %0,5 to 3 %Maximal water sorption

4 à 8°C5°C

Glass transition temperature

NoneNot evaluatedNoneChemical evolution

VINYLESTEREPOXYPOLYESTERImmersion at

60 – 70°C

of 40 %No changeTensile

of 30 to 40 %No changeInterlaminar shear

of 30 to 50 %No change3 point bending

STRENGTHMODULUSImmersion at

60 – 70°C

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SUMMARY OF ACCELERATED AGEING TEST PROGRAMMESMICROSCOPY

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SUMMARY OF ACCELERATED AGEING TEST PROGRAMMESCAVITATION EROSION – GLASS / EPOXY COMPOSITES

After step 6 (120 minat 20 to 89 m/s)

After step 9 (120 minat 20 to 89 m/s + 120 min at 89 m/s )

0

10

20

30

40

50

60

0 50 100 150 200 250 300

Time (min)

Vol

ume

loss

(m

m3)

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SUMMARY OF ACCELERATED AGEING TEST PROGRAMMESCAVITATION EROSION – GLASS / EPOXY COMPOSITES

Hand lay-up Infusion Prepreg

IN SERVICE EXPERIENCEIN SERVICE EXPERIENCE

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IN SERVICE EXPERIENCESURFACE SHIPS STRUCTURES

Debonding in sandwich panel

Impact in monolithic structure

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IN SERVICE EXPERIENCESURFACE SHIPS STRUCTURES

Decohesion

Cracks due tocorrosion ofmetallic inserts

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IN SERVICE EXPERIENCESURFACE 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 EXPERIENCESUBMARINES STRUCTURES

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IN SERVICE EXPERIENCEMAINTENANCE

Every 8 years : sanding, painting

Special maintenance : repairing

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IN SERVICE EXPERIENCEMECHANICAL PROPERTIES EVOLUTION

BAMO test structure (glass/polyester) – no paint / ge l-coat – no mechanical stress (except one explosion test) – 10 yea rs in Lorient : no evolution of the mechanical properties (above and below waterline )

CMT Andromède (glass/polyester) – gel-coat + antifoul ing 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 w ater

SM Le Terrible external deck (glass/polyester) – antif ouling paint – in service - 35 years :� Interlaminar shear strength : - 4 %

� Flexural strength : - 36 %

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IN SERVICE EXPERIENCESM LE TERRIBLE EXTERNAL DECK

NATURAL AGEING / NATURAL AGEING / ACCELERATED AGEING ACCELERATED AGEING

CORRELATIONCORRELATION

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NATURAL AGEING / ACCELERATED AGEING CORRELATIONFLEXURAL STRENGTH

FLEXURAL STRENGTHAGEING CORRESPONDING DURATIONS

0

20

40

60

80

100

120

140

160

0 2000 4000 6000 8000

Accelerated ageing (hours)

Nat

ural

age

ing

(yea

rs)

-36%

-41%

-28%

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NATURAL AGEING / ACCELERATED AGEING CORRELATIONINTERLAMINAR SHEAR STRENGTH

ILSS AGEING CORRESPONDING DURATIONS

0

20

40

60

80

100

120

140

160

0 500 1000 1500 2000

Accelerated ageing (hours)

Nat

ural

age

ing

(yea

rs)

-14%

-7%

-17%

CONCLUSIONCONCLUSION

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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 composit es 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

Excellent behaviour of composite structures in naval applications.

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THANK YOU FOR YOUR ATTENTIONTHANK YOU FOR YOUR ATTENTION