teuwen e and p composites wind turbines

7/25/2019 Teuwen E and P Composites Wind Turbines

1/23

28-10-2009

Challenge the future

DelftUniversity ofTechnology

Vacuum infused thermoplasticcomposites for wind turbine blades

Julie Teuwen, Design and Production of Composites Structures


2/23

2Thermoplastic wind turbine blades

Introduction

WIND ENERGY:

Promising renewable energysource

Fast growing market share inenergy supply

WIND TURBINE BLADES:

Length > 50 m Life expectancy 20 years


3/23


Large Wind Turbine Blades

Dedicated Offshore Wind Power Systems:

Stronger and more constant wind Increasingly large blades to increase power output per turbine and

reduce cost per kWh

No noise-pollution and aesthetical issues

Larger blades require: Materials with higher specific properties (E/, /):

Carbon fibre based composites

More efficient structural design

mblade (Rblade)3

2.35


4/23


Current blade manufacturing technology

Material:

Glass fibres (NCFs) Thermoset resin

Process: Vacuum infusion

Prepregging Design:

2 skins and 1 spar

Structural bonding

Design

Material

Process


5/23


Alternative structural design Re-introduction of ribs:

Higher structural efficiency (E/)

Reduces buckling of the spar Provides attachment points and load paths for smart actuators,

control surfaces and sensors


6/23


Why thermoplastics?

Processing:

Forming Assembly by welding

Properties: Good impact properties

High toughness, also at low temperatures Abrasion resistant

Chemical resistant

Life cycle: Unlimited shelf-life of raw materials

Short production cycle time

Fully recyclable

Pre-cut laminatesheet material

Infra redheating panels

Rubber die

Metal die

Rubber press

Final thermoplasticcomposite part

Heating element

Clampconnection

Weldedparts

Voltmeter

Ampmeter


7/23


What still stands in the way? Costs:

Technology costs:

New technologies and expensive equipment

Material costs:

Need for intermediates

Processing:

High processing temperatures (>200C): High costs, thermal stresses

Melt pressing technology:

Limits part size and thickness

Properties: Fatigue performance:

Weak fiber-to-matrix bond

Monomer

Polymer

PowderGranules

Film Solution

Laminate Prepreg

Finalproduct

Traditi

onal

Pro

cessin

gof

Thermopla

stic

Com

posite

s


8/23


Vacuum infusion of thermoplasticcomposites

Reactive processing:

Processing:

From the monomer directly to the polymer

Large, thick, integrated parts

Commonly used technology

Below melting temperature of polymer

Properties: Improved fibre-to-matrix bond


9/23


Vacuum infusion of thermoplasticcomposites

Selection of resin: Low processing

temperature (150-180C)

Low viscosity (10 mPa.s)

Low price/performance(2-3/kg)

Anionic Polyamide-6: AP-Nylon

World wide availability

0,001

0,01

0,1

1

10

100

1000

10000

100000

0 50 100 150 200 250 300 350 400 450

Processing temperature [C]

Meltviscosity

[Pas]

epoxyvinylester

polyester

PMMA

PA-6

PBT

PA-12

PEK

ETPUPC

PMMA

PA-12

PA-6

PBTPPS

PES

PEI

PEEK

PEKK

Reactive processingof thermoset resins

Reactive processing ofthermoplastic resins

Melt processing ofthermoplastic polymers

0,001

0,01

0,1

1

10

100

1000

10000

100000

0 50 100 150 200 250 300 350 400 450

Processing temperature [C]

Meltviscosity

[Pas]

epoxyvinylester

polyester

PMMA

PA-6

PBT

PA-12

PEK

ETPUPC

PMMA

PA-12

PA-6

PBTPPS

PES

PEI

PEEK

PEKK

Reactive processingof thermoset resins

Reactive processing ofthermoplastic resins

Melt processing ofthermoplastic polymers

Selection of resin: Low processing

temperature

Low viscosity

Low price/performance


10/23


Alternative blade manufacturingtechnology


11/23


What is done on material development? Polymer chemistry and physics

Resin infusion process

Composite properties


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Polymer chemistry and physics

Resin composition

0

20

40

60

80

100

0 5 10 15 20 25 30 35 40

time [min]

Degreeofc

onversion[%].

Fast system

Slow systeminfusion

cure CAPROLACTAM

ACTIVATOR C20 INITIATOR C1


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Resin constitution Identify important parameters Understand & simulate the reaction

Polymerisation at different temperatures and comparison with pure -caprolactame,

inner temperature record, same beginning

0

50

100

150

200

250

0 200 400 600 800 1000 1200 1400 1600 1800 2000

time [s]

temperature[C]

pue CL, 140C, 1.measur.

140C, 1.measurement

150C, 1.measurement160C, 1.measurement

pure CL, 150C, 1.measur.

pure CL, 160C, 1.measur.

160C150C

140C


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Resin constitution Identify important parameters Understand & simulate the reaction Characterise the properties

Comparison with currently used material

2

1

0.1

0.2

f

m

Compared to injection molded PA-6

Condition Youngs modulus[GPa]

Maximum strength[MPa]

Strain at failure[%]

23C, dry 4.2 (+ 41%) 96 (+ 14%) 9 (-)23C, 50% RH 2.1 (+ 59%) 61 (+ 4%) 28 (-)

80C, dry 1.6 (+ 65%) 51 (+ 32%) 29 (-)


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Development of resin infusion process:

Fabric (fine and coarse weave) Glass

UD

Glass

110C

110C

160-180C

60 minutes

250 mbar


16/23



Development of resin infusion process Homogeneous properties: In flow direction

Through thickness

135

140

145

150

155

160

165

170

175

0 5 10 15 20 25

Time [min]

Tem

perature[C]

Tmould = 160C (inlet)

Tmould = 160C (center)

Tmould = 160C (outlet)

Outlet Inlet

-5

0

5

10

15

20

25

30

35

40

45

135 140 145 150 155 160 165 170 175 180 185

Temperature (C)

Layer Thermofoil+Carbon

CarbonResistiveThermofoilPlated press


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Development of vacuum infusion process

Homogeneous properties Identify important parameters Optimise infusion process Good mechanical properties

Good fibre-to-matrix bond

10

20

30

40

50

60

70

80

140 150 160 170 180 190 200

Mould temperature [C]

Interlaminarsh

earstrength[MPa]

APA-6 composite (unsized/outlet)

APA-6 composite (sized/outlet)


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Composite Properties

Static properties

(Dry conditioned)

0

100

200

300

400

500

600

Compressive strength Tensi le strength Shear strength

[MPa]

APA-6 Epoxy PA-6

0

5

10

15

20

25

30

Compressive modulus Tensile modulus Shear modulus

[GPa]

APA-6 Epoxy PA-6In dry state, APA-6 outperforms

all other reference material


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Static properties(moisture conditioned):

0

50

100

150

200

250

300

350

400

450

500

Compressive strength Tensile strength Shear strength

[MPa]

APA-6 Epoxy PA-6

0

5

10

15

20

25

30

Compressive modulus Tensile modulus Shear modulus

[GPa]

APA-6 Epoxy PA-6


20/23



Dynamic properties: APA-6 compositemanufactured at 180C has

better fatigue properties

than the melt processed PA-

6 composite:

Same toughness

Higher interfacial bond

strength0

50

100

150

200

250

300

350400

1.0E

+02

1.0E

+03

1.0E

+04

1.0E

+05

1.0E

+06

1.0E

+07

n

S[MPa]

APA-6 (180C)PA-6Epoxy


21/23


Conclusions

For rib/spar/skin-structures, thermoplastic composites arefavoured over thermoset composites. Parts can be rapidly meltprocessed and assembled through welding. Blades will be fullyrecyclable.

Vacuum infusion of thermoplastic composites is introduced to

overcome the classical drawbacks of these materials.

The cure of a semi-crystalline thermoplastic resin is morecomplicated than of a thermoset resin.

AP Nylon has a low viscosity (10 mPa.s), good availability, alow price (2-3 /kg), and a relatively low processing temperature(150-180C).


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Conclusions Homogeneous composites were obtained after optimisation of

infusion process. Temperature, pressure and time are the key

parameters.

Reactively processed PA-6 outperforms melt processed PA-6 inall temperatures and humidities tested.

Static properties of APA-6 composites are better than of theirHPA-6 and epoxy counterparts in dry conditions. When moistureconditioned, the performance of APA-6 composites drops rapidly.

Reactive processing of thermoplastic composites results in astrong interfacial bond strength and leads consequently tobetter fatigue performance compared to melt processing.


23/23


Vacuum infused thermoplastic

composites for wind turbine blades

Questions?

Julie Teuwen

Delft University of TechnologyFaculty of Aerospace Engineering

Design and Production of Composite Structures

teuwen e and p composites wind turbines

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