TESTING MATERIALS FOR RENEWABLE ENERGY APPLICATIONS · mechanisms of failure in composite materials Chen X., Xu J.Z.: Structural failure analysis of wind turbines impacted by super

TESTING MATERIALS FOR RENEWABLE ENERGY APPLICATIONS

Ana Boyano

Mechanical Engineering Department

University of the Basque Country (UPV/EHU)

Spain

2

BACKGROUND: RENEWABLE ENERGIES, SUSTAINABILITY

DELAMINATION TESTING: composites for wind turbine blade materials

MECHANICAL TESTING: performance of PLA vs PLA+carbon fiber

SUMMARY AND CONCLUSION

3

EROI(Energy Returned on Energy Invested)

LCA(Life Cycle Assessment)

(“IPCC Fifth Assessment Report”, 2008)

4

Paris Climate Change Conference in 2015• Universal agreement• Limit the temperature rise to 2ºC

above pre-industrial levels• Lower emission targets every 5

years

shift to renewable energies

5

0102030405060708090

Nuclear (PWR) Hydro (med-size)

Coal Wind (E-66) Solar CSP Biomass

ERO

I

"Business as usual" and sustainable view

EROI (2013) EROI (2015)

369%

6

0

200

400

600

800

1000

1200

Emis

sion

s (g

CO2

eq/K

Wh)

Conservative and sustainable view

2011 research 2014 research

2180%

LCA LCA

7





8

TESTING MATERIALS FOR RENEWABLE ENERGY APPLICATIONS

BACKGROUND

Wind energy fundamentalissue to reduce the fossil fuel dependency

Picture taken from: https://www.mitchelltech.edu

9

INTRODUCTION

TRENDS:

Larger wind turbinesOffshore wind farms

Picture from geograph.org.uk Author David Dixon /

http://www.geograph.org.uk/photo/2391702http://www.geograph.org.uk/profile/43729

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DESIGN OF WIND TURBINE BLADES

Structural configuration

Material selection

11

INTRODUCTION

MATERIAL OPTIMUM FEATURES:

• high stiffness• strength • damage and loading resistances• low weight (low density)

COMPOSITESPicture from: http://www.compositestoday.com/category/green-composites/wind-energy-green-composites/

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BLADESmass

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MECHANISMS OF FAILURE IN COMPOSITE MATERIALS

Main failure modes in COMPOSITE LAMINATES

• Fibre failure

• Matrix failure

• Fibre-matrix debonding

• Inter-laminar failure (delamination)

• Buckling instability

14


• Inter-laminar failure Delamination

15


Chen X., Xu J.Z.: Structural failure analysis of wind turbines impacted by super typhoon usagi.Eng.Failure Anal. 60, 391-404 (2016).

16

Materials

Manufacturingprocess

StructuralDesign

Development of new composite

blades

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Sørensen, B. Materials and structures for wind turbine rotor blades–an overview, Proceedings of the17th international conference on composite materials (ICCM 17), Edinburgh, 2009; , pp. 31

18

LINEAR ELASTIC

FRACTURE MECHANICS

Composite laminates

can betailored

delamination

Mixed-mode I/II fracture is commonly observed

Mode I Mode II Mode III

Energy Criterion : G > Gc

G=GI+GII+GIII

G : Energy release rateGc : Fracture toughness

20

ENFR test:End Notched Flexure test with inserted Roller

21


22


23

Load +

Load application pointdisplacement

Compliance Crack length


23

Mixed-mode ratio GII/G

G=GI+GII

Mode I Mode II

GI GII

Initial crack tip position

Crack propagation

Crack propagation sequence


Crack propagation


Crack advance

Crack propagation

35

Unidirectional [0]16T300/F593

Carbon fiber Epoxi matrix

Specimen manufacturing

ID Nomenclature Initial GII/G (%)1 a40-R1-c5 652 a42-R0.9-c8 653 a42-R1.5-c0 674 a43-R0.9-c8 675 a41-R1-c5 686 a42-R1.5-c0 687 a45-R1-c8 688 a40-R1.25-c0 719 a43-R1.5-c0 7210 a46-R1.5-c0 77

37

Summary of experimental test conditions

0 1 2 3 40

50

100

150

200

250

300

Displacement(mm)

Load

(N)

1 2 3 4 5 6 7 8 9 10

38

Load - displacement

0 1 2 3 40

50

100

150

200

250

300

Displacement(mm)

Load

(N)

1 2 3 4 5 6 7 8 9 10

39

Load - displacement

0 1 2 3 40

50

100

150

200

250

300

Displacement(mm)

Load

(N)

1 2 3 4 5 6 7 8 9 10

40

Load - displacement

0 1 2 3 40

50

100

150

200

250

300

Displacement(mm)

Load

(N)

1 2 3 4 5 6 7 8 9 10

41

Load - displacement

42

0 2 4 6 8 10 12 140

50

100

150

200

Crack advance(mm)

GI (J

/m2 )

1 2 3 4 5 6 7 8 9 10

0 2 4 6 8 10 12 140

200

400

600

800

Crack advance(mm)

GII (

J/m2 )

1 2 3 4 5 6 7 8 9 10

GI GII

Mixed-mode ratioGII/G

Energy Criterion : G > Gc G : Energy release rateGc : Fracture toughness

LINEAR ELASTIC FRACTURE MECHANICS

I Ic

II IIc

G GG G

>>

1I IIIC IIC

G GG G

+ =

Mixed-modePure modes

GIc and GIIc (fracture toughness) material property)

44

200 400 600 800 100050

100

150

200

250

300

GII(J/m2)

GI(J

/m2 )

12345678910

1I IIIC IIC

G GG G

+ =

Test GIC (J/m2) GIIC (J/m2) R2 Geqc (J/m2)1 344 798 0.951 5242 309 1042 0.948 5683 304 1174 0.918 5984 298 1159 0.827 5885 252 1241 0.936 5596 274 1359 0.937 6117 237 1405 0.786 5778 265 986 0.882 5119 278 1312 0.753 604

10 277 1179 0.829 571Mean value 284 ± 31 1165 ± 184 571 ± 33

All data 263 1267 0.716 578Mode I 240 -Mode II - 1063

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Energy Criterion : G > Gc G : Energy release rateGc : Fracture toughness

LINEAR ELASTIC FRACTURE MECHANICS

( )( )

1/2

1/2

eq I IIc II Ic

eqc Ic IIc

G G G G G

G G G

= +

=eq eqcG G≥

ENFR test End Notched Flexure test with inserted Roller

I Ic

II IIc

G GG G

>>

1I IIIC IIC

G GG G

+ =

Mixed-modePure modes

47

0 5 10 15350

400

450

500

550

600

650

Crack advance(mm)

GEq

(J/m

2 )Geq Equivalent Energy Release Rate

48

ON THE MIXED MODE FRACTURE IN COMPOSITES WIND TURBINE BLADE MATRIALS CONCLUSIONS

• Wind turbine blades are made of layered materialsmixed mode failure

• ENFR test proposed for analyzing mixed-mode fracture

An equivalent energy release rate for mixed-mode propagation

proposed: experimental results show a good agreement

Future line:

Apply the results to

a cross section of a wind turbine blade

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Addition Manufacturing (AM)

50

FDM(Fused Deposition

Modelling)

MATERIALS

51

Poly Acid Lactic (PLA/1.75 mm)

Biodegradable

Flexural modulus 3,500 MPa

Bending strength 80 MPa

Shear modulus 2,400 MPa

MATERIALS

52

Carbon-fibre reinforced PLA (1.75 mm)

Low impact material

15% of fibres in weight

53

Specimen manufacturing: 3D printing

54

Specimen manufacturing: 3D printing

55

MECHANICAL TESTING3point bending testing fixture

ISO 14125:1998

56

Different spans (mm) 35, 50, 80,100, 120

Strain Range 0.05-0.25%

Results

Conclusions

1. Good compliance of expected material properties2. Increase of flexural modulus 83.16%3. Adequate to the use as low impacts materials for renewable structures

Still a long way

1027% bigger

CF-

PLA

1. Closer approximation to aluminium

2. Shear modulus and other mechanical modulus calculation for deeper researchesFu

ture

Thank you for your attention

TESTING MATERIALS FOR RENEWABLE ENERGY APPLICATIONSNúmero de diapositiva 2Número de diapositiva 3Número de diapositiva 4Número de diapositiva 5Número de diapositiva 6Número de diapositiva 7TESTING MATERIALS FOR RENEWABLE ENERGY APPLICATIONSNúmero de diapositiva 9Número de diapositiva 10Número de diapositiva 11Número de diapositiva 12Número de diapositiva 13Número de diapositiva 14Número de diapositiva 15Número de diapositiva 16Número de diapositiva 17Número de diapositiva 18Número de diapositiva 19Número de diapositiva 20Número de diapositiva 21Número de diapositiva 22Número de diapositiva 23Número de diapositiva 24Número de diapositiva 25Número de diapositiva 26Número de diapositiva 27Número de diapositiva 28Número de diapositiva 29Número de diapositiva 30Número de diapositiva 31Número de diapositiva 32Número de diapositiva 33Número de diapositiva 34Número de diapositiva 35Número de diapositiva 36Número de diapositiva 37Número de diapositiva 38Número de diapositiva 39Número de diapositiva 40Número de diapositiva 41Número de diapositiva 42Número de diapositiva 43Número de diapositiva 44Número de diapositiva 45Número de diapositiva 46Número de diapositiva 47ON THE MIXED MODE FRACTURE IN COMPOSITES �WIND TURBINE BLADE MATRIALSNúmero de diapositiva 49Número de diapositiva 50Número de diapositiva 51Número de diapositiva 52Número de diapositiva 53Número de diapositiva 54Número de diapositiva 55Número de diapositiva 56Número de diapositiva 57Número de diapositiva 58Número de diapositiva 59Número de diapositiva 60Número de diapositiva 61Número de diapositiva 62Número de diapositiva 63Número de diapositiva 64Número de diapositiva 65Número de diapositiva 66ConclusionsNúmero de diapositiva 68

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TESTING MATERIALS FOR RENEWABLE ENERGY APPLICATIONS · mechanisms of failure in composite materials Chen X., Xu J.Z.: Structural failure analysis of wind turbines impacted by super