OPTIMAT BLADESWorkshop

OPTIMAT BLADES: OPTIMAT BLADES: RESULTS AND PERSPECTIVESRESULTS AND PERSPECTIVES

Arno van Wingerde

OPTIMAT BLADES

State of the ArtState of the Art Available results of research programmes and knowledge:

Uni-axial stress state (no complex stress state)

Mainly constant amplitude

Variable amplitude prediction appears to be not accurate

Thin coupons (no thick laminates)

Limited data on effect of external conditions

Different research programmes used different material and

specimens

Results of research programmes not consistent

No recommendations on repair

Limited data on condition assessment, residual strength

Current design recommendations have inherent limitations

OPTIMAT BLADES

Objectives & NumbersObjectives & Numbers

52 months until 30-04-’05 Total budget: 4.4 M€ Partners

R&D institutes: 10 Industries: 5 Certification bodies: 2

500 Person months 3000 Specimens tested > 900.000.000 Fatigue cycles > 40.000 Machine hours 150 Reports 25 Publications

OPTIMAT BLADES - numbers

Based on consistent material data including: Var. amplitude loading Complex stress states Residual stresses/life Extreme conditions Thick laminates Repair techniques

Accurate design recommendations for

optimised use of materials for rotor

blades with an improved reliability

OPTIMAT BLADES

OPTIMAT BLADES

PartnersPartners

10 R&D institutes5 Industries

2 Certification Bodies

OPTIMAT BLADES

ProjectProjectStructureStructure

Adm./ Financial Coordinator

Tech./ Scientific

Coordinator

Steering Committee

Manufacturers

Certification Bodies

Technical Committee

Task Group leaders &

coordination

Project Coordination Committee

All project partners

Task Group 1

VariableAmplitudeloading

Complex

StressState

ExtremeConditions

Thick

Laminates& Repair

Residual

Strength &

Cond. Ass.

Task Group 6Design recommendations

Task Group 2

Task Group 3

Task Group 4

Task Group 5

OPTIMAT BLADES

TG1: Variable Amplitude LoadingTG1: Variable Amplitude Loading

CLD of the material Test frequencies CA/VA/Block tests Update to the

Wisper spectrum, used for material tests to modern Wind turbines New Wisper

0

100

200

300

-600 -400 -200 0 200 400 600

Smean [MPa]

Sa

mp [

MP

a]

103 Cycles106 Cycles109 Cycles

Cycle

Leve

l Wisper

New WisperWisperX

OPTIMAT BLADES

TG2: Complex Stress StateTG2: Complex Stress State

Blades typically not uniaxial stress state

Materials sensitive to forces perpendicular to fibre

Influence upon strength unknown

Tests on tubes (tension-torsion)

Tests on Cruciforms

Static off-axis strength of OB_UD

-800

-600

-400

-200

0

200

400

600

800

1000

0 20 40 60 80 100

θο

σx [M

Pa]

Tsai-HahnPuck

OPTIMAT BLADES

TG3: Extreme ConditionsTG3: Extreme Conditions

At – 40°C: same or improved material results

At + 60°C: degraded material results

100% RH: degraded

6/12 submersed

Interlaminar strength

0%

50%

100%

150%

200%

-60 -40 -20 0 20 40 60 80

Temperature [°C]

Str

eng

th, r

elat

ive

to R

T [

%]

-40°C

+20°C

+60°C

OPTIMAT BLADES

TG4: Thick laminates & RepairsTG4: Thick laminates & Repairs Thick laminate: same fatigue performance

Static performance seemed lower Clamping of specimen

Repair: 1:50 scarf, about 70% static strength 1:40 much lower

More variation per batch

Scarf Repair at 2H/3

0.00

0.20

0.40

0.60

0.80

1.00

1.20

1 2 3 4 5Coupon Number

Stre

ngth

/ (A

vera

ge s

treng

th o

f ref

.)

Reference 1:50 1:75 1:100 1:25

2 m

long

OPTIMAT BLADES

TG5: Residual StrengthTG5: Residual Strength

Tested to fraction of Nf

20 % 50 % 80%

Then static tensile/ compressive test

R=0.1

R=-1

R=10R=0.1

R=-1

R=10

OPTIMAT BLADES

CLD diagrams – Linear GoodmanCLD diagrams – Linear Goodman

0

100

200

300

-600 -400 -200 0 200 400 600

Smean [MPa]

Sa

mp [

MP

a]

103 Cycles106 Cycles109 Cycles

0

100

200

300

-600 -400 -200 0 200 400 600

Smean [MPa]

Sa

mp [

MP

a]

103 Cycles106 Cycles109 Cycles

0

100

200

300

-600 -400 -200 0 200 400 600

Smean [MPa]

Sa

mp [

MP

a]

103 Cycles106 Cycles109 Cycles

0

100

200

300

-600 -400 -200 0 200 400 600

Smean [MPa]

Sa

mp [

MP

a]

103 Cycles106 Cycles109 Cycles

0

100

200

300

-600 -400 -200 0 200 400 600

Smean [MPa]

Sa

mp [

MP

a]

103 Cycles106 Cycles109 Cycles

OPTIMAT BLADES

0

100

200

300

-600 -400 -200 0 200 400 600

Smean [MPa]

Sa

mp [

MP

a]

103 Cycles106 Cycles109 Cycles

CLD diagrams – Shifted GoodmanCLD diagrams – Shifted Goodman

0

100

200

300

-600 -400 -200 0 200 400 600

Smean [MPa]

Sa

mp [

MP

a]

103 Cycles106 Cycles109 Cycles

0

100

200

300

-600 -400 -200 0 200 400 600

Smean [MPa]

Sam

p [

MP

a]

103 Cycles106 Cycles109 Cycles

0

100

200

300

-600 -400 -200 0 200 400 600

Smean [MPa]

Sa

mp [

MP

a]

103 Cycles106 Cycles109 Cycles

0

100

200

300

-600 -400 -200 0 200 400 600

Smean [MPa]

Sa

mp [

MP

a]

103 Cycles106 Cycles109 Cycles

0

100

200

300

-600 -400 -200 0 200 400 600

Smean [MPa]

Sa

mp [

MP

a]

103 Cycles106 Cycles109 Cycles

OPTIMAT BLADES

CLD diagrams – Multiple R valuesCLD diagrams – Multiple R values

0

100

200

300

-600 -400 -200 0 200 400 600

Smean [MPa]

Sa

mp [

MP

a]

103 Cycles106 Cycles109 Cycles

0

100

200

300

-600 -400 -200 0 200 400 600

Smean [MPa]

Sa

mp [

MP

a]

103 Cycles106 Cycles109 Cycles

0

100

200

300

-600 -400 -200 0 200 400 600

Smean [MPa]

Sa

mp [

MP

a]

103 Cycles106 Cycles109 Cycles

0

100

200

300

-600 -400 -200 0 200 400 600

Smean [MPa]

Sam

p [

MP

a]

103 Cycles106 Cycles109 Cycles

0

100

200

300

-600 -400 -200 0 200 400 600

Smean [MPa]

Sa

mp [

MP

a]

103 Cycles106 Cycles109 Cycles

0

100

200

300

-600 -400 -200 0 200 400 600

Smean [MPa]

Sa

mp [

MP

a]

103 Cycles106 Cycles109 Cycles

OPTIMAT BLADES

CLD diagrams – R = 0.1CLD diagrams – R = 0.1

0

100

200

300

-600 -400 -200 0 200 400 600

Smean [MPa]

Sa

mp [

MP

a]

103 Cycles106 Cycles109 Cycles

0

100

200

300

-600 -400 -200 0 200 400 600

Smean [MPa]

Sa

mp [

MP

a]

103 Cycles106 Cycles109 Cycles

0

100

200

300

-600 -400 -200 0 200 400 600

Smean [MPa]

Sa

mp [

MP

a]

103 Cycles106 Cycles109 Cycles

0

100

200

300

-600 -400 -200 0 200 400 600

Smean [MPa]

Sa

mp [

MP

a]

103 Cycles106 Cycles109 Cycles

0

100

200

300

-600 -400 -200 0 200 400 600

Smean [MPa]

Sam

p [

MP

a]

103 Cycles106 Cycles109 Cycles

0

100

200

300

-600 -400 -200 0 200 400 600

Smean [MPa]

Sa

mp [

MP

a]

103 Cycles106 Cycles109 Cycles

OPTIMAT BLADES

…….. And their consequences.. And their consequences

100

150

200

250

300

350

400

1 10 100 1000 10000 100000

Sequences to failure

Sm

ax

WISPER data

Multiple R-ratio (6 R-ratios)Single R; R=0.1

Linear GoodmanShifted Goodman

0

100

200

300

-600 -400 -200 0 200 400 600

Smean [MPa]

Sa

mp [

MP

a]

103 Cycles106 Cycles109 Cycles

0

100

200

300

-600 -400 -200 0 200 400 600

Smean [MPa]

Sa

mp [

MP

a]

103 Cycles106 Cycles109 Cycles

0

100

200

300

-600 -400 -200 0 200 400 600

Smean [MPa]

Sa

mp [

MP

a]

103 Cycles106 Cycles109 Cycles

0

100

200

300

-600 -400 -200 0 200 400 600

Smean [MPa]

Sa

mp [

MP

a]

103 Cycles106 Cycles109 Cycles

30%

2000%

OPTIMAT BLADES

Residual strength modelsResidual strength models

Relate static strength and fatigue behaviour Strength reduced per cycle, until load

exceeds strength

Results not significantly better than Miner and more complex models required

OPTIMAT BLADES

Test methodologyTest methodology

New “universal” test geometry Static tension Compression

About 20% lower than ideal value

Fatigue (all R values) Standard geometries

Better for comparison with earlier tests

Often no background provided

Rules hard to understand No universal geometry

Difficult for combined tests

ISO compression

OPTIMAT

Dogbone

55

55

35

40

25

3.5 2

6.5 7

OPTIMAT Geometry UD/MD

ISO tension

OPTIMAT BLADES

Lessons learntLessons learnt

Plate-to-plate and lab-to-lab variations are important in a project of this size More realistic assessment of scatter Preferably: production of all specimens first, then mix and

send out Not possible in practice

Establishing an alternative test geometry is difficult People perceive standards automatically as “better” even

when no background info is provided Material variations sometimes larger than

investigated influences Do not show up in lab analysis, such as Tg and vf Some plates worse in static strength, better in fatigue

OPTIMAT BLADES

OPTIDATOPTIDAT

0

5000

10000

15000

20000

25000

30000

35000

40000

45000

prior t

o 02-O

ct-0

3

02-Oct

-03

22-Oct

-03

31-Oct

-03

13-Nov-

03

14-Nov-

03

28-Nov-

03

26-Feb-0

4

12-May-

04

17-May-

04

25-May-

04

27-May-

04

09-Jun-0

4

11-J

un-04

18-Jun-0

4

18-Oct

-04

20-Dec-

04

04-Jan-0

5

14-Jan-0

5

28-Jan-0

5

04-Feb-0

5

12-Apr-0

5

28-Apr-0

5

23-Jun-0

5

01-Jul-0

5

08-Sep-0

5

19-Oct

-05

29-Nov-

05

12-Dec-

05

19-Jan-0

6

09-Feb-0

6

WMC DLR RAL RISØ CRES VUB UP VTT

Totals

18286

51411587 3884

17551673

7028

526

Tes

tin

g t

ime

[h

]

Total: 39880

Available (for a small fee) 1-5-2006: www.kc-wmc.nl

OPTIMAT BLADES

Agenda for the Workshop (1)Agenda for the Workshop (1)

Introduction to Optimat Blades

Recommendations of material tests

Determination of S-N lines

Fatigue life prediction

Biaxial stress state in blades

Biaxial Tests

Extreme conditions

Break

OPTIMAT BLADES

Agenda for the Workshop (2)Agenda for the Workshop (2)

Repair techniques & thick laminates Residual strength models OPTIDAT, the database of OPTIMAT Implementation of Technical Standards Panel discussion & input from industry

A new implementation of CLD

Finish: Workshop

Presentation of UPWIND ( 6th framework Wind Project)