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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)