This document summarizes advances in fiberglass properties for wind turbine blades. It discusses the evolution of glass fiber innovations from 1939 to present day, including the development of high modulus glass fibers with improved strength and corrosion resistance. It also outlines market trends driving demands for larger, more durable blades. Recent test results show increasing modulus and fatigue life of unidirectional fiberglass fabrics reinforced with high modulus glass fibers. Case studies demonstrate how these materials improve blade design and performance.

1. Copyright © 2014 Owens Corning. All Rights Reserved

2. Advances in Fiberglass Properties
for Wind Turbine Blades
Tom DeMint - Technical Marketing, Owens Corning
Marcus Liu - Technical Marketing, Owens Corning
Dave Hartman - Science & Technology, Owens Corning
Georg Adolphs - Technical Marketing, Owens Corning
Richard Veit - Science & Technology, Owens Corning
October 13-16, 2014
Orange County Convention Center
Orlando, FL

3. Evolution of Glass
Fiber Innovation
1939: E-glass - Boron added to glass for electrical properties
1965: R-glass - Higher performance
1968: S and S-2 Glass® - High strength and modulus (high melting power needed)
1974: AR-glass - Alkali resistant
1978: E-CR Glass - Corrosion resistant
1996: Advantex® ECR Glass and melting technology
- Boron free E-glass, ECR-glass (superior corrosion resistance to traditional E-glass)
- Breakthrough in melting technology for large capacity furnaces
2006: R and H-glass melting technology
- Combines High modulus glass and Advantex® - scale melting technology
2009: S-glass direct melt large capacity technology
- Production in large capacity furnaces with higher fiber homogeneity
2014: Windstrand® product line - Superior sizing chemistry
Large capacity
furnaces provide
industrial supply
of high
performance
glass fibers

4. Turbine Performance
Trends in the
Wind Energy Market

5. Market Evolution
ON-SHORE (HIGH WIND)
 Continued pressure to reduce
capital/operating costs
 Requires cost effective
solutions
 Reduce manufacturing and
operating costs
OFF-SHORE
 Large turbines (8MW)
 Larger blades
(75m - 80m, glass, carbon)
 Extreme environments
BETTER
RELIABILITY
25 year blade life
107 fatigue
load cycles
ON-SHORE (LOW WIND)
Longer blades to harvest
energy in low wind speed
regions and cold climates

6. The scaling problem
Blade Length
Blade Weight
 Aerodynamic loads scale up linearly with blade length,
which of itself might not require an increase in
material properties.
 However blade mass, gravitational loads, and fatigue
loads scale up exponentially with blade length.
Material requirements are increasing with
increasing blade length and mass.
Market needs higher Modulus/$, Strength/$

7. Material Data and
Advances in Properties
WindStrand®
2000
Advantex® E/ECR-glass
with advanced
sizing for epoxy
Windstrand®
3000
High modulus H-glass
with advanced
sizing for epoxy
Ultrablade®
G3
WS3000
UD Fabric
(eopxy)
New Products for Wind Turbine Blades

8. Unidirectional Fiberglass
Fabric/Epoxy Laminate
Modulus Trend
Source: Independent test lab results 2009-2014 (IMA Dresden, WMC, TPI Composites);
Momentive Epoxy resin RIMR 135/H137
Linear trend of increasing UD
glass fabric modulus with
increasing FVF approaching 50
Gpa using high modulus glass

9. Longitudinal Modulus Ex,
Measured vs. Theoretical
We observe good agreement between measured
and theoretical longitudinal laminate modulus Ex
Longitudinal Modulus Ex, Measured vs. Theoretical
-4 -3 -2 -1 0 1 2 3 4
99
95
90
80
70
60
50
40
30
20
10
5
1
Difference Measured-Theoretical Modulus E1 [GPa]
Percent
Fiber
ADV 78GPa
H 85GPa
Mean StDev N AD P
-0.2642 0.8623 9 0.427 0,241
0.04723 1.016 9 0.347 0,393
Normal - 95% CI
-2 -1 0 1 2
5
4
3
2
1
0
Difference measured-theoretical
Frequency
Mean -0.08867
StDev 1.004
N 22
Ex Measured- Ex Theoretical
Glass Bulk Modulus used for theoretical calculations
 Ebulk Advantex : 78 GPa
 Ebulk H-glass: 85 GPa

10. UD/Epoxy Static Strength
Properties, Characteristic Values
(95%/5% Confidence Interval)
Source: IMA Dresden test results 2009-2014 on UD Fabrics, Momentive Epoxy resin RIMR 135/H137
We see a correlation
between UD/epoxy tensile
and compressive strength

11. Laminate Behavior Transverse
to the Longitudinal Fibers
in Tension
Natural transverse contraction
can be constrained by adjacent
plies (often 90o plies) compared
to a pure UD lamina.
This constraint may lead to limited IFF cracks
transverse cracking, which may be
acceptable in some rotor blades.
However the average Inter Fiber
Fracture strength (IFF) is measured
and used for blade designs.

12. Tensile Load
Bearing Capability
E-glass UD H-glass EPW17 WS3000
Introduce WindStrand® “IFF Safety Factor” = 1.5
Source: IMA Dresden test results 2009-2014 on UD Fabrics,
Momentive Epoxy resin RIMR 135/H137
Lower is better
“Max Poisson” Transverse Strain
Transverse Strain Capability

13. Acoustic and Fracture Surface
Analysis of 45o Tension in
Advantex®/epoxy lamina Panels
E-glass UD/epoxy WindStrand® UD/epoxy
Source: OC WindStrand® fibers and data. Panels dry-wound
roving and infused using Momentive epoxy RIMR 135/H137
Better fiber matrix
adhesion leads
to higher transverse
strength

14. Static Longitudinal Tensile
Failure Modes, UD E-glass vs.
WindStrand® Fabric/Epoxy
Source: OC test data UD1800 Fabrics,
Momentive epoxy resin RIMR 035/038

15. Ultrablade® G3 vs G2 Fatigue
Performance (Stress Amplitude)
x
Higher Initial Static
Tensile Strength
Leads to Longer Life
Number of Cycles to Failure

16. Strength Knockdown from
Fiber to Laminate
Damage Accumulation
4500
4000
3500
3000
2500
2000
1500
1000
500
0
Vintage E-glass
Advantex®
1400
1200
1000
800
600
400
S-glass 0
0 1 2 3 4 5 6
Tensile Strength (MPa)
Tensile Strain (%)
Better fatigue performance leads to longer life and
lower design knockdowns from damage accumulation
Source: OC data on WS2000 UD Fabrics,
Momentive epoxy RIMR 135/H137
Vintage E-Glass
State-of-Art E-Glass
S-Glass
200
00 Tensile Strength 55%Vf (MPa) Knockdown
WS2000
Coupon
Mean
UD1200
Coupon
Mean
UD1200
Coupon
R(95%)
UD1200
Spar Cap
Mean
Fatigue
R=0.1
10^6
cycles
Advantex®

17. Fatigue Performance, E-glass
vs. H-glass UD Fabric/epoxy
4,0 4,5 5,0 5,5 6,0
700
650
600
550
500
450
400
350
Higher Initial Static Strength Leads to Longer Life
Source: Risoe / DTU tests 2013 on UD laminates,
Momentive Epoxy resin L135/H137
LOG (N)
Peak Stress [MPa]
FiFbiebregrlgaslass st ytpyepe
Fiber
ADV
H
Advantex® E
Advantex® E
Windstrand® H
Windstrand® H

18. Blade Designer and Manufacturer
Fitness-for-Use
Fitness-for-Use Characteristics Product Development Trend
Fabric
Handling
Molding
Performance
Mechanical
Performance
Many elements to the blade fabric FFU
• Increased longitudinal content
• “Steerable” UD fabric
• Unrolling characteristic SPC
• Short layup cycle time
• Smooth and aligned layup
• Suitable ply termination
• Efficient Infusion process
• Process Consistency
• Part Quality Consistency
• Reliable cycle time
• Reliable glass content
• Reliable part thickness
• 0o Tensile Modulus & Strength
• 90o Tensile IFF (Inter-fiber Fracture)
• Reliable Fatigue performance
• Polyester blades
• 50 GPa Longitudinal Modulus
• 1200 MPa 0o static tensile strength
• Target IFF >90% matrix strength
• Fatigue target > 50% static @106
cycles

19. Case Study of High
Modulus Glass Fabric

20. Case Study: Application
of Ultrablade® TRIAX G3
to Root Section
 Ultrablade® TRIAX G3 fabric construction and modulus
 Effect of fabric modulus on the blade root design
 Infusion behavior

21. Wind Turbine Blade Root
Connection Model (Samtech)
Single bolt and root laminate and bearing load modeled

22. Root Connection
Simulation Results
High Modulus Ultrablade® TRIAX reduces axial bold
load by 17% which can increase bold fatigue life

23. Epoxy Resin
Infusion Behavior
Area 9layers 19layers 29layers 39layers 49layers 59layers
Sample1-FWF 72.30% 72.20% 72.70% 72.80% 73.15% 73.38%
Sample2-FWF 72.35% 72.48% 72.52% 72.84% 72.98% 73.46%
Average FWF 0.72325 0.7234 0.7261 0.7282 0.73065 0.7342
Thickness 1.0998 1.0893 1.088 1.0882 1.0717 1.0716

24. Ultrablade® TRIAX
Market Interest
 Received first order. 350 root sections.
 Published GL-certified independent testing reports

25. Summary
 Independent laboratories confirm consistent and reliable results for
main design properties (E, S, fatigue life) of current glass reinforcements
and new products like WS3000 H-glass and Ultrablade® G3 fabrics.
 Similar linear best-fit slopes at higher initial static strength lead to longer life
 Glass reinforcements continue to offer cost effective design solutions
enabling longer and more efficient blades.
 We are pushing the UD glass/epoxy envelope, but we have not hit the upper limit
of glass blade length.
 Ultrablade® G3 fabrics offer a cost-effective alternative to carbon
 Since 2004, over 60 epoxy and polyester blades designs have been
launched around the world using H-glass and Ultrablade®.
 We expect design values of 50+GPa for
High Modulus UD glass/epoxy.

26. Thank you
Global Supply Quality Innovation