This document summarizes the challenges in designing and manufacturing wind turbine blades over time. It discusses: 1) How blade design has evolved from early 61.5m blades in 2004 to the current longest 73.5m and 88.4m blades, breaking records. 2) The validation methods used to test new blade concepts, including aerodynamic testing, fatigue testing, and other reliability tests. 3) Future challenges including designing even larger diameter blades with lower solidity and higher tip speeds within a narrow design space. Issues like erosion, high Reynolds numbers, and increased flexibility posing unknown aerodynamic implications. 4) The need for volume production to drive down costs through efficiency, quality, and

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CHALLENGES IN BLADE DESIGN AND
MANUFACTURING
Sandia Blade Work Shop 2016
Jesper Månsson
1

2. The
early years

3. 2004
61.5 m blade
introduced
(world’s longest
blade at the time)
1996
1st generation
Lightning-Protection
Vortex generators
2003
FutureBlade
technology
2002
Pre-bending
1999
VARTM
vacuum infusion
technology
2012
73.5 m blade
introduced
(world’s longest
blade at the time)

4. And we keep breaking records!
LM 88.4 P

5. Validated aerodynamics – large catalog of airfoils,
designed in an integrated design context
Glass fiber/polyester technology – validated and
scalable in a global manufacturing/sourcing setup
Carbon hybrid technology supporting existing
footprint – cost, performance and reliability
What have we achieved

6. Carefull validation of all steps
Field validation of spoiler
Full scale fatigue test
Lightning capture efficiency test
Rain erosion testing
Wind tunnel test
Mixed loading test of laminate
Coupon testing of Carbon laminates
6
Selection of tests
used to validate new
blade concepts

7. Design for manufacturing and Quality
Reliability, further supported by leading edge
protection and lightning protection.
Big blades LM 61.5P, LM 73.5P, LM 88,4P and long
offshore track record, but also high volume on
shore blade portfolio, scalable in our global
footprint.
What have we achieved

8. 8
What’s next

9. 9
Cost reductions for large wind turbines are possible by
applying integrated design philosophies which maximize
energy production under blade response constraints.
Larger diameter
Lower solidity
Higher tip speed
Design space is becoming more narrow and complex.
Especially when designing new blade for existing platforms.
Turbine component are getting even more optimized reducing design
space.
Challenging rotor designs

10. 10
Leading Edge erosion:
Erosion increases with V2
Erosion can lead to dramatic reduction in aerodynamic performance over
lifetime
LE protection systems have an impact on aerodynamic performance
In field erosive environment need to be classified
Non-validated and unknown aerodynamic effects:
High Reynolds numbers effects
High Mach numbers effects (compressibility)
How to implement
High tip speeds will lead to:

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Thick airfoils balanced for aerodynamic performance and
structural/aero-elastic implications
Supporting material technology and blade structure
Increased flexibility will lead to larger deflections and more
pronounced non-linear aero-elastic behavior with unknown
aerodynamic implications etc.
Validated design models to accommodate the challenges
Long slender blades calls for:

12. Diversified market requirements
Site specific vs IEC conditions – wind farms
Site specific designs
Intelligent blades
Use of continuous monitoring and control systems to optimize performance /cost,
and adaptively match site condition
Technology validation
Aerodynamics in laboratory and in field – feed back to design models
Blade structure testing both faster full scale and component level – challenge is typically
realistic loading
Further trends and focus areas
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13. Volume – is needed to drive down LCOE – efficiency, quality and
reliability
Scale - efficient manufacturing
NDT – faster, specific – feedback to statistical process control
Efficient manufacturing setup
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Thank you !
April 2016