9-24-CX-Rev-ASME presentation-final
Transcript of 9-24-CX-Rev-ASME presentation-final
Structural Performance of A Glass/Polyester Composite
Wind Turbine Blade with Flatback and Thick Airfoils
Authors: X. Chen*, Z.W. Qin, X.L. Zhao, J.Z. Xu Corresponding author: X. Chen ([email protected])
Presenter: Z.W. Qin ([email protected])
IET-Wind
National Energy Wind Turbine Blade R&D Center
Institute of Engineering Thermophysics (IET)
Chinese Academy of Sciences (CAS)
IET-Wind at a Glance
- 2 wind tunnels: 0.5x0.5x5 m, 2.5x0.8x6 m
3x4x20 m (under construction)
- PIV experimental system
- Pressure Scanner
- Constant temperature anemometer system
- Computational cluster: 38 cpus, 200 cores
- Commercial and in-house CFD codes
Aerodynamics & Aero-elastics & Aero-acoustics (3As)
Structures & Materials
Manufacturing
Field Testing and Validation
- MTS bi-axial static/fatigue testing platform (up to100m)
(under construction)
- Bending-Torsion component testing rig
- Material and components fatigue testing machine
- Lightning test equipment
- FORCE AMS-64 blade defect scanner
- 100kW WT blade testing platform
- 3As/structure/power output testing
- New design concept validation
- Blades up to 70 m
IET-Wind Members:
Director: Prof. J.Z. Xu
Profs.: 7
Asso. Profs.: 8
Ass. Profs.: 14
Other staffs and engineers: 13
Phd and Msc Students: 30+
Wind Energy Development in China
China’s 2020 target:
In total: 200 GW, Offshore: 30 GW
Remaining Challenges:
Failure/buckling of transition region
Failure/buckling of trailing edge
Delamination of spar caps
Overall stiffness of the blades
Flatback airfoil
Sharp TE airfoil
Thick airfoil
Thin airfoil
Thin airfoil
Spar cap with transversely uniform thickness
Spar cap with transversely stepped thickness
Fig. 1 Structural features of blades proposed by CAS
IET-Wind New Concepts of Blade Design
Expected advantages
• Improved local buckling resistance
• Large stiffness and strength in the mid-span region
• Strong root transition region
• Improved aerodynamic performance
• Reduced manufacture cost
Manufacturing of 10.3 m Prototype Blade
Certification and Failure Test
Edgewise bending:
0%40%60%80%100% Pdextreme
Flapwise bending:
0%40%60%80%100%PdextremeBlade failure
8m 4m
8m 4m
0.00
0.02
0.04
0.06
0.08
0.10
0.12
0 2 4 6 8 10 12
Defl
ecti
on (
m)
Blade span (m)
Test
Classic Beam Theory100%
80%
60%
40%
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
0 2 4 6 8 10 12
Defl
ecti
on (
m)
Blade span (m)
Test
Classic Beam Theory
210%
180%
140%
100%
80%
60%
40%
Edgewise Flapwise
Blade Deflection
Blade Strains
0%
50%
100%
150%
200%
250%
-8000 -6000 -4000 -2000 0 2000 4000 6000 8000
% T
est
lo
ad
Spar cap strains (μ)
SS-2.0mPS-2.0mSS-5.5mPS-5.5m
Failure load=220%
0%
50%
100%
150%
200%
250%
-1500 -1000 -500 0 500 1000
% T
est
lo
ad
Aft panel strains (μ)
Failure load=220%
Fig. 8 Strains on aft panels at 2 m
0%
50%
100%
150%
200%
250%
-200 -150 -100 -50 0 50 100 150 200
% T
est
lo
ad
Shear web strains (μ)
Failure load=220%
Fig. 9 Strains on shear web at 2 m
0%
50%
100%
150%
200%
250%
-600 -450 -300 -150 0 150 300
% T
est
lo
ad
Flatback strains (μ)
Failure load=220%
Fig. 10 Strains on flatback at 2 m
Blade Failure Characteristics
8m 4m
Blade failure at the mid-span of the blade at 220%Pdextreme
with UD laminate crushing in the spar cap.
Second Failure Test
4m
Purposes: • Fail the inboard region of the blade
• Examine the failure mode
Method: • Continuously loading using 4-m crane
Results: • No failure detected up to 420% Pdextreme
• Loading aborted due to safety concern
Finite Element Analysis
Purposes: • Complement experiment to further understand structural behavior of the blade
• Providing an effective numerical model for the future parametric study.
Model Information:
• Nonlinear analysis with 24,700 shell element “s4r” in Abaqus/standard
• Fixed root boundary and distributed point loads simulating test loads
• 2D Tsai-Wu Criteria used for predicting composite failure
0.0
0.5
1.0
1.5
2.0
2.5
3.0
0 2 4 6 8 10 12
Defl
ecti
on (
m)
Blade span (m)
Test
FEA210%
180%
140%
80%
60%
40%
100%
0.00
0.05
0.10
0.15
3.9 4 4.1
-8,000
-6,000
-4,000
-2,000
0
2,000
4,000
6,000
8,000
0 1 2 3 4 5 6 7 8 9 10
Str
ain
ε1
1(μ
)
Blade span (m)
Flap_Max
系列1
Test, 220%
系列3
FEA,220%
Test, 100%
Test, 210%
-8,000
-6,000
-4,000
-2,000
0
2,000
4,000
6,000
8,000
0 1 2 3 4 5 6 7 8 9 10
Str
ain
ε1
1(μ
)
Blade span (m)
Flap_Max
系列1
Test, 220%
系列3
FEA,220%
FEA, 100%
FEA, 210%
-8,000
-6,000
-4,000
-2,000
0
2,000
4,000
6,000
8,000
0 1 2 3 4 5 6 7 8 9 10
Str
ain
ε1
1(μ
)
Blade span (m)
Flap_Max
Test_220%
系列1
FEA_220%
系列3Pressure side
Suction side
Finite Element Model Validation
Blade deflection Spar cap strain
Prediction on the 1st Failure Test
5.20 m
Spar cap
6.30 m
Fig. 15 Predicted failure at 220% test loads
4m
8m
At 220%Pdextreme
At 220%Pdextreme
4m
8m
FE Model:
Failure mode
Failure location
Prediction on the 2nd Failure Test
Spar cap
Fig. 16 Spar cap failure of inboard region at 543% test load
4m
Fig. 17 First buckling mode of inboard region at 445% test load
Buckling frequency is 4.45
4m
Linear buckling region @ 445% Pdextreme
Composite failure region @ 543% Pdextreme Failure load:
FEA: 543%, 445%
Test: at least 420%
New conceptual design of wind turbine blades were proposed by IET-Wind.
Experimental study and FE analysis were carried out on a 10.3 m prototype
blade to verify the proposed design. It was found that:
The proposed blade exhibited good buckling resistance at trailing
edge and the maximum chord panel which are usually susceptible to
local instability for the blades with conventional designs.
Root transition region exhibited high ultimate strength and survived
over 4 times of extreme design loads. Further weight reduce is
possible by material tailoring.
The blade showed a preferred failure mode of composite crushing by
which the material strength was fully utilized.
FE modeling method was proved to be efficient to capture spar cap
strains, deflection and the failure of the blade. It can be used to model
large blades with new design concepts proposed by IET-Wind.
Conclusion
The proposed blades have been
installed on a 100kW wind turbine and
the field test is currently in process in
order to study aerodynamics,
aeroelastics, aeroacoustics and
structures of the blades in the real world.
Thank you for your attention.
Future Work