k. schröder, s. grove, s. tsiapoki, c.g. gebhardt and r ... · gebhardt and r. rolfes. eera...
TRANSCRIPT
Structural Change Identification at a Wind Turbine Blade using Model Updating
K. Schröder, S. Grove, S. Tsiapoki, C.G. Gebhardt and R. Rolfes
EERA DeepWind’18, 18.01.18
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Content
I. Motivation
II. Optimization based model updating
III. Rotor blade test
IV. Model updating at the rotor blade1. Damage localization2. Ice accretion
V. Conclusion and Outlook
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Motivation
• Remote location
• Rotor blades: costly and time-consuming repair
• Ice accretion: - Risk of ice throw
- Undesired loads
Localization and quantification of structuralchanges using model updating
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Finite Element Model Updating
Damage event
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Deviation between numerical model andmeasured data
Modal parameters
Transmissibility functions
• Eigenvalues• Mode shapes
Quantification of the „difference“ between model and measurement
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Minimization of the deviation
• Nonlinear• Constrained• Nonconvex• Several local minima
Global optimization algorithm:Simulated Quenching
Local optimization algorithm:Sequential Quadratic Programming
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Rotor blade test
• Hammer excitation
• 12 measurement channels
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• Hammer excitation
• 12 measurement channels
• Ice mass
• Damage
Trailing edge bondline: Spot of damage initiation
Trailing edge – PressureSide (outside)
Rotor blade test
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Numerical Modeling
•Rectangular Cross Section
•Known: EI and mass
•26 Timoshenko beam elements
•Clamping at blade root
•Material damping
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Numerical validation
Stiffness reduction
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Numerical validation–Modal Parameters
Parameter number
Parameter number
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Numerical validation –Transmissibility Functions
Parameter number
Parameter number
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Ice accretion
• 4 steps
• Variation of density
• Optimization problem:
• Step 3: 14,4kg at 32m-33m and 33m-34m
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Ice localization – Modal Parameters
• Correct Localizations in runs 1, 3, 7, 9 und 11
• Verification using objective function value
• Ice localization using modal parameters is possible
Parameter number
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Ice quantification – Modal ParametersSt
iffne
ssPa
ram
eter
4 in
%
Ice set (rotor blade mass in %)0.1 0.3 0.6 0.9
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Conclusion & Outlook
• Updating in numerical examplesand for ice quantification successful
• Minimization using global two-step optimization algorithm• No success for damage localization using measured data• Modal parameters superior to transmissibility functions
• Investigate more advanced metrics for model updating• Application to changing conditions (in situ)
Conclusion
Outlook
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Thank you for your attention!
Leibniz Universität HannoverInstitute of Structural Analysis (ISD)Appelstraße 9a, 30167 Hannover
+49 511 762 [email protected]