scholarly journals Design and analysis of displacement models for modular horizontal wind turbine blade structure

2020 ◽  
Vol 39 (1) ◽  
pp. 121-130
Author(s):  
E.M. Etuk ◽  
A.E. Ikpe ◽  
U.A. Adoh
Keyword(s):  
Wind Turbine ◽  
Rotor Blade ◽  
Structural Damage ◽  
Axial Loading ◽  
Turbine Rotor ◽  
Rotor Blades ◽  
Horizontal Wind ◽  
Normal Loading ◽  
Loading Cycle ◽  
Wind Turbine Rotor

This study examined the normal, radial, axial and tangential loading cycles undergone by wind turbine rotor blades and their effects on the  displacement of the blade structure. The rotor blade was modelled using Q Blade finite element sub module, which evaluated the loading cycles in  terms of the forces induced on the blade at various frequencies through several complete revolution cycles (360o each cycle). At frequencies of 5 HZ, 23 Hz, 60 Hz, 124 Hz and 200 Hz, maximum strain deformation of 0.004, 0.04, 0.08, 0.14 and 0.24 were obtained, and geometry of the deformed blades were characterized by twisting and bending configuration. Maximum deflections from tangential loading increased from -0.55-1.2 mm,  -0.39-1.6 mm from axial loading, -0.28-1.8 mmfrom radial loading and -0.01-2.3 mm from normal loading. From these deflection values, normal loading cycle would cause the highest level of structural damage on the rotor blade followed by radial, axial and tangential loading. Moreover, the  strain deformations and deflections of the blade structure increased as the cycles of frequency increased. Keywords: Loading cycle, Wind turbine, Rotor blade, Frequency, Strain deformations, Deflections.

scholarly journals Full scale deformation measurements of a wind turbine rotor in comparison with aeroelastic simulations

2020 ◽  
Author(s):  
Stephanie Lehnhoff ◽  
Alejandro Gómez González ◽  
Jörg R. Seume
Keyword(s):  
Wind Turbine ◽  
Rotor Blade ◽  
Plane Deformation ◽  
Field Measurements ◽  
Turbine Rotor ◽  
Rotor Blades ◽  
Strain Gauges ◽  
Aeroelastic Simulations ◽  
Good Agreement ◽  
Wind Turbine Rotor

Abstract. The measurement of deformation and vibration of wind turbine rotor blades becomes highly important as the length of rotor blades increases with the growth in demand for wind power. The requirement for field validation of the aeroelastic behaviour of wind turbines increases with the scale of the deformation, in particular for modern blades with very high flexibility and coupling between different vibration modes. However, performing full-scale field measurements for rotor blade deformation is not trivial and requires high temporal and spatial resolution. A promising deformation measurement technique is based on an optical method called Digital Image Correlation (DIC). A system for the application of DIC for full field measurements of wind turbine rotors has been developed and validated in the past years by ForWind, Institute of Turbomachinery and Fluid Dynamics, Leibniz Universität Hannover. The whole rotor of the wind turbine is monitored with a stereo camera system from the ground during measurement. Recently, DIC measurements on a Siemens Gamesa SWT-4.0-130 test turbine were performed on the tip of all blades with synchronized measurement of the inflow conditions by a ground-based LiDAR. As the turbine was additionally equipped with strain gauges in the blade root of all blades, the DIC results can be directly compared to the actual prevailing loads. In the end, the measured deformations are compared to aeroelastic simulations. The deformation measured with DIC on the rotor blade tips shows the same qualitative behaviour when compared to loads measured with strain gauges in the blade root. This confirms that the DIC measurements correlate with the prevailing loads in reality. The comparison with aeroelastic simulations shows that the amplitude and trend of the in-plane deformation is in very good agreement with the DIC measurements. The out-of-plane deformation shows slight differences, which could be caused by the difference between real wind conditions and the wind statistics on which the simulations are based. The combined rotor blade pitch and torsion angle measured with DIC is in good agreement with the actual pitch value of the turbine. A detailed comparison with aeroelastic simulations shows that the amplitude of torsion measured with DIC is higher which might be caused by an inaccuracy of the experimental setup. This will be focus of future work. All in all, DIC shows very good agreement with comparative measurements and simulations which shows that it is a suitable method for measurements of deformation and torsion of multi-megawatt wind turbine rotor blades.

3D Woven Carbon/Glass Hybrid Spar Cap for Wind Turbine Rotor Blade

2006 ◽  
Vol 128 (4) ◽  
pp. 562-573 ◽  
Author(s):  
Mansour H. Mohamed ◽  
Kyle K. Wetzel
Keyword(s):  
Wind Turbine ◽  
Carbon Fibers ◽  
Rotor Blade ◽  
Turbine Rotor ◽  
Rotor Blades ◽  
Constant Thickness ◽  
Turbine Rotor Blade ◽  
Parametric Studies ◽  
The Impact ◽  
Wind Turbine Rotor

This paper presents the design and analysis for a spar cap for a wind turbine rotor blade. The cap is formed of an integral, unitary 3D woven material (3WEAVE®) having constant thickness; spar cap weight is varied and controlled by appropriately tapering the cap width from the blade root to tip. This analysis is employed for 24-m and 37-m rotor blades. These studies are conducted parametrically, examining a range of 3WEAVE® materials incorporating varying fractions of glass and carbon fibers, and hence exhibiting a range of structural properties and material costs. These parametric studies are used to determine the impact on blade weight and cost resulting from the various materials studied. Detailed results are presented in the form of tables to enable candidate materials to be evaluated as they are developed.

Harmonization of new wind turbine rotor blades development process: A review

2014 ◽  
Vol 39 ◽  
pp. 874-882 ◽  
Author(s):  
B. Rašuo ◽  
M. Dinulović ◽  
A. Veg ◽  
A. Grbović ◽  
A. Bengin
Keyword(s):  
Wind Turbine ◽  
Development Process ◽  
Turbine Rotor ◽  
Rotor Blades ◽  
Wind Turbine Rotor

Development of a Scaled Rotor Blade for Tank Tests of Floating Wind Turbine Systems

2018 ◽  
Author(s):  
Paul Schünemann ◽  
Timo Zwisele ◽  
Frank Adam ◽  
Uwe Ritschel
Keyword(s):  
Wind Turbine ◽  
Rotor Blade ◽  
Turbine Rotor ◽  
Full Scale ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Model Scale ◽  
Floating Wind Turbine ◽  
Hydrodynamic Effects ◽  
Wind Turbine Rotor

Floating wind turbine systems will play an important role for a sustainable energy supply in the future. The dynamic behavior of such systems is governed by strong couplings of aerodynamic, structural mechanic and hydrodynamic effects. To examine these effects scaled tank tests are an inevitable part of the design process of floating wind turbine systems. Normally Froude scaling is used in tank tests. However, using Froude scaling also for the wind turbine rotor will lead to wrong aerodynamic loads compared to the full-scale turbine. Therefore the paper provides a detailed description of designing a modified scaled rotor blade mitigating this problem. Thereby a focus is set on preserving the tip speed ratio of the full scale turbine, keeping the thrust force behavior of the full scale rotor also in model scale and additionally maintaining the power coefficient between full scale and model scale. This is achieved by completely redesigning the original blade using a different airfoil. All steps of this redesign process are explained using the example of the generic DOWEC 6MW wind turbine. Calculations of aerodynamic coefficients are done with the software tools XFoil and AirfoilPrep and the resulting thrust and power coefficients are obtained by running several simulations with the software AeroDyn.

Monitoring system of wind turbine rotor blades

2009 ◽  
Author(s):  
B. Frankenstein ◽  
L. Schubert ◽  
N. Meyendorf ◽  
H. Friedmann ◽  
C. Ebert
Keyword(s):  
Wind Turbine ◽  
Monitoring System ◽  
Turbine Rotor ◽  
Rotor Blades ◽  
Wind Turbine Rotor

Model Identification and Operating Load Characterization for a Small Horizontal Axis Wind Turbine Rotor Using Integrated Blade Sensors

2010 ◽  
Author(s):  
Scott Dana ◽  
Joseph Yutzy ◽  
Douglas E. Adams
Keyword(s):  
Dynamic Response ◽  
Wind Turbine ◽  
Rotor Blade ◽  
Model Identification ◽  
Turbine Rotor ◽  
Forced Response ◽  
Horizontal Axis ◽  
Horizontal Axis Wind Turbine ◽  
And Control ◽  
Wind Turbine Rotor

One of the primary challenges in diagnostic health monitoring and control of wind turbines is compensating for the variable nature of wind loads. Given the sometimes large variations in wind speed, direction, and other operational variables (like wind shear), this paper proposes a data-driven, online rotor model identification approach. A 2 m diameter horizontal axis wind turbine rotor is first tested using experimental modal analysis techniques. Through the use of the Complex Mode Indication Function, the dominant natural frequencies and mode shapes of dynamic response of the rotor are estimated (including repeated and pseudo-repeated roots). The free dynamic response properties of the stationary rotor are compared to the forced response of the operational rotor while it is being subjected to wind and rotordynamic loads. It is demonstrated that both narrowband (rotordynamic) and broadband (wind driven) responses are amplified near resonant frequencies of the rotor. Blade loads in the flap direction of the rotor are also estimated through matrix inversion for a simulated set of rotor blade input forces and for the operational loading state of the wind turbine in a steady state condition. The analytical estimates are shown to be accurate at frequencies for which the ordinary coherence functions are near unity. The loads in operation are shown to be largest at points mid-way along the span of the blade and on one of the three blades suggesting this method could be used for usage monitoring. Based on these results, it is proposed that a measurement of upstream wind velocity will provide enhanced models for diagnostics and control by providing a leading indicator of disturbances in the loads.

Implementation of bending-torsion coupling in the design of a wind-turbine rotor-blade

1999 ◽  
Vol 63 (3) ◽  
pp. 191-207 ◽  
Author(s):  
W.C. de Goeij ◽  
M.J.L. van Tooren ◽  
A. Beukers
Keyword(s):  
Wind Turbine ◽  
Rotor Blade ◽  
Turbine Rotor ◽  
Turbine Rotor Blade ◽  
Wind Turbine Rotor
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