Articles | Volume 1, issue 2
https://doi.org/10.5194/wes-1-271-2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
https://doi.org/10.5194/wes-1-271-2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
Modal dynamics of structures with bladed isotropic rotors and its complexity for two-bladed rotors
Dept. of Wind Energy, Technical University of Denmark, Frederiksborgvej 399, 4000 Roskilde, Denmark
Related authors
Alexander R. Stäblein, Morten H. Hansen, and David R. Verelst
Wind Energ. Sci., 2, 343–360, https://doi.org/10.5194/wes-2-343-2017, https://doi.org/10.5194/wes-2-343-2017, 2017
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Coupling between bending and twist has a significant influence on the aeroelastic response of wind turbine blades. The coupling can arise from the blade geometry or from the anisotropic properties of the blade material. Bend–twist coupling can be utilised to reduce the fatigue loads of wind turbine blades. In this study the effects of material-based coupling on the aeroelastic modal properties and stability limits of the DTU 10 MW Reference Wind Turbine are investigated.
Georg Pirrung, Vasilis Riziotis, Helge Madsen, Morten Hansen, and Taeseong Kim
Wind Energ. Sci., 2, 15–33, https://doi.org/10.5194/wes-2-15-2017, https://doi.org/10.5194/wes-2-15-2017, 2017
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The certification process of a wind turbine requires simulations of a coupled structural and aerodynamic wind turbine model in many different external conditions. Due to the large number of load cases, the complexity of the aerodynamics models has to be limited. In this paper, a simplified vortex method based aerodynamics model is described. It is shown that this model, which is fast enough for use in a certification context, can produce results similar to those of a more complex vortex model.
Alexander R. Stäblein, Morten H. Hansen, and David R. Verelst
Wind Energ. Sci., 2, 343–360, https://doi.org/10.5194/wes-2-343-2017, https://doi.org/10.5194/wes-2-343-2017, 2017
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Coupling between bending and twist has a significant influence on the aeroelastic response of wind turbine blades. The coupling can arise from the blade geometry or from the anisotropic properties of the blade material. Bend–twist coupling can be utilised to reduce the fatigue loads of wind turbine blades. In this study the effects of material-based coupling on the aeroelastic modal properties and stability limits of the DTU 10 MW Reference Wind Turbine are investigated.
Georg Pirrung, Vasilis Riziotis, Helge Madsen, Morten Hansen, and Taeseong Kim
Wind Energ. Sci., 2, 15–33, https://doi.org/10.5194/wes-2-15-2017, https://doi.org/10.5194/wes-2-15-2017, 2017
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The certification process of a wind turbine requires simulations of a coupled structural and aerodynamic wind turbine model in many different external conditions. Due to the large number of load cases, the complexity of the aerodynamics models has to be limited. In this paper, a simplified vortex method based aerodynamics model is described. It is shown that this model, which is fast enough for use in a certification context, can produce results similar to those of a more complex vortex model.
Related subject area
Material science and structural mechanics
A symbolic framework to obtain mid-fidelity models of flexible multibody systems with application to horizontal-axis wind turbines
Wind turbine main-bearing lubrication – Part 1: An introductory review of elastohydrodynamic lubrication theory
Seismic soil–structure interaction analysis of wind turbine support structures using augmented complex mode superposition response spectrum method
Model updating of a wind turbine blade finite element Timoshenko beam model with invertible neural networks
Validation of a modeling methodology for wind turbine rotor blades based on a full-scale blade test
A fracture mechanics framework for optimising design and inspection of offshore wind turbine support structures against fatigue failure
Constructing fast and representative analytical models of wind turbine main bearings
Development of a numerical model of a novel leading edge protection component for wind turbine blades
Finite element simulations for investigating the strength characteristics of a 5 m composite wind turbine blade
Simplified support structure design for multi-rotor wind turbine systems
Beamlike models for the analyses of curved, twisted and tapered horizontal-axis wind turbine (HAWT) blades undergoing large displacements
A novel rotor blade fatigue test setup with elliptical biaxial resonant excitation
The effects of blade structural model fidelity on wind turbine load analysis and computation time
A review of wind turbine main bearings: design, operation, modelling, damage mechanisms and fault detection
Determination of natural frequencies and mode shapes of a wind turbine rotor blade using Timoshenko beam elements
Remote surface damage detection on rotor blades of operating wind turbines by means of infrared thermography
Effects of moisture absorption on damage progression and strength of unidirectional and cross-ply fiberglass–epoxy composites
Benefits of subcomponent over full-scale blade testing elaborated on a trailing-edge bond line design validation
Friction torque of wind-turbine pitch bearings – comparison of experimental results with available models
Effects of defects in composite wind turbine blades – Part 1: Characterization and mechanical testing
Effects of defects in composite wind turbine blades – Part 2: Progressive damage modeling of fiberglass-reinforced epoxy composites with manufacturing-induced waves
Emmanuel Branlard and Jens Geisler
Wind Energ. Sci., 7, 2351–2371, https://doi.org/10.5194/wes-7-2351-2022, https://doi.org/10.5194/wes-7-2351-2022, 2022
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The article presents a framework to obtain the linear and nonlinear equations of motion of a multibody system including rigid and flexible bodies. The method yields compact symbolic equations of motion. The applications are many, such as time-domain simulation, stability analyses, frequency domain analyses, advanced controller design, state observers, and digital twins.
Edward Hart, Elisha de Mello, and Rob Dwyer-Joyce
Wind Energ. Sci., 7, 1021–1042, https://doi.org/10.5194/wes-7-1021-2022, https://doi.org/10.5194/wes-7-1021-2022, 2022
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This work provides an accessible introduction to elastohydrodynamic lubrication theory as a precursor to analysis of lubrication in a wind turbine main bearing. Fundamental concepts, derivations and formulas are presented, followed by the more advanced topics of starvation, non-steady effects, surface roughness interactions and grease lubrication.
Masaru Kitahara and Takeshi Ishihara
Wind Energ. Sci., 7, 1007–1020, https://doi.org/10.5194/wes-7-1007-2022, https://doi.org/10.5194/wes-7-1007-2022, 2022
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The seismic soil–structure interaction of wind turbine support structures is investigated. Wind turbine support structures are modelled as a non-classically damped system, and its seismic loadings are analytically derived by the response spectrum method. To improve the prediction accuracy of the shear force on the footing, a threshold for the allowable modal damping ratio is proposed. The proposed method is capable of effectively estimating seismic loadings on the tower and footing.
Pablo Noever-Castelos, David Melcher, and Claudio Balzani
Wind Energ. Sci., 7, 623–645, https://doi.org/10.5194/wes-7-623-2022, https://doi.org/10.5194/wes-7-623-2022, 2022
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In the wind energy industry, a digital twin is fast becoming a key instrument for the monitoring of a wind turbine blade's life cycle. Here, our introduced model updating with invertible neural networks provides an efficient and powerful technique to represent the real blade as built. This method is applied to a full finite element Timoshenko beam model of a blade to successfully update material and layup parameters. The advantage over state-of-the-art methods is the established inverse model.
Pablo Noever-Castelos, Bernd Haller, and Claudio Balzani
Wind Energ. Sci., 7, 105–127, https://doi.org/10.5194/wes-7-105-2022, https://doi.org/10.5194/wes-7-105-2022, 2022
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Modern rotor blade designs depend on detailed numerical models and simulations. Thus, a validated modeling methodology is fundamental for reliable designs. This paper briefly presents a modeling algorithm for rotor blades, its validation against real-life full-scale blade tests, and the respective test data. The hybrid 3D shell/solid finite-element model is successfully validated against the conducted classical bending tests in flapwise and lead–lag direction as well as novel torsion tests.
Peyman Amirafshari, Feargal Brennan, and Athanasios Kolios
Wind Energ. Sci., 6, 677–699, https://doi.org/10.5194/wes-6-677-2021, https://doi.org/10.5194/wes-6-677-2021, 2021
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One particular problem with structures operating in seas is the so-called fatigue phenomenon. Cyclic loads imposed by waves and winds can cause structural failure after a number of cycles. Traditional methods have some limitations.
This paper presents a developed design framework based on fracture mechanics for offshore wind turbine support structures which enables design engineers to maximise the use of available inspection capabilities and optimise the design and inspection, simultaneously.
James Stirling, Edward Hart, and Abbas Kazemi Amiri
Wind Energ. Sci., 6, 15–31, https://doi.org/10.5194/wes-6-15-2021, https://doi.org/10.5194/wes-6-15-2021, 2021
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This paper considers the modelling of wind turbine main bearings using analytical models. The validity of simplified analytical representations is explored by comparing main-bearing force reactions with those obtained from higher-fidelity 3D finite-element models. Results indicate that good agreement can be achieved between the analytical and 3D models in the case of both non-moment-reacting (such as for a spherical roller bearing) and moment-reacting (such as a tapered roller bearing) set-ups.
William Finnegan, Priya Dasan Keeryadath, Rónán Ó Coistealbha, Tomas Flanagan, Michael Flanagan, and Jamie Goggins
Wind Energ. Sci., 5, 1567–1577, https://doi.org/10.5194/wes-5-1567-2020, https://doi.org/10.5194/wes-5-1567-2020, 2020
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Leading edge erosion is an ever-existing damage issue on wind turbine blades. This paper presents the numerical finite element analysis model for incorporating a new leading edge protection component for offshore applications, which is manufactured from thermoplastic polyurethane, into wind turbine blade designs. The model has been validated against experimental trials at demonstrator level, comparing the deflection and strains during testing, and then applied to a full-scale wind turbine blade.
Can Muyan and Demirkan Coker
Wind Energ. Sci., 5, 1339–1358, https://doi.org/10.5194/wes-5-1339-2020, https://doi.org/10.5194/wes-5-1339-2020, 2020
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Wind turbine blade prototypes undergo structural tests before they are used in the field so that any design failure can be detected prior to their operation. In this study, strength characteristics of a small-scale existing 5 m composite wind turbine blade is carried out utilizing the finite-element-method software package Ansys. The results show that the blade exhibits sufficient resistance against buckling. Yet, laminate failure is found to play a major role in the ultimate blade failure.
Sven Störtenbecker, Peter Dalhoff, Mukunda Tamang, and Rudolf Anselm
Wind Energ. Sci., 5, 1121–1128, https://doi.org/10.5194/wes-5-1121-2020, https://doi.org/10.5194/wes-5-1121-2020, 2020
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Multi-rotor wind turbine systems show the potential to reduce the levelized cost of energy. In this study a simplified and fast method as a first venture to find an optimal number of rotors and design parameters is presented. A variety of space frame designs are dimensioned based on ultimate loads and buckling, as a preliminary step for later detailed analyses.
Giovanni Migliaccio, Giuseppe Ruta, Stefano Bennati, and Riccardo Barsotti
Wind Energ. Sci., 5, 685–698, https://doi.org/10.5194/wes-5-685-2020, https://doi.org/10.5194/wes-5-685-2020, 2020
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This work addresses the mechanical modelling of complex beamlike structures, which may be curved, twisted and tapered in their reference state and undergo large displacements, 3D cross-sectional warping and small strains. A model suitable for the problem at hand is proposed. It can be used to analyze large deflections under prescribed loads and determine the stress and strain fields in the structure. Analytical and numerical results obtained by applying the proposed modelling approach are shown.
David Melcher, Moritz Bätge, and Sebastian Neßlinger
Wind Energ. Sci., 5, 675–684, https://doi.org/10.5194/wes-5-675-2020, https://doi.org/10.5194/wes-5-675-2020, 2020
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When a new rotor blade is designed, a prototype needs to be qualified by testing in two separate directions before it can be used in the field. These tests are time-consuming and expensive. Combining these two tests into one by applying loads in two directions simultaneously is a possible method to reduce time and costs. This paper presents a new computational method, which is capable of designing these complex tests and shows exemplarily that the combined test is faster than traditional tests.
Ozan Gözcü and David R. Verelst
Wind Energ. Sci., 5, 503–517, https://doi.org/10.5194/wes-5-503-2020, https://doi.org/10.5194/wes-5-503-2020, 2020
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Geometrically nonlinear blade modeling effects on the turbine loads and computation time are investigated in an aero-elastic code based on multibody formulation. A large number of fatigue load cases are used in the study. The results show that the nonlinearities become prominent for large and flexible blades. It is possible to run nonlinear models without significant increase in computational time compared to the linear model by changing the matrix solver type from dense to sparse.
Edward Hart, Benjamin Clarke, Gary Nicholas, Abbas Kazemi Amiri, James Stirling, James Carroll, Rob Dwyer-Joyce, Alasdair McDonald, and Hui Long
Wind Energ. Sci., 5, 105–124, https://doi.org/10.5194/wes-5-105-2020, https://doi.org/10.5194/wes-5-105-2020, 2020
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This paper presents a review of existing theory and practice relating to main bearings for wind turbines. Topics covered include wind conditions and resulting rotor loads, main-bearing models, damage mechanisms and fault detection procedures.
Evgueni Stanoev and Sudhanva Kusuma Chandrashekhara
Wind Energ. Sci., 4, 57–69, https://doi.org/10.5194/wes-4-57-2019, https://doi.org/10.5194/wes-4-57-2019, 2019
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In the frame of a multi-body simulation of a wind turbine, the lowest rotor blade eigenmodes are used to describe their elastic deformations. In this paper, a finite Timoshenko beam element is proposed based on the transfer matrix method. The element stiffness and mass matrices are derived by numerical integration of the differential equations of motion. A numerical example with generic rotor blade data demonstrates the performance of the method in comparison with FAST/ADAMS software results.
Dominik Traphan, Iván Herráez, Peter Meinlschmidt, Friedrich Schlüter, Joachim Peinke, and Gerd Gülker
Wind Energ. Sci., 3, 639–650, https://doi.org/10.5194/wes-3-639-2018, https://doi.org/10.5194/wes-3-639-2018, 2018
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Wind turbines are exposed to harsh weather, leading to surface defects on rotor blades emerging from the first day of operation. Defects
grow quickly and affect the performance of wind turbines. Thus, there is demand for an easily applicable remote-inspection method that is sensitive to small
surface defects. In this work we show that infrared thermography can meet these requirements by visualizing differences in the surface temperature
of the rotor blades downstream of surface defects.
Jake D. Nunemaker, Michael M. Voth, David A. Miller, Daniel D. Samborsky, Paul Murdy, and Douglas S. Cairns
Wind Energ. Sci., 3, 427–438, https://doi.org/10.5194/wes-3-427-2018, https://doi.org/10.5194/wes-3-427-2018, 2018
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This paper presents an experimental investigation of the tensile strength of fiberglass–epoxy composites before and after water saturation. The strengths of [0], [90], and [0/90] layups all show a drop in tensile strength. However, investigation of the data, damaged coupons, and acoustic emission events illustrates a change in the mechanism governing final failure between the dry and saturated coupons. This illustrates the complexity of strength prediction of multiple layups after saturation.
Malo Rosemeier, Gregor Basters, and Alexandros Antoniou
Wind Energ. Sci., 3, 163–172, https://doi.org/10.5194/wes-3-163-2018, https://doi.org/10.5194/wes-3-163-2018, 2018
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This research was conducted with the help of computer models to give argumentation on how the reliability of wind turbine rotor blade structures can be increased using subcomponent testing (SCT) as a supplement to full-scale blade testing (FST). It was found that the use of SCT can significantly reduce the testing time compared to FST while replicating more realistic loading conditions for an outboard blade segment as it occurs in the field.
Matthias Stammler, Fabian Schwack, Norbert Bader, Andreas Reuter, and Gerhard Poll
Wind Energ. Sci., 3, 97–105, https://doi.org/10.5194/wes-3-97-2018, https://doi.org/10.5194/wes-3-97-2018, 2018
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Modern wind turbines all share the ability to turn (pitch) the blades around their main axis. By pitching the blades, the aerodynamic forces created by the blades are controlled. Rolling bearings, consisting of two steel rings and balls that roll on raceways between them, are used to allow pitching. To design pitch drives, it is necessary to know the losses within the bearings. This article describes how such losses have been measured and compares them with calculation models.
Jared W. Nelson, Trey W. Riddle, and Douglas S. Cairns
Wind Energ. Sci., 2, 641–652, https://doi.org/10.5194/wes-2-641-2017, https://doi.org/10.5194/wes-2-641-2017, 2017
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Given the rapid growth and large scale of wind turbines, it is important that wind farms achieve maximum availability by reducing downtime due to maintenance and failures. The Blade Reliability Collaborative, led by Sandia National Laboratories and sponsored by the US DOE, was formed to address this issue. A comprehensive study to characterize and understand the manufacturing flaws common in blades, and their impact on blade life, was performed by measuring and testing commonly included defects.
Jared W. Nelson, Trey W. Riddle, and Douglas S. Cairns
Wind Energ. Sci., 2, 653–669, https://doi.org/10.5194/wes-2-653-2017, https://doi.org/10.5194/wes-2-653-2017, 2017
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The Blade Reliability Collaborative was formed to address wind turbine blade reliability. To better understand and predict these effects, various progressive damage modeling approaches, built upon the characterization previously addressed, were investigated. The results indicate that a combined continuum–discrete approach provides insight into reliability with known defects when used in conjunction with a probabilistic flaw framework.
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Short summary
The modal dynamics of wind turbines are the fingerprints of their responses under the stochastic excitation from the wind field. Commercial wind turbines have typically three-bladed rotors, and their modal dynamics are well understood. Two-bladed turbines are still commercially less successful, and this work also shows that their modal dynamics are significantly more complex than that of turbines with three or more blades.
The modal dynamics of wind turbines are the fingerprints of their responses under the stochastic...
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