Articles | Volume 3, issue 2
13 Sep 2018
Research article | 13 Sep 2018
Remote surface damage detection on rotor blades of operating wind turbines by means of infrared thermography
Dominik Traphan et al.
No articles found.
Ingrid Neunaber, Joachim Peinke, and Martin Obligado
Wind Energ. Sci., 7, 201–219,Short summary
Wind turbines are often clustered within wind farms. A consequence is that some wind turbines may be exposed to the wakes of other turbines, which reduces their lifetime due to the wake turbulence. Knowledge of the wake is thus important, and we carried out wind tunnel experiments to investigate the wakes. We show how models that describe wakes of bluff bodies can help to improve the understanding of wind turbine wakes and wind turbine wake models, particularly by including a virtual origin.
Sirko Bartholomay, Tom T. B. Wester, Sebastian Perez-Becker, Simon Konze, Christian Menzel, Michael Hölling, Axel Spickenheuer, Joachim Peinke, Christian N. Nayeri, Christian Oliver Paschereit, and Kilian Oberleithner
Wind Energ. Sci., 6, 221–245,Short summary
This paper presents two methods on how to estimate the lift force that is created by a wing. These methods were experimentally assessed in a wind tunnel. Furthermore, an active trailing-edge flap, as seen on airplanes for example, is used to alleviate fluctuating loads that are created within the employed wind tunnel. Thereby, an active flow control device that can potentially serve on wind turbines to lower fatigue or lower the material used for the blades is examined.
Khaled Yassin, Hassan Kassem, Bernhard Stoevesandt, Thomas Klemme, and Joachim Peinke
Wind Energ. Sci. Discuss.,
Revised manuscript not acceptedShort summary
When ice forms on wind turbine blades, the smooth surface of the blade becomes rough which changes its aerodynamic performance. So, it is very important to know how to simulate this rough surface since most CFD simulations depend on assuming a smooth surface. This article compares different mathematical models specialized in simulating rough surfaces with results of real ice profiles. The study presents the most accurate model and recommends using it in future airflow simulation of iced blades.
Christian Behnken, Matthias Wächter, and Joachim Peinke
Wind Energ. Sci., 5, 1211–1223,Short summary
We extend the common characterisation and modelling of wind time series with respect to higher-order statistics. We present an approach which enables us to obtain the general multipoint statistics of wind time series measured. This work is an important step in a more comprehensive description of wind also including extreme events. Important is that we show how stochastic equations can be derived from measured wind data which can be used to model long time series.
Franz Mühle, Jannik Schottler, Jan Bartl, Romain Futrzynski, Steve Evans, Luca Bernini, Paolo Schito, Martín Draper, Andrés Guggeri, Elektra Kleusberg, Dan S. Henningson, Michael Hölling, Joachim Peinke, Muyiwa S. Adaramola, and Lars Sætran
Wind Energ. Sci., 3, 883–903,
Jan Bartl, Franz Mühle, Jannik Schottler, Lars Sætran, Joachim Peinke, Muyiwa Adaramola, and Michael Hölling
Wind Energ. Sci., 3, 329–343,Short summary
Wake steering by yawing a wind turbine offers great potential to increase the wind farm power production. A model scale experiment in a controlled wind tunnel environment has been performed to map the wake flow's complex velocity distribution for different inflow conditions. A non-uniform sheared inflow was observed to affect the wake flow only insignificantly. The level of turbulent velocity fluctuations in the inflow, however, influenced the wake's velocity distribution to a higher degree.
Jannik Schottler, Jan Bartl, Franz Mühle, Lars Sætran, Joachim Peinke, and Michael Hölling
Wind Energ. Sci., 3, 257–273,Short summary
In this work, the wake flows behind two different model wind turbines were investigated in wind tunnel experiments user laser Doppler anemometry. It was found that the width of the wake flow is significantly dependent on the quantities examined, becoming much wider when taking higher-order statistics into account. This effect is stable against yaw misalignment and thus affects not only wind farm layout optimizations but also the applicability of active wake steering methods.
Iván Herráez, Elia Daniele, and J. Gerard Schepers
Wind Energ. Sci., 3, 1–9,Short summary
Several methods have been proposed in the past for extracting the blade performance of wind turbines from simulations. In this work, we present a new method that allows obtaining those data easily not only from simulation results but also from flow measurements. We apply the method to both experiments and simulations of a well-known wind turbine model. The results provide insight into the wind turbine aerodynamics and open up new possibilities for the validation of simulation models.
Jannik Schottler, Agnieszka Hölling, Joachim Peinke, and Michael Hölling
Wind Energ. Sci., 2, 439–442,Short summary
Recently, the concept of intentional derating of single wind turbines in order to increase the energy yield of a wind farm has been studied intensively. Although the potential seems promising, the effects of atmospheric conditions need to be understood in greater detail. This study shows a strong influence of vertical velocity gradients on the power output of two model wind turbines, whereas the upstream turbine is derated by an intentional misalignment of the rotor and the inflow.
Jannik Schottler, Nico Reinke, Agnieszka Hölling, Jonathan Whale, Joachim Peinke, and Michael Hölling
Wind Energ. Sci., 2, 1–13,Short summary
To what extent turbulence characteristics of wind in the atmosphere transfer to wind turbines in terms of power, loads, etc. is of great interest throughout the research community. An experimental approach using a model wind turbine at laboratory scale was used in a wind tunnel study. It is shown that the gustiness of the wind remains present in the wind turbine data, stressing the importance of including those wind characteristics in industry standards and when designing wind turbines.
David Bastine, Lukas Vollmer, Matthias Wächter, and Joachim Peinke
Wind Energ. Sci. Discuss.,
Revised manuscript not acceptedShort summary
Modeling of wind turbine wakes plays a key role in the maximization of the power output and lifetime of wind turbines in wind farms. In order to capture important dynamic and turbulent aspects of the wake, a new stochastic modeling approach is presented in this work. The resulting new kind of stochastic wake model captures important characteristics of loads which act on wind turbines in the wake. It might therefore be of great use for the planing and controlling of wind farms.
Iván Herráez, Buşra Akay, Gerard J. W. van Bussel, Joachim Peinke, and Bernhard Stoevesandt
Wind Energ. Sci., 1, 89–100,Short summary
The flow in the blade root region of horizontal axis wind turbines is highly three-dimensional. Furthermore, it is influenced by the presence of strong trailing vortices. In this work we study the complex root flow by means of experiments and numerical simulations. The simulations are shown to be reliable at predicting the main flow features of the rotor blades. Additionally, new insight into the physical mechanisms governing the blade root aerodynamics is given.
G. A. M. van Kuik, J. Peinke, R. Nijssen, D. Lekou, J. Mann, J. N. Sørensen, C. Ferreira, J. W. van Wingerden, D. Schlipf, P. Gebraad, H. Polinder, A. Abrahamsen, G. J. W. van Bussel, J. D. Sørensen, P. Tavner, C. L. Bottasso, M. Muskulus, D. Matha, H. J. Lindeboom, S. Degraer, O. Kramer, S. Lehnhoff, M. Sonnenschein, P. E. Sørensen, R. W. Künneke, P. E. Morthorst, and K. Skytte
Wind Energ. Sci., 1, 1–39,
Related subject area
Material science and structural mechanicsModel updating of a wind turbine blade finite element Timoshenko beam model with invertible neural networksValidation of a modeling methodology for wind turbine rotor blades based on a full-scale blade testSeismic soil-structure interaction analysis of wind turbine support structures using augmented complex mode superposition response spectrum methodA fracture mechanics framework for optimising design and inspection of offshore wind turbine support structures against fatigue failureConstructing fast and representative analytical models of wind turbine main bearingsDevelopment of a numerical model of a novel leading edge protection component for wind turbine bladesFinite element simulations for investigating the strength characteristics of a 5 m composite wind turbine bladeSimplified support structure design for multi-rotor wind turbine systemsBeamlike models for the analyses of curved, twisted and tapered horizontal-axis wind turbine (HAWT) blades undergoing large displacementsA novel rotor blade fatigue test setup with elliptical biaxial resonant excitationThe effects of blade structural model fidelity on wind turbine load analysis and computation timeA review of wind turbine main bearings: design, operation, modelling, damage mechanisms and fault detectionDetermination of natural frequencies and mode shapes of a wind turbine rotor blade using Timoshenko beam elementsEffects of moisture absorption on damage progression and strength of unidirectional and cross-ply fiberglass–epoxy compositesBenefits of subcomponent over full-scale blade testing elaborated on a trailing-edge bond line design validationFriction torque of wind-turbine pitch bearings – comparison of experimental results with available modelsEffects of defects in composite wind turbine blades – Part 1: Characterization and mechanical testingEffects of defects in composite wind turbine blades – Part 2: Progressive damage modeling of fiberglass-reinforced epoxy composites with manufacturing-induced wavesModal dynamics of structures with bladed isotropic rotors and its complexity for two-bladed rotors
Pablo Noever-Castelos, David Melcher, and Claudio Balzani
Wind Energ. Sci., 7, 623–645,Short summary
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,Short summary
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.
Masaru Kitahara and Takeshi Ishihara
Wind Energ. Sci. Discuss.,
Revised manuscript under review for WESShort summary
The seismic soil-structure interaction of wind turbine support structures is investigated. Wind turbine support structures are modeled by the sway-rocking model and its seismic loadings are analytically derived by complex response spectrum method. To improve the prediction accuracy of the shcar force on footings, an upper limit of modal damping ratios is proposed. The proposed method is demonstrated to be capable to accurately and efficiently estimate the seismic loadings on towers and footings.
Peyman Amirafshari, Feargal Brennan, and Athanasios Kolios
Wind Energ. Sci., 6, 677–699,Short summary
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,Short summary
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,Short summary
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,Short summary
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,Short summary
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,Short summary
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,Short summary
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,Short summary
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,Short summary
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,Short summary
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.
Jake D. Nunemaker, Michael M. Voth, David A. Miller, Daniel D. Samborsky, Paul Murdy, and Douglas S. Cairns
Wind Energ. Sci., 3, 427–438,Short summary
This paper presents an experimental investigation of the tensile strength of fiberglass–epoxy composites before and after water saturation. The strengths of , , 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,Short summary
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,Short summary
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,Short summary
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,Short summary
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.
Morten Hartvig Hansen
Wind Energ. Sci., 1, 271–296,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.
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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.
Wind turbines are exposed to harsh weather, leading to surface defects on rotor blades emerging...