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The wind energy sector is experiencing rapid growth, marked by the expansion of wind farms and the development of large-scale turbines. However, conventional manual methods for wind turbine operations and maintenance are struggling to keep pace with this development, encountering challenges related to quality, efficiency, and safety. In response, unmanned aerial vehicles (UAVs) have emerged as a promising technology offering capabilities to effectively and economically perform these tasks. This paper provides a review of state-of-the-art research and applications of UAVs in wind turbine blade damage detection, operations, and maintenance. It encompasses various topics, such as optical and thermal UAV image-based inspections, integration with robots or embedded systems for damage detection, and the design of autonomous UAV flight planning. By synthesizing existing knowledge and identifying key areas for future research, this review aims to contribute insights for advancing the digitalization and intelligence of wind energy operations.

The wind energy sector faces a persistent challenge in developing sustainable solutions for decommissioned Wind Turbine Blades (WTB). This study utilises Lifecycle Assessment (LCA) to evaluate the gate-to-gate carbon footprint of high-profile disposal and recycling methods, aiming to determine optimal strategies for WTB waste treatment in the UK. While this article analyses the UK as a case study, the findings are applicable to, and intended to inform, recycling strategies for WTB waste globally. Long-term sustainability depends heavily on factors like evolving energy grids and changing WTB waste compositions and these must be considered for robust analysis and development strategy recommendations. In the short to medium term, mechanical recycling of mixed WTB waste is sufficient to minimise Global Warming Potential (GWP) due to the scarcity of carbon fibre in WTB waste streams. Beyond 2040, carbon fibre recycling becomes crucial to reduce GWP. The study emphasises the importance of matching WTB sub-structure material compositions with preferred waste treatment options for the lowest overall impact. Future development should focus on the extraction of carbon fibre reinforced polymer (CFRP) structures in WTB waste streams, commercialising large-scale CFRP structure recycling technologies, establishing supply chains, and validating market routes for secondary carbon fibre products. In parallel, scaling up low-impact options, like mechanical recycling, is vital to minimise WTB waste landfilling. Developing viable applications and cost-effective market routes for mechanical recyclates is necessary to displace virgin glass fibres, while optimising upstream recycling processes based on product requirements.

In this paper, a new concept of extra-durable and sustainable wind turbine blades is presented. The two critical materials science challenges of the development of wind energy now are the necessity to prevent the degradation of wind turbine blades for several decades, and, on the other side, to provide a solution for the recyclability and sustainability of blades. In preliminary studies by DTU Wind, it was demonstrated that practically all typical wind turbine blade degradation mechanisms (e.g., coating detachment, buckling, spar cap/shell adhesive joint degradation, trailing edge failure, etc.) have their roots in interface degradation. The concept presented in this work includes the development of bio-inspired dual-mechanism-based interface adhesives (combining mechanical interlocking of fibers and chemical adhesion), which ensures, on the one side, extra-strong attachment during the operation time, and on the other side, possible adhesive joint separation for re-use of the blade parts. The general approach and physical mechanisms of adhesive strengthening and separation are described. [ABSTRACT FROM AUTHOR]

To meet the monitoring requirements for a certain type of tower-mounted wind turbine blade， a structural monitoring method based on a fiber Bragg grating （FBG） sensing network is proposed. A threedimensional model of the blade is established and finite element simulation is conducted to obtain the strain distribution under operational conditions. The design of FBG packaging and layout scheme enables real-time monitoring of strain values and their variations at each sensing point. Through fast Fourier transform analysis of the vibration characteristics， the influence of environmental factors such as temperature and wind speed on the reliability of the monitoring system is investigated. The results indicate that the strain-vibration testing method based on FBG can effectively monitor the blade’s response to wind pressure and vibration frequency， with an error range within 0.04 Hz， thus meeting the requirements for practical engineering applications. [ABSTRACT FROM AUTHOR]

Usually, only one surface or one side of 3D structures is measured in Scanning Laser Doppler Vibrometer (SLDV) tests due to test setup and instrumentation limitations. However, in this work, we demonstrate an approach to overcome these limitations while also using an SLDV that provides high spatial resolution measurement. In the case of a wind turbine blade, only one surface is typically measured. In most scenarios, only focusing on one surface of the blade is sufficient to characterize the dynamics of the global blade modes. However, as we show measurement of both surfaces offers valuable insights to explore both the global blade modes and the relative motions of the two surfaces of the blade. This work proposes and applies a new method of experimental modal testing on both surfaces of the wind turbine blade using a high spatial resolution 3D SLDV. The two surfaces of the wind turbine blade are scanned by the 3D SLDV respectively under the same global test coordinate system defined by several alignment objects. Then the two surfaces are stitched together to build the blade mode shapes of both surfaces. In the current testing, a total of over 1,500 points (4,500 response degrees of freedom for the 3D measurement) are scanned from both surfaces of the blade in a non-contact fashion to obtain the flap-wise, edge-wise, and torsional mode shapes of the blade. The orthogonality of the measured mode shapes, either one surface or both surfaces, is validated by the correlation tool, Modal Assurance Criterion (MAC). The effectiveness of the two-surface measurement is demonstrated by comparing the drive point Frequency Response Function and by correlating the mode shapes from the two surfaces. With the high spatial resolution 3D SLDV measurement, local panel modes of the wind turbine blade are observed from the mode shapes. Especially the panel breathing mode can only be revealed due to the two-surface measurement. This work also provides a useful reference for the wind turbine blade designers and researchers for design, structural analysis, and reliability study on the wind turbine blade. The two-surface measurement technique proposed in this work is demonstrated on a wind turbine blade, and it will also be applicable for other types of two-surface shell-type structures. [ABSTRACT FROM AUTHOR]

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To alleviate the environmental pollution caused by waste wind turbine blades and provide new ideas for recycling, the thermochemical characteristics of four basic components of composite materials commonly used in wind turbine blades were studied in this paper. Thermogravimetric experiments in different atmospheres and heating rates, and thermogravimetric‐infrared combined experiments were carried out. The results show that the reaction of epoxy resin and thermoplastic polyurethane was easy and deep in N2 and CO2. Except for glass fiber, the other three components showed different combustion characteristics in air. The maximum reaction rates and activation energy of resin‐based components in N2 increased with increasing heating rate. The pyrolysis products of the four basic components all contained CO2 and CO, and some aromatic substances could be generated during the thermal transformation of epoxy resin and thermoplastic polyurethane. It can be concluded that the thermal transformation properties of the basic components of the composite material of wind turbine blades can be used to treat the waste blades, making the resin as the matrix material undergo a thermal transformation reaction and recover the fiber. This is to effectively guarantee the green and sustainable development of wind power generation. [ABSTRACT FROM AUTHOR]

The utilization of wind power has increased almost exponentially during the last decade, leading to the growth in both the number and size of wind turbines. Modern turbine blades are typically made of fiberglass sandwiched around a balsa wood (BW) core. With an increase in the use of wind energy a collateral issue of what to do with the large and voluminous wind turbine blades (WTB) that reached end-of-life has arisen. Through previous research, we developed a recycling process that will keep these turbine blades out of the landfill by considering recycled wind turbine blades as a feedstock for second generation composite panels. The objective of this research is to further the research by understanding the effect that different compositions of wood and fiberglass have on the properties of these panels. Through testing, it was found that the addition of balsa wood increases the modulus of rupture (MOR) and the modulus of elasticity (MOE). The internal bonding (IB) strength values are well above that of typical particle board. All panels tested were visibly more resistant to water sorption than typical particle board. The thermal conductivity for all samples was within the typical range for particleboard. Fire test result indicates that the addition of balsa wood increases the heat and visible smoke release rate of composites. [ABSTRACT FROM AUTHOR]

Featured Application: The vibro-acoustic modulation (VAM) method used to detect the defect in wind turbine (WT) blades can be integrated into the currently used structural health monitoring (SHM) system. This integration does not necessitate additional hardware, and it can utilize signal-processing algorithms to extract the non-linear effects described in this paper. Wind turbines (WT) are a popular method used in energy production, but blade failure and maintenance costs pose significant challenges for the industry. Early detection of blade defects is vital to prevent collapse. This paper examines the modulation of blade vibrations via low-frequency blade rotation, mirroring the vibro-acoustic modulation (VAM) method. Specifically, we study the modulation of blade vibrations, which are generated via blade interactions with air turbulence and have a wide frequency range. These vibrations are modulated by the alternating bending stress experienced during blade rotation. For the simulation of VAM, we employ a simple breathing crack model, which considers a mechanical oscillator with parameters that are periodically changed in response to low-frequency blade rotation. The modulation of the wideband signal by blade rotation can be extracted using the detection of envelope modulation on noise (DEMON) algorithm. This model was applied for the estimation of the modulation of a large (52-m-long) WT blade. Steel specimens have been used in laboratory experiments to demonstrate the feasibility of VAM using a probe broadband noise signal. This paper presents the first work to experimentally and theoretically apply wideband signals in VAM. It further explores the analysis of the use of natural vibrations within VAM for the SHM of WT blades. [ABSTRACT FROM AUTHOR]

Biaxial fatigue testing is an effective way to verify the performance of large wind turbine blades. The test process will generate a large amount of transient strain data, which needs to be peak detection to control the loading system and provided it to third-party organizations for type certification. Peak detection is challenging due to the long test cycle and severe signal noise pollution. The objective of this article is to propose a strain data processing method based on morphological filtering. It is found that morphological filtering + three-point smoothing has a better filtering effect. In addition, a peak detection algorithm is designed and proved its effectiveness. In order to validate the proposed method, a principle prototype of biaxial fatigue testing is built for testing. The results show that the method can not only effectively filter out noise, but also accurately and quickly detect the strain peaks, improve the efficiency of damage calculation and effectively control the test process. The method can also be used in the practical engineering field to process strain data generated during fatigue testing of wind turbine blades and improve overall testing efficiency. [ABSTRACT FROM AUTHOR]

Blade icing seriously affects wind turbines' aerodynamic performance and output power. Timely and accurately predicting blade icing status is crucial to improving the economy and safety of wind farms. However, existing blade icing prediction methods cannot effectively solve the problems of unbalanced icing/non-icing data and low prediction accuracy. In order to solve the above problems, this paper proposes a wind turbine blade icing prediction method based on the focal loss function and CNN-Attention-GRU. First, the recursive feature elimination method combined with the physical mechanism of icing is used to extract features highly correlated with blade icing, and a new feature subset is formed through a sliding window algorithm. Then, the focal loss function is utilized to assign more weight to the ice samples with a lower proportion, addressing the significant class imbalance between the ice and non-ice categories. Finally, based on the CNN-Attention-GRU algorithm, a blade icing prediction model is established using continuous 24-h historical data as the input and the icing status of the next 24 h as the output. The model is compared with advanced neural network models. The results show that the proposed method improves the prediction accuracy and F1 score by an average of 6.41% and 4.27%, respectively, demonstrating the accuracy and effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

Wind turbine design and operation will benefit from a better understanding of blade dynamics. Usually, only one surface or one side of a 3D structure is measured in Scanning Laser Doppler Vibrometer (SLDV) tests due to test setup and instrumentation limitations. However, in this work, we demonstrate an approach to overcome these limitations while also using an SLDV that provides high spatial resolution measurement. In the case of a wind turbine blade, only one surface is typically measured; however, it is beneficial to investigate both blade global modes and the relative motions of the two blade surfaces by using both numerical models and experimental tests. This work creatively develops both experimental and numerical approaches to investigate the dynamics and the relative motions of both surfaces of the wind turbine blade from global and local perspectives. On the experimental side, experimental modal testing is conducted on both surfaces of the wind turbine blade with a high spatial resolution 3D SLDV. The two surfaces of the wind turbine blade are measured and stitched together to build the blade experimental mode shapes of both surfaces. A total of over 1500 points are scanned from both surfaces of the blade in a non-contact fashion to obtain not only the global bending modes (flap-wise and edge-wise), the global torsional modes, but also the localized panel mode shapes. On the numerical side, a finite element model of the blade is developed to obtain the numerical mode shapes. The experimental mode shapes on either one surface or both surfaces of the blade are used to validate the blade finite element model. The mode shape correspondence between the model and the test is also identified. With the availability of both experimental and numerical mode shapes, localized panel modes of the wind turbine blade are observed and characterized, and as a result the numerical model is validated. This work provides useful case studies for the design and structural analysis of wind turbine blades based on both the experimental observations and the validation of numerical models typical of those used for blade design and blade structural analysis. [ABSTRACT FROM AUTHOR]

Copyright of Advances in New & Renewable Energy is the property of Editorial Office of Advances in New & Renewable Energy and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this article, the sensitivity coefficients of dynamic characteristic damage identification of blades with different sizes were investigated. The results show that the first third-order vibration modes of the blade before and after damage are consistent, and the wind turbine blade size has no significant effect on the vibration mode; with the increase of the blade size, the first-, third- and fourth-order natural frequency sensitivity coefficients decrease gradually, while the second-, fifth- and sixth-order natural frequency sensitivity coefficients increase gradually; as the blade size increases, the third-order displacement mode sensitivity coefficient of the blade gradually increases, which indicates that the displacement modes identification effect is better with the increase of the blade size. With the increase of the blade size, the first- and third-order strain modal sensitivity coefficients increase gradually, which indicates that when using first- and third-order strain modes for damage identification, the larger the blade size, the better the identification effect; with the increase of the blade size, the second-order strain modal sensitivity coefficient decreases gradually, which indicates that when using second-order strain mode for damage identification, the larger the blade size, the worse the identification effect. This research could provide a theoretical basis for the application of the dynamic characteristic damage identification method in the damage identification of wind turbine blades of different sizes.

A compromise approach between aerodynamic performance and structural robustness is presented. The modeling of horizontal axis wind turbine blade GE1.5-XLE is studied regarding the applicability of three different solution methods computational fluid dynamics (CFD), one – way (unidirectional), and two – way (bidirectional) coupling fluid – structure interaction (FSI) at a shedding frequency of the vortex far from the natural frequency. The predicted results showed significant differences between the unidirectional coupling solution and experimental data. While, the bidirectional coupling method proposed accurate FSI and gave results closer to the experimental measurements than unidirectional simulation results. The bidirectional coupled approach appears to be more stable and accurate, where a large number of time steps should be used for uncoupled method to achieve the same level of precision. For the present case involving large blade strain, the difference between the prediction of rigid blade solution using CFD and FSI model increases considerably. However, it is concluded that for large blade strains, the FSI model is closer shown to be more adequate for accurate representation of the turbine performance. Moreover, when optimization is a key aspect, bidirectional simulations should be performed regardless of the higher computational cost.

Abstract A numerical analysis method of trailing edge deboning is proposed in this paper. Using this method, multiple repair parameters can be quantified by analyzing aerodynamic responses and structural characteristics of the trailing edge. This method can be applied to three types of trailing edge, including blunt trailing edge, transitional trailing edge, and pointed trailing edge. In this study, the repair parameters are divided into two types, including the internal parameters that can affect the bonding strength and the external parameters that can affect the stiffness and aerodynamic shape. The main research steps are as follows: First, a repair structure shell‐body model was developed. Second, static tensile tests were carried out using 49 specimens, covering two lap joint types and seven bonding thicknesses. Finally, nine different repaired trailing edge models were developed using Ansys/Fluent for each two two‐dimensional airfoil. A 30–40 m section of a 71 m blade was used to develop a three‐dimensional (3D) rotating model with the repaired trailing edge. The simulation results show that the two internal parameters, overlap length and the slope of adhesive joints, are the key to improving the bonding performance of the pointed trailing edge. In addition, the bonding thickness range of 1–10 mm is proved by the experiment results and numerical analysis to be sufficient for good bonding performance. Besides this, the influence of the repair height on the aerodynamic pressure distribution and lift coefficient is much greater than the repair width, and the torque and power of the repaired 3D blade model are 1.91% higher than that of the original blade. This should further help provide an effective theoretical basis for determining the repair plan for a wind turbine blade.

In this study, airfoil shape optimization of a wind turbine blade is performed using the ANSYS Fluent Adjoint Solver. The aim of this optimization process is to increase the wind turbine output power, and the objective function is to maximize the airfoil lift to drag ratio (Cl/CD ). This study is applied to the NREL phase VI wind turbine, therefore, the S809 airfoil is used as a reference profile. First, for the validation of the applied numerical model, steady-state simulations are carried out for the S809 airfoil at various angles of attack. Then, the optimization is performed with the airfoil set at a fixed angle of attack, , considering three Reynolds numbers, Re =3 105,4.8 105 and 106. Next, computations are performed for the fluid flow around the optimized airfoils at angles of attack AOA= 6.1° ranging from 0° to 20°. The results show that (i) the lift to drag ratios of the optimized airfoils are significantly improved compared to the baseline S809 airfoil, (ii) this improvement is sensitive to the Reynolds number, and (iii) the Cl/CD ratios are also improved for another angle of attack values. Thereafter, the optimized airfoils are used for the design of the NREL Phase VI blade and the aerodynamic performances of this new wind turbine are assessed using the open-source code QBlade. These latter results indicate that when the blades are designed with the optimized airfoils, the wind turbine aerodynamic performances increase significantly. Indeed, at a wind speed of 10 m/s, the power output of the wind turbine is improved by about 38% compared to that of the original turbine.

In order to research the influence of the web deflection on the bend-twist coupling characteristics of large wind turbine blades, the CAD model of NREL 5 MW blade is established based on NX secondary development, the aerodynamic loads of the blade are obtained by CFD method, the blade bendind angle and twisting angle are solved by the node displacement method to analyze the influence of web deflection for bend-twist coupling blade. The results show that the offset web helps to achieve the bend-twist coupling of blades. Under the action of aerodynamic load, the bending and twisting angle both increase along spanwise direction of blade gradually, and reach the magnitude at the tip of the blade; in forward bias, negative correlation between twist angle and offset, reverse bias is the opposite; positive bias blades bend-twist coupling coefficient is decreasing trend with the increase of deflection angle, reverse bias blade are greater than the conventional blade.

The land needed to install wind turbines is shrinking as power generation from renewable energy sources increases significantly. A large number of studies are being conducted to maximize the power extraction from wind turbines in areas with low wind speeds. Wind turbine blades play a significant role in utilizing the maximum amount of energy from the wind. The aerodynamic performance of a wind turbine blade depends on the airfoil shape. The shape optimization of an asymmetric S2027 airfoil for a low wind speed region was investigated using the adjoint-based optimization technique. The primary objectives of this study were to maximize the lift coefficient, minimize the drag coefficient, and maximize the lift-to-drag ratio. The optimization is based on the adjoint method for Reynolds number variation in the range of 2 × 105 to 5 × 105 and an angle of attack variation from 0° to 12°. A two-dimensional Reynolds–Averaged Navier–Strokes Computational Fluid Dynamics model was created with all the operating parameters and used for optimization. The aerodynamic performance was validated experimentally. For each optimization function, approximately 16 shapes were obtained. The aerodynamic performance for each optimized shape was determined under different operating conditions. Different airfoil shapes with a specific chord, leading and trailing edges, and span arrangement was obtained. The drag coefficient was reduced by 2%–30%; the lift coefficient was improved by 2%–35%, and the lift-to-drag ratio was improved up to 40%.

The utilization of biological resources is conducive to alleviating energy shortages and environmental pollution, and the application of biochar to anti-icing can promote green low-carbon cycle development. In this study, the ice-phobic coating with a photothermal effect was prepared from biogas residue after anaerobic digestion. The modification and Fe 3 O 4 loading promoted the formation of the rough structure of the material and reduced the hydrophilic groups, thus increasing the contact angle of the prepared photothermal coating to 154.49°. The rough structure of the biochar-based photothermal superhydrophobic coating effectively decreased the contact area between the coating and the ice, significantly reducing the icing adhesion strength to 71.96 kPa. The Fe 3 O 4 -loaded biochar material had an extremely high light absorption capacity, which rapidly increased the surface temperature of the coating to 48.2 °C. This was attributed to the photothermal properties of the Fe 3 O 4 particles, which enhanced the photothermal conversion performance of the photothermal coating. Icing wind tunnel experiments showed that the maximum reduction in icing mass and icing area of coated blades were 39.13% and 13.48%, respectively, compared to uncoated blades, indicating that the coating had a good anti-icing effect. The biochar-based ice-phobic coating had fine acid and alkali resistance and durability. This study provided a method for anti-icing civil and industrial material surfaces. [Display omitted] [ABSTRACT FROM AUTHOR]

The wind turbine blade trailing edge (TE) is frequently exposed to compressive loading and can even be damaged under complex operating conditions. Among the most typical TE failure modes is the adhesive-joint failure, so it is necessary to evaluate the structural behavior of the adhesive joints in TE under compressive loading. In this regard, an improved testing method was proposed for blade subcomponents. Specifically, the experiment was performed on a composite TE structural specimen under compressive loading to reveal its internal failure mechanism. The results showed that when the TE specimen was compressed under increasing load, buckling deformation occurred gradually at the sandwich laminates. Also, the bending deformations of the laminates on the suction and pressure sides were different in the bonding region. The resultant shearing effect led to the structural adhesive undergoing brittle fracture, which then triggered debonding and extension, finally causing the debonding failure of the trailing-edge specimen. To guarantee the safety of a blade under edge-wise loading, it is suggested that the structural strength of the TE should be emphasized during the blade design process. [ABSTRACT FROM AUTHOR]

Horizontal-axis wind turbines are the most popular wind machines in operation today. These turbines employ aerodynamic blades that may be oriented either upward or downward. HAWTs are the most common non-conventional source of energy generation. These turbine blades fail mostly due to fatigue, as a large centrifugal force acts on them at high rotational speeds. This study aims to increase a turbine's service life by improving the turbine blades' fatigue life. Predicting the fatigue life and the design of the turbine blade considers the maximum wind speed range. SolidWorks, a CAD program, is used to create a wind turbine blade utilizing NACA profile S814. The wind turbine blade's fatigue life is calculated using Morrow's equation. A turbine blade will eventually wear out due to several forces operating on it. Ansys software is used to analyze these stresses using the finite element method. The fatigue study of wind turbine blades is described in this research paper. To increase a turbine blade's fatigue life, this research study focuses on design optimization. Based on the foregoing characteristics, an improved turbine blade design with a longer fatigue life than the original one is intended in this study. The primary fatigue parameters are the length of a chord twist angle and blade length. The experimental data computed with the aid of a fatigue testing machine are also used to validate the numerical results, and it is found that they are very similar to one another. By creating the most effective turbine blades with the longest fatigue life, this research study can be developed further. The most effective turbine blades with the longest fatigue life can be designed to further this research investigation. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Mechanical Strength / Jixie Qiangdu is the property of Zhengzhou Research Institute of Mechanical Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Magatama type blade configuration, which has been exclusively designed for vertical axis wind turbine (VAWT), is improved by Reinforcement Learning (RL). In this RL, VAWT blade configuration that generates larger aerodynamic force in direction of rotor rotation is developed. Power performances of the VAWT with the improved new Magatama type blades are tested by wind tunnel experiments. Results show the power from the VAWT rotor with the new Magatama blades is increased. Flow structure around the new Magatama blades in the VAWT rotor and aerodynamic forces generated by the blades are investigated by unsteady numerical simulation. Results show the new blades increase rotational force in downwind zone. In this downwind zone, direction of aerodynamic force is close to that of rotor rotation. [ABSTRACT FROM AUTHOR]

Copyright of Przegląd Elektrotechniczny is the property of Przeglad Elektrotechniczny and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Advances in New & Renewable Energy is the property of Editorial Office of Advances in New & Renewable Energy and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

With the increasing installed capacity of wind turbines, ensuring the safe operation of wind turbines is of great significance. However, the failure of wind turbines is still a severe problem, especially as blade damage can cause serious harm. To detect blade damage in time and prevent the accumulation of microdamage of blades evolving into severe injury, a damage dataset based on GH Bladed simulation of blade damage is proposed. Then, based on the wavelet packet analysis theory method, the MATLAB software can automatically analyze and extract the energy characteristics of the signal to identify the damage. Finally, the GH Bladed simulation software and MATLAB software are combined for fault diagnosis analysis. The results show that the proposed method based on GH Bladed to simulate blade damage and wavelet packet analysis can extract damage characteristics and identify single-unit damage, multiple-unit damage, and different degrees of damage. This method can quickly and effectively judge the damage to wind turbine blades; it provides a basis for further research on wind turbine blade damage fault diagnosis. [ABSTRACT FROM AUTHOR]

To improve the quality and efficiency of robot grinding, a design and a control algorithm for a robot used for grinding the surfaces of large, curved workpieces with unknown parameters, such as wind turbine blades, are proposed herein. Firstly, the structure and motion mode of the grinding robot are determined. Secondly, in order to solve the problem of complexity and poor adaptability of the algorithm in the grinding process, a force/position hybrid control strategy based on fuzzy PID is proposed which greatly improves the response speed and reduces the error of the static control strategy. Compared with normal PID, fuzzy PID has the advantages of variable parameters and strong adaptability; the hydraulic cylinder used to adjust the angle of the manipulator can control the speed offset within 0.27 rad/s, and the grinding process can be carried out directly without obtaining the specific model of the surface to be machined. Finally, the experiments are carried out, the grinding force and feed speed are maintained within the allowable error range of the expected value, and the results verify the feasibility and effectiveness of the position tracking and constant force control strategy in this paper. The surface roughness of the blade is maintained within Ra = 2~3 μm after grinding, which proves that the grinding quality meets the requirements of the best surface roughness required for the subsequent process. [ABSTRACT FROM AUTHOR]

The present paper addresses some recent lightning measurements with the in actual wind turbines, to demonstrate the amount of data that is currently collected, and the information provided. Basic statistical analysis is conducted on the 2603 lightning waveforms obtained, and implications for design and verification processes for blades are suggested. Some reflections on the increased industry openness are shared, which is already benefitting the general understanding of lightning exposure, and the future standards on the topic. [ABSTRACT FROM AUTHOR]

Icing is a common phenomenon in nature and has a serious impact on wind turbines. Anti-icing coatings have become a major focus of industrial applications and academic research. In this study, a hydrophobic nano-carbon coating was prepared from corn-straw-biogas residue. The characterization results of the SEM, BET, FTIR, and XRD analyses showed that the hydrophobic nano-carbon has good pore structure and crystal structure. The hydrophobic and anti-icing effects of the carbon were confirmed by contact-angle measurements and anti-icing experiments. The ice thicknesses of the hydrophobic nano-carbon-coated aluminum-alloy blade (AAB) and bakelite blade (BB) were found to decrease by 1.20 mm and 1.10 mm, respectively, compared with those without coating; their weights decreased by 2.00 g and 1.31 g, respectively. The ratios of the icing areas before and after the hydrophobic nano-carbon coating of the AAB and BB were 8.15% and 9.65%, respectively. In brief, this method is a more effective technique for creating anti-icing coatings on wind-turbine blades and other outdoor apparatus. [ABSTRACT FROM AUTHOR]

Globally, wind turbines play a significant role in generating sustainable and clean energy. Ensuring optimal performance and reliability is crucial to minimize failures and reduce operating and maintenance costs. However, due to their conventional design, identifying faults in wind turbines is challenging. This dataset provides vibration data for faulty wind turbine blades, which covers common vibration excitation mechanisms associated with various faults and operating conditions, including wind speed. The introduced faults in the wind turbine blades include surface erosion, cracked blade, mass imbalance, and twist blade fault. This data article serves as a valuable resource for validating condition monitoring methods in industrial wind turbine applications and facilitates a better understanding of vibration signal characteristics associated with different faults.

A wireless monitoring system based on piezoelectric energy harvesting (PEH) is presented to provide fatigue data of wind turbine blades in operation. The system comprises three subsystems, each respectively providing the following functions: (i) the conversion of mechanical to electric energy by exploiting the bistable vibration of a composite beam with piezoelectric patches in post-buckling, (ii) harvesting the converted energy by means of a modified, commercial, off-the-shelf (COTS) circuit to feed a LiPo battery and (iii) the battery-powered acquisition and wireless transmission of sensory signals to the cloud to be elaborated upon by the end-user. The system was verified with ground tests under representative operation conditions, which demonstrated the fulfillment of the design requirements. The measurements indicated that the system provided 23% of the required power for fully autonomous operation when subjected to white noise base excitation of 1 g acceleration in the range of 1–20 Hz.

In recent trends, a rising demand for renewable energy has driven wind turbines to larger proportions, where lighter blade designs are often adopted to reduce the costs associated with logistics and production. This causes modern utility-scale wind turbine blades to be inherently more flexible, and their amplified aeroelastic sensitivity results in complex multi-physics reactions to variant atmospheric conditions, including dynamic patterns of aerodynamic loading at the rotor and vortex structure evolutions within the wake. In this paper, we analyze the influence of inflow variance for wind turbines with large, flexible rotors through simulations of the National Rotor Testbed (NRT) turbine, located at Sandia National Labs’ Scaled Wind Farm Technology (SWiFT) facility in Lubbock, Texas. The Common Ordinary Differential Equation Framework (CODEF) modeling suite is used to simulate wind turbine aeroelastic oscillatory behavior and wind farm vortex wake interactions for a range of flexible NRT blade variations, operating in differing conditions of variant atmospheric flow. CODEF solutions of turbine operation in Steady-In-The-Average (SITA) wind conditions are compared to SITA wind conditions featuring a controlled gust-like pulse overimposed, to isolate the effects of typical wind fluctuations. Finally, simulations of realistic time-varying wind conditions from SWiFT meteorological tower measurements are compared to the solutions of SITA wind conditions. These increasingly complex atmospheric inflow variations are tested to show the differing effects evoked by various patterns of spatiotemporal atmospheric flow fluctuations. An analysis is presented for solutions of wind turbine aeroelastic response and vortex wake evolution, to elucidate the consequences of variant inflow, which pertain to wind turbine dynamics at an individual and farm-collective scale. The comparisons of simulated farm flow for SITA and measured fluctuating wind conditions show that certain regions of the wake contain up to a 12% difference in normalized axial velocity, due to the introduction of wind fluctuations. The findings of this study prove valuable for practical applications in wind farm control and optimization strategies, with particular significance for modern utility-scale wind power plants operating in variant atmospheric conditions.

As wind turbine blade length increases, reconciling lightweight design with strength necessitates continuous advancements in process technology. The impact of three different process technologies–vacuum-assisted resin transfer moulding (VARTM), prepreg, and pultrusion–on the properties of wind turbine blade composite spar caps was investigated using scanning electron microscopy, dynamic mechanical analysis, differential scanning calorimetry, thermogravimetric analysis, and static and fatigue testing. The results demonstrated that the fibre weight content and 0° tensile modulus of the VARTM and pultrusion composites increased as compared to those of the prepreg samples. Subsequently, the properties of a 94-m blade were analysed using the Ansys Composite PrepPost (ACP) and static structure modules in Ansys simulations, and the weights of the spar cap were compared with test data of materials under different process technologies. The results showed that the masses of the spar cap of a 94-m blade in the pultrusion, VARTM, and prepreg processes were 7965, 9170, and 9942 kg, respectively. The quantitative influence rules on the weight of the wind turbine blade spar cap prepared through different process technologies were formulated. The findings of this study are promising and are expected to aid the development of wind turbine blade process technologies.

Leading edge erosion of wind turbine blades causes roughening of the blade’s surface, leading to a reduction of energy production. This paper presents a computational model for the prediction of the roughness evolution of the blade’s surface, based on fatigue damage calculations and rain droplet impact simulations. A novel method for the calculation of material roughness due to multiple random liquid impacts was developed, by considering damage concentration in areas where sharpness due to material removal is formed. Material removal was governed by fatigue damage values. The computational model was compared to roughness measurements from a sample tested in a rain erosion tester. The outputs of this model are 3D surfaces resembling the roughness of the protective coating layer as well as the evolution of surface roughness parameters and mass loss throughout time.

Aspects concerning resonance and global stability of a wind turbine blade must be carefully considered in its optimal design. In this paper, a composite wind turbine blade with an external geometry based on the NREL 5 MW model was subjected to multi-objective structural optimization considering these aspects. Four multi-objective structural optimization problems are formulated considering the blade mass, the maximum blade tip displacement, the natural frequencies of vibration, and the critical load factor as objective functions. The design variables are the number of plies, material, and fiber orientation. The design constraints are the materials' margin of safety, the blade's allowable tip displacement, and the minimum load factor. The blade model is submitted to the loads determined by the actuator lines theory and discretized in a finite element parameterized model using the Femap software according to geometric design variables. Among many multi-objective evolutionary algorithms available in the literature concerning evolutionary computation, the NSGA-II is the adopted evolutionary algorithm to solve the multi-objective optimization problems. Pareto fronts are obtained and performance indicators are used to evaluate the distribution of the non-dominated solutions. Multi-criteria decision-making is used to extract the solutions from the Pareto fronts according to the decision-maker's preferences. The values of the objective functions, design variables, and constraints are presented for each extracted solution. The proposed study is expected to contribute to the multi-objective optimization and the structural design of wind turbine blades. [ABSTRACT FROM AUTHOR]

This work aims to propose a method enabling the evaluation of wind turbine blade damage and fatigue related to a 1 Hz wind speed signal applied to a large period and based on standard 10-min SCADA data. Previous studies emphasize the need for sampling with a 1 Hz frequency when carrying out blade damage computation. However, such methods cannot be applied to evaluate the damage for a long period of time due to the complexity of computation and data availability. Moreover, 1 Hz SCADA data are not commonly used in the wind farm industry because they require a large data storage capacity. Applying such an approach, which is based on a 1 Hz wind speed signal, to current wind farms is not a trivial pursuit. The present work investigates the possibility of overcoming the preceding issues by estimating the equivalent 1 Hz wind speed damage over a 10-min period characterized by SCADA data in terms of measured mean wind speed and turbulence intensity. Then, a discussion is carried out regarding a method to estimate the uncertainty of the simulation, in a bid to come up with a tool facilitating decision-making by the operator. A statistical analysis of the damage assessed for different wind turbines is thus proposed to determine which one has sustained the most damage. Finally, the probability of reaching a critical damage level over time is then proposed, allowing the operator to optimize the operating and maintenance schedule. [ABSTRACT FROM AUTHOR]

In this study, airfoil shape optimization of a wind turbine blade is performed using the ANSYS Fluent Adjoint Solver. The aim of this optimization process is to increase the wind turbine output power, and the objective function is to maximize the airfoil lift to drag ratio (CL/CD). This study is applied to the NREL phase VI wind turbine, therefore, the S809 airfoil is used as a reference profile. First, for the validation of the applied numerical model, steady-state simulations are carried out for the S809 airfoil at various angles of attack. Then, the optimization is performed with the airfoil set at a fixed angle of attack, 𝐴𝑂𝐴 = 6.1°, considering three Reynolds numbers, 𝑅𝑒 = 3 105, 4.8 105 and 106. Next, computations are performed for the fluid flow around the optimized airfoils at angles of attack ranging from 0° to 20°. The results show that (i) the lift to drag ratios of the optimized airfoils are significantly improved compared to the baseline S809 airfoil, (ii) this improvement is sensitive to the Reynolds number, and (iii) the CL/CD ratios are also improved for another angle of attack values. Thereafter, the optimized airfoils are used for the design of the NREL Phase VI blade and the aerodynamic performances of this new wind turbine are assessed using the open-source code QBlade. These latter results indicate that when the blades are designed with the optimized airfoils, the wind turbine aerodynamic performances increase significantly. Indeed, at a wind speed of 10 m/s, the power output of the wind turbine is improved by about 38% compared to that of the original turbine. [ABSTRACT FROM AUTHOR]

Wind turbines operating in cold regions are prone to blade icing, which seriously affects their aerodynamic characteristics and safety performance. Coatings are one of the effective solutions to the icing problem on wind turbine blades. In this study, MoS2/ZnO/PDMS superhydrophobic nano-anti-icing coatings were prepared using the hydrothermal method and the liquid phase method. SEM revealed that the MoS2/ZnO coating was a typical superhydrophobic nanostructure with an ultra-thin sheet-like morphology of clusters and a hilly nano-rough structure, with contact angles (CA) of 152.1° and 4.7° with water droplets and the sliding angle (SA), respectively. The MoS2/ZnO/PDMS coating had an adhesion strength to ice of 78 kPa, which was 60.2% lower than an uncoated surface. The icing effects of the NACA0018 airfoil blade model with or without MoS2/ZnO coatings were studied at different ambient temperatures and wind speeds using the icing wind tunnel test. The results showed that, compared to uncoated blades, the level of icing was lower on the blade airfoil surface that was coated with MoS2/ZnO. At 10 m/s and −10 °C, the icing thickness and icing area of the leading edge of the blade airfoil were 13.7% and 28.3% lower, respectively. This study provides a valuable reference for the development of anti-icing coatings for wind turbine blades. [ABSTRACT FROM AUTHOR]

This paper examines the potential for reducing the cost of energy for super-scale wind turbines through the use of a downwind configuration. Using nonlinear aeroelastic modeling, the responses of 10 MW upwind and downwind wind turbine blades are simulated and compared under shear wind conditions. The study evaluates the impact of both nonlinear and linear aeroelastic models on the dynamic response of different blade sizes, highlighting the need for a nonlinear approach. Results indicate that the linear model overestimates blade deformations (18.14%) and the nonlinear model is more accurate for predicting the aeroelastic response of ultra-long blades of 86.35 m. The study also finds that the downwind turbine blade experiences smaller flapwise moment (17.53%), and blade tip flapwise deformation (33.97%) than the upwind turbine blade, with increased load and deformation fluctuation as wind shear increases. [ABSTRACT FROM AUTHOR]

The work performance of stereo digital image correlation (stereo-DIC) technologies, especially the operating accuracy and reliability in field applications, is not fully understood. In this study, the key technologies of the field remote 3D displacement sensing of civil structures based on stereo-DIC have been proposed. An image correlation algorithm is incorporated in improving the matching accuracy of control points. An adaptive stereo-DIC extrinsic parameter calibration method is developed by fusing epipolar-geometry-based and homography-based methods. Furthermore, a reliable reference frame that does not require artificial markers is established based on Euclidean transformation, which facilitates in-plane and out-of-plane displacement monitoring for civil structures. Moreover, a camera motion correction is introduced by considering background points according to the camera motion model. With an experiment, the feasibility and accuracy of the proposed system are validated. Moreover, the system is applied to sense the dynamic operating displacement of a 2 MW wind turbine's blades. The results show the potential capability of the proposed stereo-DIC system in remote capturing the full-field 3D dynamic responses and health status of large-scale structures. [ABSTRACT FROM AUTHOR]

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A significant problem associated with the implementation of Vibration-Based Structural Health Monitoring (VSHM) systems originates from the detrimental effects caused by Environmental and Operational Variations (EOVs). The EOVs cause observations from the same structural condition to behave in different manners. As such, this leads to issues when defining a robust baseline state as well as making the discrimination between undamaged and damaged observations more challenging. In order to address these challenges, multivariate nonlinear regression is implemented to account for the EOVs. Damage Sensitive Features (DSFs) are extracted from acceleration data and then are regressed based on environmental and operational parameters. New features are effectively normalised by finding the difference between the measured and predicted values. This process removes the influence of the EOVs in an explicit manner, allowing for more reliable damage detection. While the benefit of the application of different regression methodologies has already been demonstrated in the past, this work addresses a number of practicalities in the implementation of VSHM on real systems. The analysis investigates the selection of the DSF and is investigated alongside another analysis into how the damage detection behaves under varying amounts of input information. Furthermore, a method is proposed to understand and account for a large number of outliers in the training data. [ABSTRACT FROM AUTHOR]