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1
Aoujdad, Khalid, BA Elhadji-Amadou, Pierre Marechal, Damien Leduc, Alexandre Vivet, Florian Gehring e Mounsif ECH-CHERIF El-Kettani. "Integrated analysis of materials for offshore wind turbine blades: mechanical and acoustical coupling". Journal of Physics: Conference Series 2904, n. 1 (1 novembre 2024): 012004. http://dx.doi.org/10.1088/1742-6596/2904/1/012004.
Testo completoAbstract (sommario):
Abstract This work focuses on assessing the structural degradation of offshore wind turbine blade (OWTB) materials caused by exposure to the marine environment using acoustic and mechanical methods. Samples, consisting of a glass fibre reinforced polymer (GFRP) composite laminate with a styrene-acrylo-nitrile (SAN) foam core, are subjected to an accelerated hygrothermal ageing by immersion in seawater at 28-30% salinity, thermostated at 40°C. Non-destructive characterisation using ultrasonic waves and mechanical testing, including 3- and 4-point bending tests, are carried out. These results are in agreement with mechanical tests which show an 8% reduction in maximum stress for the same immersion time.
2
Bhattacharya, Subhamoy, Suryakanta Biswal, Muhammed Aleem, Sadra Amani, Athul Prabhakaran, Ganga Prakhya, Domenico Lombardi e Harsh K. Mistry. "Seismic Design of Offshore Wind Turbines: Good, Bad and Unknowns". Energies 14, n. 12 (12 giugno 2021): 3496. http://dx.doi.org/10.3390/en14123496.
Testo completoAbstract (sommario):
Large scale offshore wind farms are relatively new infrastructures and are being deployed in regions prone to earthquakes. Offshore wind farms comprise of both offshore wind turbines (OWTs) and balance of plants (BOP) facilities, such as inter-array and export cables, grid connection etc. An OWT structure can be either grounded systems (rigidly anchored to the seabed) or floating systems (with tension legs or catenary cables). OWTs are dynamically-sensitive structures made of a long slender tower with a top-heavy mass, known as Nacelle, to which a heavy rotating mass (hub and blades) is attached. These structures, apart from the variable environmental wind and wave loads, may also be subjected to earthquake related hazards in seismic zones. The earthquake hazards that can affect offshore wind farm are fault displacement, seismic shaking, subsurface liquefaction, submarine landslides, tsunami effects and a combination thereof. Procedures for seismic designing OWTs are not explicitly mentioned in current codes of practice. The aim of the paper is to discuss the seismic related challenges in the analysis and design of offshore wind farms and wind turbine structures. Different types of grounded and floating systems are considered to evaluate the seismic related effects. However, emphasis is provided on Tension Leg Platform (TLP) type floating wind turbine. Future research needs are also identified.
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Vuong, Nguyen Van, e Mai Hong Quan. "Fatigue analysis of jacket support structure for offshore wind turbines". Journal of Science and Technology in Civil Engineering (STCE) - NUCE 13, n. 1 (31 gennaio 2019): 46–59. http://dx.doi.org/10.31814/stce.nuce2019-13(1)-05.
Testo completoAbstract (sommario):
In the past few decades and up to now, the fossil energy has exerted tremendous impacts on human environments and gives rise to greenhouse effects while the wind power, especially in offshore region, is an attractive renewable energy resource. For offshore fixed wind turbine, stronger foundation like jacket structure has a good applicability for deeper water depth. Once water depth increases, dynamic responses of offshore wind turbine (OWT) support structures become an important issue. The primary factor will be the total height of support structure increases when wind turbine is installed at offshore locations with deeper water depth, in other words the fatigue life of each components of support structure decrease. The other one will experience more wind forces due to its large blades, apart from wave, current forces, when makes a comparison with offshore oil and gas platforms. Summing up two above reasons, fatigue analysis, in this research, is a crucial aspect for design of offshore wind turbine structures which are subjected to time series wind, wave loads and carried out by aiding of SACS software for model simulation (P-M rules and S-N curves) and Matlab code. Results show that the fatigue life of OWT is decreased accordingly by increasing the wind speed acting on the blades, especially with the simultaneous interaction between wind and wind-induced wave. Hence, this should be considered in wind turbine design.
Keywords: offshore wind turbine; Jacket structure; fatigue analysis; P-M rules; S-N curves.
Received 01 October 2018, Revised 19 November 2018, Accepted 31 January 2019
4
Wen, K. Z., D. Dehtyriov e B. W. Byrne. "Assessing aerodynamic influences on offshore foundation design for large wind farms". Journal of Physics: Conference Series 2745, n. 1 (1 aprile 2024): 012023. http://dx.doi.org/10.1088/1742-6596/2745/1/012023.
Testo completoAbstract (sommario):
Abstract An evaluation of the impact of aerodynamic interactions on offshore wind turbine (OWT) monopile design in large wind farms is presented. The interactions between turbines within a wind farm, and between the atmosphere and the entire wind-farm, act to reduce the mean effective loads across the farm. This reduction impacts the operational performance of OWT foundations in two notable ways: a decrease in turbine structural loads which affects design to serviceability limit state and a shift in excitation frequencies of the passing blades which impacts fatigue performance. To assess the implications on monopile design, we conduct static and dynamic analyses using a 1-D finite element model (FEM). We show that the farmatmosphere interaction effect leads to marked reduction in monopile lengths between ∼ 5 − 25% across an entire wind farm. The dynamic analysis reveals a competing balance between shifting frequency bands and reduced wind loads on the fatigue response. The monopile design is found to be strongly dependent on wind farm size and ratio of wind to wave loading, with wave loading coupled to the farm-atmosphere interaction effect. Exploiting these interactions plays a pivotal role in reducing the levelised cost of wind energy and ensuring robust design of OWTs.
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Roni Sahroni, Taufik. "Modeling and Simulation of Offshore Wind Power Platform for 5 MW Baseline NREL Turbine". Scientific World Journal 2015 (2015): 1–11. http://dx.doi.org/10.1155/2015/819384.
Testo completoAbstract (sommario):
This paper presents the modeling and simulation of offshore wind power platform for oil and gas companies. Wind energy has become the fastest growing renewable energy in the world and major gains in terms of energy generation are achievable when turbines are moved offshore. The objective of this project is to propose new design of an offshore wind power platform. Offshore wind turbine (OWT) is composed of three main structures comprising the rotor/blades, the tower nacelle, and the supporting structure. The modeling analysis was focused on the nacelle and supporting structure. The completed final design was analyzed using finite element modeling tool ANSYS to obtain the structure’s response towards loading conditions and to ensure it complies with guidelines laid out by classification authority Det Norske Veritas. As a result, a new model of the offshore wind power platform for 5 MW Baseline NREL turbine was proposed.
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Algolfat, Amna, Weizhuo Wang e Alhussein Albarbar. "The Sensitivity of 5MW Wind Turbine Blade Sections to the Existence of Damage". Energies 16, n. 3 (28 gennaio 2023): 1367. http://dx.doi.org/10.3390/en16031367.
Testo completoAbstract (sommario):
Due to the large size of offshore wind turbine blades (OWTBs) and the corrosive nature of salt water, OWTs need to be safer and more reliable that their onshore counterparts. To ensure blade reliability, an accurate and computationally efficient structural dynamic model is an essential ingredient. If damage occurs to the structure, the intrinsic properties will change, e.g., stiffness reduction. Therefore, the blade’s dynamic characteristics will differ from those of the intact ones. Hence, symptoms of the damage are reflected in the dynamic characteristics that can be extracted from the damaged blade. Thus, damage identification in OWTBs has become a significant research focus. In this study, modal model characteristics were used for developing an effective damage detection method for WTBs. The technique was used to identify the performance of the blade’s sections and discover the warning signs of damage. The method was based on a vibration-based technique. It was adopted by investigating the influence of reduced blade element rigidity and its effect on the other blade elements. A computational structural dynamics model using Rayleigh beam theory was employed to investigate the behaviour of each blade section. The National Renewable Energy Laboratory (NREL) 5MW blade benchmark was used to demonstrate the behaviour of different blade elements. Compared to previous studies in the literature, where only the simple structures were used, the present study offers a more comprehensive method to identify damage and determine the performance of complicated WTB sections. This technique can be implemented to identify the damage’s existence, and for diagnosis and decision support. The element most sensitive to damage was element number 14, which is NACA_64_618.
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Zhang, Peng, Zhengjie He, Chunyi Cui, Liang Ren e Ruqing Yao. "Operational Modal Analysis of Offshore Wind Turbine Tower under Ambient Excitation". Journal of Marine Science and Engineering 10, n. 12 (9 dicembre 2022): 1963. http://dx.doi.org/10.3390/jmse10121963.
Testo completoAbstract (sommario):
The condition of an offshore wind turbine (OWT) should be monitored to assure its reliability against various environmental loads and affections. The modal parameters of the OWT can be used as an indicator of its condition. This paper combines the Kalman filter, the random decrement technique (RDT), and the stochastic subspace identification (SSI) methods and proposes an RDT-SSI method to estimate the operational frequency of an OWT subjected to ambient excitation. This method imposes no requirement on the input/loads; therefore, it is relatively easy for field application. An experimental study with a small-scale OWT was conducted to verify the accuracy of the proposed RDT-SSI method. The test results implied that the frequency estimated by the RDT-SSI method is close to that estimated by an impact hammer test. Moreover, the small-scale OWT was buried at different embedment depths to simulate the influence of the scouring phenomenon, and the frequency of the OWT decreased with decreasing embedment depth. Additionally, the bolts at the root of the turbine blades were also loosened to investigate their influence on the frequency. As more blades were loosened, the identified frequency of the OWT also decreased, indicating that the proposed RDT-SSI method can be employed for the health monitoring of an OWT.
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Lian, Jijian, Ou Cai, Xiaofeng Dong, Qi Jiang e Yue Zhao. "Health Monitoring and Safety Evaluation of the Offshore Wind Turbine Structure: A Review and Discussion of Future Development". Sustainability 11, n. 2 (18 gennaio 2019): 494. http://dx.doi.org/10.3390/su11020494.
Testo completoAbstract (sommario):
With the depletion of fossil energy, offshore wind power has become an irreplaceable energy source for most countries in the world. In recent years, offshore wind power generation has presented the gradual development trend of larger capacity, taller towers, and longer blades. The more flexible towers and blades have led to the structural operational safety of the offshore wind turbine (OWT) receiving increasing worldwide attention. From this perspective, health monitoring systems and operational safety evaluation techniques of the offshore wind turbine structure, including the monitoring system category, data acquisition and transmission, feature information extraction and identification, safety evaluation and reliability analysis, and the intelligent operation and maintenance, were systematically investigated and summarized in this paper. Furthermore, a review of the current status, advantages, disadvantages, and the future development trend of existing systems and techniques was also carried out. Particularly, the offshore wind power industry will continue to develop into deep ocean areas in the next 30 years in China. Practical and reliable health monitoring systems and safety evaluation techniques are increasingly critical for offshore wind farms. Simultaneously, they have great significance for strengthening operation management, making efficient decisions, and reducing failure risks, and are also the key link in ensuring safe energy compositions and achieving energy development targets in China. The aims of this article are to inform more scholars and experts about the status of the health monitoring and safety evaluation of the offshore wind turbine structure, and to contribute toward improving the efficiency of the corresponding systems and techniques.
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Colherinhas, G. B., F. Petrini e M. V. G. de Morais. "Risk mitigation/performances incrementation of an offshore wind turbine with a flexible monopile foundation by means of a pendulum-tuned mass damper". Journal of Physics: Conference Series 2647, n. 3 (1 giugno 2024): 032011. http://dx.doi.org/10.1088/1742-6596/2647/3/032011.
Testo completoAbstract (sommario):
Abstract This paper proposes a multi-level system modeling for studying the structural behavior of an Offshore Wind Turbine (OWT) with a flexible monopile foundation considering the Pile-Soil Interaction (PSI). This analysis shows that the structural response is affected by a significant uncertainty due to the randomness of the geometric and mechanical properties of the tower and foundation and by the environmental loads and rotating blades. With a Monte Carlo simulation, the sources of uncertainty of the so-called “environmental” and “exchange” zones are generated for a Performance-Based Wind Engineering (PBWE) design of OWTs. Hence, the structural response, the stresses along the foundation, and the power production are evaluated in probabilistic terms assisting the optimal design process of a Pendulum Tuned Mass Damper (PTMD) used to mitigate the structural vibration of an OWT.
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Tong, Yihui, Weitao Liu, Xuanyi Liu, Peng Wang, Zhe Sheng, Shengquan Li, Hao Zhang et al. "Materials Design and Structural Health Monitoring of Horizontal Axis Offshore Wind Turbines: A State-of-the-Art Review". Materials 18, n. 2 (13 gennaio 2025): 329. https://doi.org/10.3390/ma18020329.
Testo completoAbstract (sommario):
In recent decades, Offshore Wind Turbines (OWTs) have become crucial to the clean energy transition, yet they face significant safety challenges due to harsh marine conditions. Key issues include blade damage, material corrosion, and structural degradation, necessitating advanced materials and real-time monitoring systems for enhanced reliability. Carbon fiber has emerged as a preferred material for turbine blades due to its strength-to-weight ratio, although its high cost remains a barrier. Structural Health Monitoring Systems (SHMS) play a vital role in detecting potential faults through real-time data on structural responses and environmental conditions. Effective monitoring approaches include vibration analysis and acoustic emission detection, which facilitate early identification of anomalies. Additionally, robust data transmission technologies are essential for SHMS effectiveness. This paper reviews material design strategies, data acquisition methods, and safety assessment techniques for OWTs, addressing current challenges and future directions in the field.
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Partovi-Mehr, Nasim, John DeFrancisci, Mohsen Minaeijavid, Babak Moaveni, Daniel Kuchma, Christopher D. P. Baxter, Eric M. Hines e Aaron S. Bradshaw. "Fatigue Analysis of a Jacket-Supported Offshore Wind Turbine at Block Island Wind Farm". Sensors 24, n. 10 (9 maggio 2024): 3009. http://dx.doi.org/10.3390/s24103009.
Testo completoAbstract (sommario):
Offshore wind-turbine (OWT) support structures are subjected to cyclic dynamic loads with variations in loadings from wind and waves as well as the rotation of blades throughout their lifetime. The magnitude and extent of the cyclic loading can create a fatigue limit state controlling the design of support structures. In this paper, the remaining fatigue life of the support structure for a GE Haliade 6 MW fixed-bottom jacket offshore wind turbine within the Block Island Wind Farm (BIWF) is assessed. The fatigue damage to the tower and the jacket support structure using stress time histories at instrumented and non-instrumented locations are processed. Two validated finite-element models are utilized for assessing the stress cycles. The modal expansion method and a simplified approach using static calculations of the responses are employed to estimate the stress at the non-instrumented locations—known as virtual sensors. It is found that the hotspots at the base of the tower have longer service lives than the jacket. The fatigue damage to the jacket leg joints is less than 20% and 40% of its fatigue capacity during the 25-year design lifetime of the BIWF OWT, using the modal expansion method and the simplified static approach, respectively.
12
Lei, Zhenbo, Gang Liu, Xuesen Zhang, Qingshan Yang e S. S. Law. "Three-Dimensional Prestressed Tuned Mass Damper for Passive Vibration Control of Coupled Multiple DOFs Offshore Wind Turbine". Structural Control and Health Monitoring 2023 (14 settembre 2023): 1–27. http://dx.doi.org/10.1155/2023/8897653.
Testo completoAbstract (sommario):
Large megawatts offshore wind turbine (OWT) with low natural frequency and low damping is subjected to significant vibration from wind and wave actions in its service environment. The one-dimensional prestressed tuned mass damper (PSTMD) is further extended to a 3D-PSTMD for the control of vibrations of the OWT in this paper. A multiple DOFs coupled system of turbine, blades, tower, and foundation under aerodynamic and hydrodynamic forces is considered in this study of vibration mitigation at fore-aft and side-side directions. The dynamic model is derived with the Lagrangian equation, and the superiorities of the PSTMD are proved from the perspective of theoretical analysis. Aerodynamic and hydrodynamic loads are generated with the blade element momentum (BEM) theory and Morrison equation, and the dynamic responses of different systems are computed by using the Wilson-θ method. The analysis results indicate that a damping coefficient of the 3D-PSTMD corresponding to the first vibration mode can be tuned to take up values larger than that in traditional three-dimensional pendulum (TMD) (3D-PTMD). The bidirectional vibration suppression competences of the 3D-PSTMD in the dynamic responses when under aerodynamic and hydrodynamic loads are better than those of the traditional 3D-PTMD.
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Edirisinghe, Dylan S., Lilibeth A. Zambrano M., Edmond Tobin e Ashish Vashishtha. "CFD analysis of droplet impact pressure for prediction of rain erosion of wind turbine blades". Journal of Physics: Conference Series 2875, n. 1 (1 novembre 2024): 012019. http://dx.doi.org/10.1088/1742-6596/2875/1/012019.
Testo completoAbstract (sommario):
Abstract Rain erosion is a prominent issue in Offshore Wind Turbines (OWT) with wind farms experiencing heavy and frequent rainfall compared to onshore conditions. A simplified Springer model is used widely by industries to predict erosion initiation in composite materials and has been under various recent investigations to improve its predictability of rain erosion. However, the Springer model uses the modified water hammer equation to compute impact pressure, and it does not consider the impact of droplet sizes. This Computational Fluid Dynamic (CFD) study is motivated to develop an understanding of the effect of droplet sizes on impact pressure while discussing impact behaviour in detail. Simulations were conducted for droplet diameters ranging between 1 to 5 mm with an impact speed of 100 m/s. The results show that the water droplets slightly deform just before the impact, delaying the impact time due to the pressurised air layer in between the droplet and substrate. During this delay period, the impact pressure was significantly increased to reach the maximum impact pressure. Maximum impact pressure was found to increase with the droplet size, due to high air volume displacement whereas, this phenomenon is not accounted for in pressure estimation in the Springer model. In conclusion, the larger droplets were observed to impose higher pressure on the blade’s coating than the smaller droplets, which can lead to high erosion levels.
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Ye, Kehua, Chun Li, Fudong Chen, Zifei Xu, Wanfu Zhang e Junwei Zhang. "Floating Ice Load Reduction of Offshore Wind Turbines by Two Approaches". International Journal of Structural Stability and Dynamics 18, n. 10 (ottobre 2018): 1850129. http://dx.doi.org/10.1142/s0219455418501298.
Testo completoAbstract (sommario):
The offshore wind turbines (OWTs) constructed at the northern sea areas under cold climate are frequently subjected to floating ice loads. It is imperative to reduce the damage owing to the floating ice with some appropriate approaches. The purpose of this paper is to ascertain the effectiveness of the tuned mass damper (TMD) and the ice-breaking cone for reducing floating ice loads on OWTs. The National Renewable Energy Laboratory's (NREL) 5 MW OWT, which is treated as a multibody system with rigid and flexible parts, is adopted as the example model here. The multiple loads taken into consideration in the fully coupled simulation include floating ice and turbulent wind. The aerodynamic load acting on the blades is solved by the blade element momentum method based on a full-field turbulent wind farm generated by the Kaimal spectrum. The Matlock model and the Ralston model are adopted for evaluating the floating ice loads on the cylindrical and conical structures, respectively. The TMD system in the nacelle and the ice-breaking cone on the tower at the mean sea level are the two load reduction approaches of concern in this paper. A weak aeroelastic simulation of the OWT model is conducted. The solution of flexibility effectiveness depends on some accurate mode shapes by the linear modal representation. Finally, Kane's method is used for predicting the motion of the whole OWT. The relevant results reveal some positive effectiveness of the TMD system and the ice-breaking cone for reducing the floating ice load. The displacement of tower top decreases significantly with the utilization of the two approaches. The TMD system has a better performance for the side-side displacement than the fore-aft displacement. By switching the ice failure mode from crushing to bending, the ice-breaking cone reduces the floating load more effectively than the TMD system. It affects equally significantly the fore-aft and side-side displacements.
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Partovi-Mehr, Nasim, Emmanuel Branlard, Mingming Song, Babak Moaveni, Eric M. Hines e Amy Robertson. "Sensitivity Analysis of Modal Parameters of a Jacket Offshore Wind Turbine to Operational Conditions". Journal of Marine Science and Engineering 11, n. 8 (30 luglio 2023): 1524. http://dx.doi.org/10.3390/jmse11081524.
Testo completoAbstract (sommario):
Accurate estimation of offshore wind turbine (OWT) modal parameters has a prominent effect on the design loads, lifetime prediction, and dynamic response of the system. Modal parameters can vary during the operation of OWTs. This paper studies the variation and sensitivity analysis of an OWT’s modal parameters with respect to operational and environmental conditions. Three finite element models of a jacket-supported OWT at the Block Island Wind Farm are created within the OpenSees, SAP2000, and OpenFAST platforms and validated using experimental measurements. The OpenFAST model is used to simulate the modal parameters of the turbine under various wind speed, rotor speed, power, yaw angle, mean sea level, blade pitch angle, and soil spring values. The model-predicted modal parameters of the first fore–aft (FA) and side–side (SS) modes are compared to those identified from experimental measurements. Results from the simulations show that the first FA natural frequency and damping ratio mostly depend on the rotor speed and wind speed, respectively, while yaw angle and mean sea level do not have a visible effect. It is observed that there is about 8% stiffening in the first FA frequency and an aerodynamic damping of 7.5% during the operation of the OWT.
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Fu, Xiaohan, e Meiping Sheng. "Research on Structural Failure Analysis and Strengthening Design of Offshore Wind Turbine Blades". Journal of Marine Science and Engineering 10, n. 11 (4 novembre 2022): 1661. http://dx.doi.org/10.3390/jmse10111661.
Testo completoAbstract (sommario):
The existing blade protection mechanisms are highly dependent on the control system and its power supply. Safety of offshore wind turbines cannot be guaranteed under extreme weather when the control protection mechanisms fail. So far, not enough consideration has been given to the above problems in mechanical design for protecting wind turbine blades. In this paper, a reinforcing cable component (RCC) is proposed to improve the resistance ability of offshore wind turbine blades. The static model of the blades with reinforcing cable component was presented. The Finite Element (FE) simulation was performed for a 5 MW offshore wind turbine and load reduction effect of connection location for RCC was discussed according to the FE results. A static strain verification test was carried out. Simulation and test results indicate that the proposed reinforcing cable component effectively reduces the strain as well as the tip displacement of the blades. The proposed mechanical structure will help to enhance the survival ability of offshore wind turbine blades when the control protection system fails.
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Dong, Xiao Hui, Tie Jun Yuan e Ru Hong Ma. "Corrosion Mechanism on Offshore Wind Turbine Blade in Salt Fog Environment". Applied Mechanics and Materials 432 (settembre 2013): 258–62. http://dx.doi.org/10.4028/www.scientific.net/amm.432.258.
Testo completoAbstract (sommario):
Targeted at the phenomenon of offshore wind turbine blades cracking and tearing up, the corrosion mechanism on offshore wind turbine blade in salt fog environment is researched. By means of analyzing the blades structural damage and the corrosion in salt fog environment, the main damage forms of the blades can be summed up with a further view to discussing and analyzing the corrosion mechanism on offshore wind turbine blade in salt fog environment from the perspective of both physical and chemical corrosion. A final conclusion is reached which shows that the pitted surface of the blade developed from the pumping and milling of sand blown by wind is the incentive and hydrone diffusion and ultraviolet radiation are the main factors that lead to the aging of materials and corrosion of blades.
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Lai, Yongqing, Wei Li, Ben He, Gen Xiong, Renqiang Xi e Piguang Wang. "Influence of Blade Flexibility on the Dynamic Behaviors of Monopile-Supported Offshore Wind Turbines". Journal of Marine Science and Engineering 11, n. 11 (24 ottobre 2023): 2041. http://dx.doi.org/10.3390/jmse11112041.
Testo completoAbstract (sommario):
At present, monopole-supported offshore wind turbines (MOWTs) are widely used in offshore wind farms. The influence of blade flexibility on the dynamic behaviors of MOWTs excited by waves and earthquakes was investigated in this study. Numerical analysis models were established for 5 MW and 10 MW MOWTs, incorporating flexible and rigid blade configurations. The modes and natural frequencies of the full system were compared between these two numerical models, and their dynamic responses were evaluated under wave-only and earthquake-only excitations. It was revealed that the influence of blade flexibility on the first- and second-order modes of the system can be neglected. The dynamic response of these MOWTs under wave excitation can be predicted by the rigid blade model, where the maximum relative difference is less than 5%. However, higher-order modes of the system are significantly affected by the blade flexibility. Under high-frequency excitations, these higher-order modes of the system are remarkably stimulated. Additionally, a large relative difference, exceeding 50%, is detected when the rigid blade model is used to predict the seismic response of the two MOWTs. Consequently, the blade flexibility should be adequately modeled when predicting the dynamic response of OWTs.
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Hua, Xugang, Qingshen Meng, Bei Chen e Zili Zhang. "Structural damping sensitivity affecting the flutter performance of a 10-MW offshore wind turbine". Advances in Structural Engineering 23, n. 14 (15 giugno 2020): 3037–47. http://dx.doi.org/10.1177/1369433220927260.
Testo completoAbstract (sommario):
Classical flutter of wind turbine blades is one of the most destructive instability phenomena of wind turbines especially for several-MW-scale turbines. In the present work, flutter performance of the DTU 10-MW offshore wind turbine is investigated using a 907-degree-of-freedom aero-hydro-servo-elastic wind turbine model. This model involves the couplings between tower, blades and drivetrain vibrations. Furthermore, the three-dimensional aerodynamic effects on wind turbine blade tip have also been considered through the blade element momentum theory with Bak’s stall delay model and Shen’s tip loss correction model. Numerical simulations have been carried out using data calibrated to the referential DTU 10-MW offshore wind turbine. Comparison of the aeroelastic responses between the onshore and offshore wind turbines is made. Effect of structural damping on the flutter speed of this 10-MW offshore wind turbine is investigated. Results show that the damping in the torsional mode has predominant impact on the flutter limits in comparison with that in the bending mode. Furthermore, for shallow water offshore wind turbines, hydrodynamic loads have small effects on its aeroelastic response.
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Ju, Shen-Haw, Yu-Cheng Huang e Hsin-Hsiang Hsu. "Parallel Analysis of Offshore Wind Turbine Structures under Ultimate Loads". Applied Sciences 9, n. 21 (4 novembre 2019): 4708. http://dx.doi.org/10.3390/app9214708.
Testo completoAbstract (sommario):
This paper investigates efficient design of offshore wind turbine (OWT) support structures under ultimate loads and proposes three schemes to overcome excessive computer time due to many required external loads. The first is the assumption of a rigid support structure to find blade wind forces, so that these forces are only dependent on wind profiles, which limits different cases in the structural analyses. Since the blade information is often confidential in turbine companies, this two-stage analysis allows the hub force to be the input data for the support structure design. The second is using a few control loads to perform the steel design between the second and the second-last design cycles. The third is using parallel computational procedures, since all loading cases can be independently executed in different CPU cores and computers. The test cases, with 5044 loading cases, indicate that the proposed method is fully parallel and can complete the design procedures using a few personal computers within several days. Test cases include IEC 61400-3, tropical cyclone, and seismic loads; although there are many loads to be considered, steel design is governed by a limited number of load cases, which are discussed in this paper.
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Asim, Taimoor, Sheikh Zahidul Islam, Arman Hemmati e Muhammad Saif Ullah Khalid. "A Review of Recent Advancements in Offshore Wind Turbine Technology". Energies 15, n. 2 (14 gennaio 2022): 579. http://dx.doi.org/10.3390/en15020579.
Testo completoAbstract (sommario):
Offshore wind turbines are becoming increasingly popular due to their higher wind energy harnessing capabilities and lower visual pollution. Researchers around the globe have been reporting significant scientific advancements in offshore wind turbines technology, addressing key issues, such as aerodynamic characteristics of turbine blades, dynamic response of the turbine, structural integrity of the turbine foundation, design of the mooring cables, ground scouring and cost modelling for commercial viability. These investigations range from component-level design and analysis to system-level response and optimization using a multitude of analytical, empirical and numerical techniques. With such wide-ranging studies available in the public domain, there is a need to carry out an extensive yet critical literature review on the recent advancements in offshore wind turbine technology. Offshore wind turbine blades’ aerodynamics and the structural integrity of offshore wind turbines are of particular importance, which can lead towards system’s optimal design and operation, leading to reduced maintenance costs. Thus, in this study, our focus is to highlight key knowledge gaps in the scientific investigations on offshore wind turbines’ aerodynamic and structural response. It is envisaged that this study will pave the way for future concentrated efforts in better understanding the complex behavior of these machines.
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Reinhardt, T., C. Sastre Jurado, W. Weijtjens e C. Devriendt. "On the influence of rotor nacelle assembly modelling on the computed eigenfrequencies of offshore wind turbines". Journal of Physics: Conference Series 2767, n. 5 (1 giugno 2024): 052034. http://dx.doi.org/10.1088/1742-6596/2767/5/052034.
Testo completoAbstract (sommario):
Abstract Motivated by the mismatch of measured and computed eigenfrequencies for the second tower mode of offshore wind turbines as well as previous studies examining the influence of including flexible blades in structural models, the need to extend the current integrated model to include flexible blades became apparent. A basic modelling approach which takes the blades as beam elements was implemented in an in-house finite element model of offshore wind turbines and benchmarked for the NREL 5 MW reference turbine with OpenFast. Moreover, the modelling approach was benchmarked with measurements that were obtained during the installation of a Belgian offshore wind turbine. The inclusion of flexible blades is shown to have a significant influence on the second tower mode and is able to reduce the mismatch between measurements and computations. Furthermore, the capability of the inclusion of flexible blades to model the effects of additional parameters is presented. Overall, the need to extend the rotor nacelle modelling in structural models of offshore wind turbines beyond a lumped mass approach is demonstrated.
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Teng, Hanwei, Shujian Li, Zheng Cao, Shuang Li, Changping Li e Tae Jo Ko. "Carbon Fiber Composites for Large-Scale Wind Turbine Blades: Applicability Study and Comprehensive Evaluation in China". Journal of Marine Science and Engineering 11, n. 3 (16 marzo 2023): 624. http://dx.doi.org/10.3390/jmse11030624.
Testo completoAbstract (sommario):
Wind energy is a type of clean energy that can address global energy shortages and environmental issues. Wind turbine blades are a critical component in capturing wind energy. Carbon fiber composites have been widely recognized for their excellent overall performance in large-scale wind turbine blades. However, in China, the wide application of carbon fiber composites in wind turbine blades still faces many problems and challenges. This paper examines the current state of carbon fiber composites for wind turbine blades and the geographical distribution characteristics of wind resources in China. The economic revenues from increasing the length of wind turbine blades in four typical wind farms, including offshore wind farms, are compared. Using a mathematical model, the energy efficiency of carbon fiber composites in the application of large wind turbine blades is evaluated from the aspects of cost, embedded energy, and carbon footprint. Further, the current relationship between supply and demand for the industrial structure of carbon fiber in China is revealed. The manufacturing technologies for carbon fiber composite wind turbine blades are analyzed, and corresponding countermeasures are proposed. Finally, the incentive policy for applying carbon fiber composites to wind turbine blades is explained, and the development prospects are explored. In this paper, the economics and energy efficiency of the application of carbon fiber composite materials in large wind turbine blades are analyzed and comprehensively evaluated by using mathematical models, which will provide a valuable reference for China’s wind turbine blade industry.
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Zha, Ruosi, e Kai Wang. "Numerical simulation of flow-induced noise generation and propagation of a floating offshore wind turbine with prescribed pitch motion". Journal of the Acoustical Society of America 154, n. 4_supplement (1 ottobre 2023): A283. http://dx.doi.org/10.1121/10.0023533.
Testo completoAbstract (sommario):
It is important to evaluate flow-induced noise emitted due to operations of floating offshore wind turbines since noise pollution can damage the environments of seabirds and aquatic species. This paper studies the aerodynamic and aeroacoustic performance of a laboratory three-blade wind turbine model with an airfoil profile of NREL S826. The wind turbine blade rotation motion is coupled with the prescribed pitch motion of the floating offshore wind power platform. The influence of prescribed pitch motions on the noise generated by wind turbine blades and noise propagation was discussed. Adopting the computational fluid dynamics (CFD) method, the aerodynamic noise field on a blade is simulated by the improved delayed detached eddy simulation (IDDES) model and Ffowcs Williams–Hawkings (FW-H) acoustic analogy. The overset grid technique is adopted to simulate the six degrees of freedom (DoFs) motions of the floating offshore wind turbine model. The sound source distributions on blades for noise generation are obtained, and the flow-induced noise propagation characteristics are analyzed. It is found that the influence of the pitch amplitude and frequency on the flow-induced noise field as well as the wake vortex characteristics should not be neglected.
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Zhou, Xingguo, Yankang Tian e Yi Qin. "IoT platform for offshore wind turbine blade structure health monitoring". MATEC Web of Conferences 401 (2024): 08012. http://dx.doi.org/10.1051/matecconf/202440108012.
Testo completoAbstract (sommario):
Wind energy, as renewable energy, is critical in targeting carbon neutrality or net zero emissions in order to address global climate change. Compared with onshore wind turbines, offshore wind turbines enjoy generally higher wind speed, thus producing more electric energy. However, the harsh marine environment, including high winds, wave-induced vibrations and and sea and rain corrosion and erosion, can lead to structural damage, reduced operational efficiency and increased maintenance cost. This paper presents a novel Internet of Things (IoT) platform for structural health monitoring (SHM) of the offshore wind turbine’s key component, the wind turbine blades. This research focuses on developing a comprehensive, real-time monitoring system that utilises advanced sensor networks, edge computing, and advanced predictive algorithms to strengthen on-time maintenance of turbine blades, while avoiding unnecessary and costly regular maintenance.
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Ma, Yong, Aiming Zhang, Lele Yang, Chao Hu e Yue Bai. "Investigation on Optimization Design of Offshore Wind Turbine Blades based on Particle Swarm Optimization". Energies 12, n. 10 (23 maggio 2019): 1972. http://dx.doi.org/10.3390/en12101972.
Testo completoAbstract (sommario):
Offshore wind power has become an important trend in global renewable energy development. Based on a particle swarm optimization (PSO) algorithm and FAST program, a time-domain coupled calculation model for a floating wind turbine is established, and a combined optimization design method for the wind turbine’s blade is developed in this paper. The influence of waves on the power of the floating wind turbine is studied in this paper. The results show that, with the increase of wave height, the power fluctuation of the wind turbine increases and the average power of the wind turbine decreases. With the increase of wave period, the power oscillation amplitude of the wind turbine increases, and the power of the wind turbine at equilibrium position decreases. The optimal design of the offshore floating wind turbine blade under different wind speeds is carried out. The results show that the optimum effect of the blades is more obvious at low and mid-low wind speeds than at rated wind speeds. Considering the actual wind direction distribution in the sea area, the maximum power of the wind turbine can be increased by 3.8% after weighted optimization, and the chord length and the twist angle of the blade are reduced.
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Song, Jian, Junying Chen, Yufei Wu e Lixiao Li. "Topology Optimization-Driven Design for Offshore Composite Wind Turbine Blades". Journal of Marine Science and Engineering 10, n. 10 (13 ottobre 2022): 1487. http://dx.doi.org/10.3390/jmse10101487.
Testo completoAbstract (sommario):
With the increase in wind turbine power, the size of the blades is significantly increasing to over 100 m. It is becoming more and more important to optimize the design for the internal layout of large-scale offshore composite wind turbine blades to meet the structural safety requirements while improving the blade power generation efficiency and achieving light weight. In this work, the full-scale internal layout of an NREL 5 MW offshore composite wind turbine blade is elaborately designed via the topology optimization method. The aerodynamic wind loads of the blades were first simulated based on the computational fluid dynamics. Afterwards, the variable density topology optimization method was adopted to perform the internal structure design of the blade. Then, the first and second generation multi-web internal layouts of the blade were reversely designed and evaluated in accordance with the stress level, maximum displacement of blade tip and fatigue life. In contrast with the reference blade, the overall weight of the optimized blade was reduced by 9.88% with the requirements of stress and fatigue life, indicating a better power efficiency. Finally, the vibration modal and full life cycle of the designed blade were analyzed. The design conception and new architecture could be useful for the improvement of advanced wind turbines.
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Méndez, B., X. Munduate e U. San Miguel. "Airfoil family design for large offshore wind turbine blades". Journal of Physics: Conference Series 524 (16 giugno 2014): 012022. http://dx.doi.org/10.1088/1742-6596/524/1/012022.
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Talbot, Jeremy, Qing Wang, Neil Brady e Roger Holden. "Offshore wind turbine blades measurement using Coherent Laser Radar". Measurement 79 (febbraio 2016): 53–65. http://dx.doi.org/10.1016/j.measurement.2015.10.030.
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Richards, Phillip W., D. Todd Griffth e Dewey H. Hodges. "Smart Loads Management for Damaged Offshore Wind Turbine Blades". Wind Engineering 39, n. 4 (agosto 2015): 419–36. http://dx.doi.org/10.1260/0309-524x.39.4.419.
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Li, Jing, Jianyun Chen e Xiaobo Chen. "Dynamic characteristics analysis of the offshore wind turbine blades". Journal of Marine Science and Application 10, n. 1 (marzo 2011): 82–87. http://dx.doi.org/10.1007/s11804-011-1045-6.
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Valaker, E. A., S. Armada e S. Wilson. "Droplet Erosion Protection Coatings for Offshore Wind Turbine Blades". Energy Procedia 80 (2015): 263–75. http://dx.doi.org/10.1016/j.egypro.2015.11.430.
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Dashtkar, Arash, Homayoun Hadavinia, M. Necip Sahinkaya, Neil A. Williams, Samireh Vahid, Fanya Ismail e Matthew Turner. "Rain erosion-resistant coatings for wind turbine blades: A review". Polymers and Polymer Composites 27, n. 8 (15 maggio 2019): 443–75. http://dx.doi.org/10.1177/0967391119848232.
Testo completoAbstract (sommario):
Wind blades are the most expensive parts of wind turbines made from fibre-reinforced polymer composites. The blades play a critical role on the energy production, but they are prone to damage like any other composite components. Leading edge (LE) erosion of the wind turbine blades is one of the common damages, causing a reduction in the annual energy production especially in offshore wind turbine farms. This erosion can be caused by rain, sand and flying solid particles. Coating the blade against erosion using appropriate materials can drastically reduce these losses and hence is of great interest. The sol–gel technique is a convenient method to manufacture thin film coatings, which can protect the blades against the rain erosion, while having negligible effect on the weight of the blades. This article provides an extensive review of the liquid erosion mechanism, water erosion testing procedures and the contributing factors to the erosion of the LE of wind turbine blades. Techniques for improving the erosion resistance of the LE using carbon nanotubes and graphene nano-additives are also discussed.
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Anderson, Benjamin, Pietro Bortolotti e Nick Johnson. "Development of an open-source segmented blade design tool". Journal of Physics: Conference Series 2265, n. 3 (1 maggio 2022): 032023. http://dx.doi.org/10.1088/1742-6596/2265/3/032023.
Testo completoAbstract (sommario):
Abstract As wind turbines continue to grow ever larger to reduce the cost of energy, their blades follow suit, with the largest commercial offshore blades extending past 100 m. Massive blades such as these raise key transportation and manufacturing challenges, especially for land-based turbines. Segmented blades are one solution and are garnering increased industry and research interest. In this work, a detailed mechanical joint model is integrated into the Wind-Plant Integrated System Design and Engineering Model (WISDEM®), which will facilitate future segmented blade research and optimization. WISDEM is used to design a wind turbine with 100-m segmented blades. This wind turbine design is compared to other machines with 100-m monolithic blades designed for rail-transportability. The designs are compared in terms of blade mass and cost, turbine capital cost, annual energy production, and levelized cost of energy, with monolithic designs being the lightest and most economical. However, this result may vary by wind plant location. A variety of segmentation joint types exist, and they will inevitably vary in parameters such as cost, spanwise location, and physical characteristics. This work examines the sensitivity of wind turbine design drivers and annual energy production to a variety of the aforementioned parameters, using the open-source wind turbine design codes OpenFAST and WISDEM, finding that joint mass, stiffness, and location can have significant effects on design drivers.
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Srilakshmi, Koganti, P. Aravindhababu e P. Ravi Babu. "A New Frequency for Offshore Wind-farm Based on Component Loss Calculation". International Journal of Applied Power Engineering (IJAPE) 7, n. 3 (1 dicembre 2018): 227. http://dx.doi.org/10.11591/ijape.v7.i3.pp227-234.
Testo completoAbstract (sommario):
<span lang="EN-IN">Offshore wind power plants are gaining importance in recent years, as there is adequate space available for its installation, high wind speed, no restriction on the size of turbine blades (no transportation and construction problem) and blades can be allowed to rotate at higher speed without any noise constraint, thereby increasing the rated power. However, the existing offshore wind farms face greater cost related challenges than those of onshore plants. The integration of offshore wind farm with onshore power grid is a complex issue. Feasible solutions for power transmission through cables from offshore wind farms to onshore are HVAC, line commutated HVDC and VSC-HVDC. This paper analyses the various schemes for integration of offshore wind farm with onshore power grid and suggests that LFAC with submarine cable operating at 0.7 Hz is an optimal choice in obtaining better performances. </span>
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Binsbergen, Diederik van, Amrit Verma, Amir Nejad e Jan Helsen. "Modeling of rain-induced erosion of wind turbine blades within an offshore wind cluster". Journal of Physics: Conference Series 2875, n. 1 (1 novembre 2024): 012040. http://dx.doi.org/10.1088/1742-6596/2875/1/012040.
Testo completoAbstract (sommario):
Abstract This study investigates the influence of wind turbine wakes on the incubation period of leading-edge erosion in offshore environments within an offshore wind cluster. The analysis is performed on a cluster of 250MW+ offshore wind farms mainly consisting of wind turbines with over 5MW rated power. The incubation time of the leading-edge erosion is determined for each turbine from wind-and-rain statistics, coating properties, and tuned analytical wake models. The wind speed, wind direction, and conditional probability of the rain are determined using 25 years of ERA5 reanalysis data. Droplet size distributions are derived from Best’s analytical distribution, which provides a probability distribution of the rain droplet size for a given rainfall intensity. For each wind turbine, the inflow speed and rotor speed are calculated using the TurboGaussian wake model. In addition, an analytical surface fatigue model is used to estimate the short-term erosion damage rates. By multiplying the short-term erosion damage rate with their respective join probabilities, equivalent damage is obtained the inverse of which will indicate the coating lifetime. The results indicate that variability in the coating lifetime across the wind farms can reach up to 35%. Notably, turbines that are predominantly positioned upstream are found to have the shortest coating lifetimes.
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Cui, Jiaping, Zhigang Cao, Pin Lyu, Huaiwu Peng, Quankun Li, Ruixian Ma e Yingming Liu. "Research on the Blades and Performance of Semi-Submersible Wind Turbines with Different Capacities". Energies 17, n. 13 (2 luglio 2024): 3259. http://dx.doi.org/10.3390/en17133259.
Testo completoAbstract (sommario):
With the gradual increase in the maturity of wind energy technology, floating offshore wind turbines have progressively moved from small-capacity demonstrations to large-capacity commercial applications. As a direct component of wind turbines used to capture wind energy, an increase in the blade length directly leads to an increase in blade flexibility and a decrease in aerodynamic performance. Furthermore, if the floater has an additional six degrees of freedom, the movement and load of the blade under the combined action of wind and waves are more complicated. In this work, two types of semi-submersible wind turbines with different capacities are used as the research objects, and the load and motion characteristics of the blades of these floating offshore wind turbines are studied. Through the analysis of the simulation data, the following conclusions are drawn: with the increase in the capacity of the wind turbine, the flexible deformation of the blade increases, the movement range of the blade tip becomes larger, the blade root load increases, and the power fluctuation is more obvious. Compared with the bottom-fixed wind turbine, the flexible blade deformation of the floating offshore wind turbine is smaller; however, the blade root load is more dispersed, and the power output is more unstable and lower.
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Recalde-Camacho, L., W. Leithead, L. Morgan e A. Kazemi Amiri. "Controller design for the X-Rotor offshore wind turbine concept". Journal of Physics: Conference Series 2767, n. 3 (1 giugno 2024): 032050. http://dx.doi.org/10.1088/1742-6596/2767/3/032050.
Testo completoAbstract (sommario):
Abstract This paper explores the design of a full envelope speed controller to operate the X-Rotor Offshore Wind Turbine. The X-Rotor is a heavily modified V-rotor vertical axis wind turbine, in which the primary rotor has conventional blades angled both up and down from the ends of a relatively short and stiff cross-arm. The upper half employs full span blade pitching for speed regulation and the lower half is aimed at reducing overturning moments on the main bearing and provides power take-off through compact secondary horizontal axis turbines mounted at the tip of the lower blades. The operational strategy is somewhat similar to that of a variable speed pitch regulated horizontal axis wind turbine, however it differs in the following aspects: the way aerodynamic torque is balanced across the operating envelope, the adjustment of equilibrium operating points at below rated operation, the relationship of aerodynamic torque on the primary rotor to pitch angle, and the operation of the secondary rotors to increase energy capture. These aspects increase the complexity of the control strategy but also ease the controller requirements. The developed controller is tested on a turbine model with sufficient complexity to model the essential dynamic properties of the turbine concept.
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McGugan, M., G. Pereira, B. F. Sørensen, H. Toftegaard e K. Branner. "Damage tolerance and structural monitoring for wind turbine blades". Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 373, n. 2035 (28 febbraio 2015): 20140077. http://dx.doi.org/10.1098/rsta.2014.0077.
Testo completoAbstract (sommario):
The paper proposes a methodology for reliable design and maintenance of wind turbine rotor blades using a condition monitoring approach and a damage tolerance index coupling the material and structure. By improving the understanding of material properties that control damage propagation it will be possible to combine damage tolerant structural design, monitoring systems, inspection techniques and modelling to manage the life cycle of the structures. This will allow an efficient operation of the wind turbine in terms of load alleviation, limited maintenance and repair leading to a more effective exploitation of offshore wind.
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Khoury, Boutros, Vicenç Puig e Fatiha Nejjari. "Model-based Prognosis Approach using a Zonotopic Kalman Filter with Application to a Wind Turbine". PHM Society European Conference 5, n. 1 (22 luglio 2020): 9. http://dx.doi.org/10.36001/phme.2020.v5i1.1258.
Testo completoAbstract (sommario):
Wind turbines generally operate under adverse conditions making them prone to relatively high failure rates. Due to the direct exposure of the blades to dynamic and cyclic loads of wind, the rotor and the blades unsurprisingly represent the most common major component damages of a wind turbine system, which is especially enhanced when located offshore.
This paper presents a new model-based prognosis procedure based on a zonotopic Kalman filter (ZKF), which combines a physical model with observed data to assess the system degradation. Using this information and the model of the system, the end of life (EOL) and the remaining useful life (RUL) with its uncertainty can be predicted. The proposed prognostic method is applied to monitor the state of health of a wind turbine system specifically, its blades. The remaining useful life prediction will help in scheduling optimal maintenance and reducing the cost caused by wind turbine damage and unplanned shutdown.
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Ning, Fang-Shii, Kuang-Chang Pien, Wei-Jie Liou e Tsung-Chi Cheng. "Site Selection for Offshore Wind Power Farms with Natural Disaster Risk Assessment: A Case Study of the Waters off Taiwan’s West Coast". Energies 17, n. 11 (3 giugno 2024): 2711. http://dx.doi.org/10.3390/en17112711.
Testo completoAbstract (sommario):
This research examines the risk of natural disasters for offshore wind turbines together with their potential wind energy capacity to help the site selection of offshore wind power farms. Through evaluations of expert questionnaires, we use the fuzzy analytic hierarchy process to weight how natural disasters damage the sub-assemblies of an offshore wind turbine, then obtain the natural disaster risk assessment model, and finally utilize ArcGIS Pro 3.2 to map the potential wind farm sites for the waters off Taiwan’s west coast. We identify that typhoons are the most threatening type of disaster to generators, rotor blades, and rotor hubs; earthquakes are the most threatening to towers; and lightning is the most threatening to transformers. For the whole wind turbine, wind is ironically the most threatening natural disaster, followed by lightning, sea waves, and then earthquakes. Lastly, we examine the results by overlapping the offshore wind farms developed and planned in Taiwan, which coincide with locations in relatively low risk and high wind speed areas.
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Cai, Xin, Yazhou Wang, Bofeng Xu e Junheng Feng. "Performance and Effect of Load Mitigation of a Trailing-Edge Flap in a Large-Scale Offshore Wind Turbine". Journal of Marine Science and Engineering 8, n. 2 (23 gennaio 2020): 72. http://dx.doi.org/10.3390/jmse8020072.
Testo completoAbstract (sommario):
As a result of the large-scale trend of offshore wind turbines, wind shear and turbulent wind conditions cause significant fluctuations of the wind turbine’s torque and thrust, which significantly affect the service life of the wind turbine gearbox and the power output stability. The use of a trailing-edge flap is proposed as a supplement to the pitch control to mitigate the load fluctuations of large-scale offshore wind turbines. A wind turbine rotor model with a trailing-edge flap is established by using the free vortex wake (FVW) model. The effects of the deflection angle of the trailing-edge flap on the load distribution of the blades and wake flow field of the offshore wind turbine are analyzed. The wind turbine load response under the control of the trailing-edge flap is obtained by simulating shear wind and turbulent wind conditions. The results show that a better control effect can be achieved in the high wind speed condition because the average angle of attack of the blade profile is small. The trailing-edge flap significantly changes the load distribution of the blade and the wake field and mitigates the low-frequency torque and thrust fluctuations of the turbine rotor under the action of wind shear and turbulent wind.
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Bošnjaković, Mladen, Marko Katinić, Robert Santa e Dejan Marić. "Wind Turbine Technology Trends". Applied Sciences 12, n. 17 (29 agosto 2022): 8653. http://dx.doi.org/10.3390/app12178653.
Testo completoAbstract (sommario):
The rise in prices of traditional energy sources, the high dependence of many countries on their import, and the associated need for security of supply have led to large investments in new capacity of wind power plants. Although wind power generation is a mature technology and levelized cost of electricity low, there is still room for its improvement. A review of available literature has indicated that wind turbine development in the coming decade will be based on upscaling wind turbines and minor design improvements. These include further improvements in rotor blade aerodynamics, active control of the rotor blade rotation system, and aerodynamic brakes that will lead to increased power generation efficiency. Improvements in system maintenance and early diagnosis of transmission and power-related faults and blade surface damage will reduce wind turbine downtime and increase system reliability and availability. The manufacture of wind turbines with larger dimensions presents problems of transportation and assembly, which are being addressed by manufacturing the blades from segments. Numerical analysis is increasingly being used both in wind turbine efficiency analysis and in stress and vibration analysis. Direct drive is becoming more competitive with traditional power transmission through a gearbox. The trend in offshore wind farms is to increase the size of wind turbines and to place them farther from the coast and in deeper water, which requires new forms of floating foundations. Due to the different work requirements and more difficult conditions of the marine environment, optimization methods for the construction of offshore substructures are currently being developed. There are plans to use 66-kV cables for power transmission from offshore wind farms instead of the current 33-kV cables. Offshore wind farms can play an important role in the transition to a hydrogen economy. In this context, significant capacity is planned for the production of “green” hydrogen by electrolysis from water. First-generation wind turbines are nearing the end of their service life, so strategies are being developed to repower them, extend their life or dismantle and recycle them.
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Dong, X. H., T. J. Yuan e R. H. Ma. "Mechanical Analysis of Fatigue Damages on Offshore Wind Turbine Blades". Journal of Applied Sciences 13, n. 10 (1 maggio 2013): 1895–900. http://dx.doi.org/10.3923/jas.2013.1895.1900.
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Boudounit, Hicham, Mostapha Tarfaoui e Dennoun Saifaoui. "Modal analysis for optimal design of offshore wind turbine blades". Materials Today: Proceedings 30 (2020): 998–1004. http://dx.doi.org/10.1016/j.matpr.2020.04.373.
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Caboni, Marco, Henk M. Slot, Gerben Bergman, Dennis A. J. Wouters e Harald J. Van Der Mijle Meijer. "Evaluation of wind turbine blades’ rain-induced leading edge erosion using rainfall measurements at offshore, coastal and onshore locations in the Netherlands". Journal of Physics: Conference Series 2767, n. 6 (1 giugno 2024): 062003. http://dx.doi.org/10.1088/1742-6596/2767/6/062003.
Testo completoAbstract (sommario):
Abstract The impingement of rain drops on wind turbine blades determines leading edge erosion (LEE) which is a factor driving high maintenance costs. In order to better quantify rain-induced LEE, we carried out detailed rainfall measurements, by means of disdrometers, in conjunction with wind speed measurements. Measurements were performed at three different Dutch sites, encompassing an offshore, a coastal and an onshore location. Based on rainfall and wind speed measurements, and assuming a virtual 15 MW wind turbine, we estimated the blade’s LEE using a fatigue-based model. Developed by means of different published rotating arm erosion data, our fatigue model relates the measured rainfall characteristics to the LEE incubation period, here assumed as the leading edge protection (LEP) system’s end of life. Assuming a polyurethane LEP system, results indicate that the blades’ incubation period is around 3.9 years at the offshore location, 6.6 years at the coastal location and 8.3 years at the onshore location. These results are connected to the higher wind speeds during rainfalls, and higher occurrences of very intense rainy events which, according to the measurements, progressively occur at the onshore, coastal and offshore locations.
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Wu, Zonghao, Kai Wang, Tianyu Jie e Xiaodi Wu. "Coupled Dynamic Characteristics of a Spar-Type Offshore Floating Two-Bladed Wind Turbine with a Flexible Hub Connection". Journal of Marine Science and Engineering 12, n. 4 (25 marzo 2024): 547. http://dx.doi.org/10.3390/jmse12040547.
Testo completoAbstract (sommario):
To reduce manufacturing, transportation, lifting and maintenance costs of increasingly larger and larger floating wind turbines, a Spar-type floating two-bladed wind turbine based on the 5 MW OC3-Hywind floating wind turbine model from the National Renewable Energy Laboratory (NREL) is studied in this paper. The two-bladed wind turbine can cause serious problems with large dynamic loads, so a flexible hub connection was introduced between the hub mount and nacelle carrier to alleviate the dynamic effect. The paper focuses on studying the dynamic responses of the proposed Spar-type floating two-bladed wind turbine with a flexible hub connection at rated and extreme environmental conditions. Fully coupled time-domain simulations are carried out by integrating aerodynamic loads on blades, hydrodynamic loads on the spar, structural dynamics of the tower, blades and mooring lines, control system and flexible hub connection. The analysis results show that the application of a flexible hub connection between the hub mount and nacelle carrier can make a contribution to enable the Spar-type floating two-bladed wind turbine to effectively dampen the motion of the floating platform, while significantly reducing the tower load and blade deflection.
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Korczewski, Zbigniew, e Jacek Rudnicki. "Active Diagnostic Experimentation on Wind Turbine Blades with Vibration Measurements and Analysis". Polish Maritime Research 31, n. 3 (21 agosto 2024): 126–34. http://dx.doi.org/10.2478/pomr-2024-0042.
Testo completoAbstract (sommario):
Abstract This paper deals with the key operational problems of wind turbosets, especially offshore, where vibrations are generated by rotor blades, as a consequence of erosive wear or icing. The primary causes of the imbalance of wind turbine rotors have been characterised, the observable symptoms of which include various forms of vibrations, transmitted from the turbine wheel to the bearing nodes of the power train components. Their identification was the result of an active diagnostic experiment, which actually entered the aerodynamic-mass imbalance of a turbine rotor into a wind power train, built as a small scale model. The recording of the observed monitoring parameters (vibration, aerodynamic, mechanical and electrical) made it possible to determine a set of symptoms (syndrome) of the deteriorated (entered) dynamic state of the entire wind turboset. This provides the basis for positive verification of the assumed concept and methodology of diagnostic testing, the constructed laboratory station and the measuring equipment used. For this reason, testing continued, taking into account the known and recognisable faults that most often occur during the operation of offshore wind turbosets. Transferring the results of this type of model research to full-size, real objects makes it possible to detect secondary (fatigue) damage to the elements transmitting torque from the wind turbine rotor to the generator early, especially the thrust bearings or gear wheel teeth.
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Morăraș, Ciprian Ionuț, Viorel Goanță, Dorin Husaru, Bogdan Istrate, Paul Doru Bârsănescu e Corneliu Munteanu. "Analysis of the Effect of Fiber Orientation on Mechanical and Elastic Characteristics at Axial Stresses of GFRP Used in Wind Turbine Blades". Polymers 15, n. 4 (9 febbraio 2023): 861. http://dx.doi.org/10.3390/polym15040861.
Testo completoAbstract (sommario):
Due to its physical and mechanical properties, glass-fiber-reinforced polymer (GFRP) is utilized in wind turbine blades. The loads given to the blades of wind turbines, particularly those operating offshore, are relatively significant. In addition to the typical static stresses, there are also large dynamic stresses, which are mostly induced by wind-direction changes. When the maximum stresses resulting from fatigue loading change direction, the reinforcing directions of the material used to manufacture the wind turbine blades must also be considered. In this study, sandwich-reinforced GFRP materials were subjected to tensile testing in three directions. The parameters of the stress–strain curve were identified and identified based on the three orientations in which samples were cut from the original plate. Strain gauge sensors were utilized to establish the three-dimensional elasticity of a material. After a fracture was created by tensile stress, SEM images were taken to highlight the fracture’s characteristics. Using finite element analyses, the stress–strain directions were determined. In accordance to the three orientations and the various reinforcements used, it was established that the wind turbine blades are operational.
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Boudounit, Hicham, Mostapha Tarfaoui, Dennoun Saifaoui e Mourad Nachtane. "Structural analysis of offshore wind turbine blades using finite element method". Wind Engineering 44, n. 2 (23 maggio 2019): 168–80. http://dx.doi.org/10.1177/0309524x19849830.
Testo completoAbstract (sommario):
Wind energy is one among the most promising renewable energy sources, and hence there is fast growth of wind energy farm implantation over the last decade, which is expected to be even faster in the coming years. Wind turbine blades are complex structures considering the different scientific fields involved in their study. Indeed, the study of blade performance involves fluid mechanics (aerodynamic study), solids mechanics (the nature of materials, the type of solicitations …), and the fluid coupling structure (IFS). The scope of the present work is to investigate the mechanical performances and structural integrity of a large offshore wind turbine blade under critical loads using blade element momentum. The resulting pressure was applied to the blade by the use of a user subroutine “DLOAD” implemented in ABAQUS finite element analysis software. The main objective is to identify and predict the zones which are sensitive to damage and failure as well as to evaluate the potential of composite materials (carbon fiber and glass fiber) and their effect on reduction of rotor’s weight, as well as the increase of resistance to wear, and stiffness.