Journal articles on the topic 'Turbine blade vibration'
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1
Loss, Theresa, and Alexander Bergmann. "Vibration-Based Fingerprint Algorithm for Structural Health Monitoring of Wind Turbine Blades." Applied Sciences 11, no. 9 (May 10, 2021): 4294. http://dx.doi.org/10.3390/app11094294.
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Monitoring the structural health of wind turbine blades is essential to increase energy capture and operational safety of turbines, and therewith enhance competitiveness of wind energy. With the current trends of designing blades ever longer, detailed knowledge of the vibrational characteristics at any point along the blade is desirable. In our approach, we monitor vibrations during operation of the turbine by wirelessly measuring accelerations on the outside of the blades. We propose an algorithm to extract so-called vibration-based fingerprints from those measurements, i.e., dominant vibrations such as eigenfrequencies and narrow-band noise. These fingerprints can then be used for subsequent analysis and visualisation, e.g., for comparing fingerprints across several sensor positions and for identifying vibrations as global or local properties. In this study, data were collected by sensors on two test turbines and fingerprints were successfully extracted for vibrations with both low and high operational variability. An analysis of sensors on the same blade indicates that fingerprints deviate for positions at large radial distance or at different blade sides and, hence, an evaluation with larger datasets of sensors at different positions is promising. In addition, the results show that distributed measurements on the blades are needed to gain a detailed understanding of blade vibrations and thereby reduce loads, increase energy harvesting and improve future blade design. In doing so, our method provides a tool for analysing vibrations with relation to environmental and operational variability in a comprehensive manner.
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Ando, Takashi. "Pulsation and Vibration Measurement on Stator Side for Turbocharger Turbine Blade Vibration Monitoring." International Journal of Turbomachinery, Propulsion and Power 5, no. 2 (May 25, 2020): 11. http://dx.doi.org/10.3390/ijtpp5020011.
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Mechanically robust turbine design with respect to blade vibration is challenging when dealing with nozzle-ring fouling and wear. Especially for engines operating with heavy fuel oil (HFO), the nozzle rings of the turbocharger turbines are prone to severe degradation in terms of contamination with unburned fuel deposits. This contamination will lead to an increased excitation of blade resonances in comparison to the nominal design. Due to the statistical character of contamination, long-term monitoring of blade vibration amplitudes would be beneficial. In the harsh environment of HFO operation, however, conventional blade vibration measurement techniques, such as those using strain gauges or blade tip timing, cannot work reliably for a long period. Thus, the objective of this research is to develop a method that enables the monitoring of turbine blades using pulsation or vibration sensors installed on the stator side. Almost a dozen turbines, both radial and axial, have been examined in order to determine a proper measurement chain/position and analytical method. Even though the challenges specific to the turbocharger turbine application—that high-frequency (up to 50 kHz) acoustic radiation from turbine blades has to be detected by a sensor on the stator side—were demanding, in the course of the investigations several clear examples of turbine blades engine-order resonance detection were gathered. Finally, the proposed method has been tested successfully in a power plant for over one year.
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Reinhardt, A. K., J. R. Kadambi, and R. D. Quinn. "Laser Vibrometry Measurements of Rotating Blade Vibrations." Journal of Engineering for Gas Turbines and Power 117, no. 3 (July 1, 1995): 484–88. http://dx.doi.org/10.1115/1.2814121.
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One of the most important design factors in modern turbomachinery is the vibration of turbomachinery blading. There is a need for developing an in-service, noncontacting, noninterfering method for the measurement and monitoring of gas turbine, jet engine, and steam turbine blade vibrations and stresses. Such a technique would also be useful for monitoring rotating helicopter blades. In the power generation industry, blade failures can result in millions of dollars of downtime. The measurement of blade vibrations and dynamic stresses is an important guide for preventive maintenance, which can be a major contributor to the availability of steam turbine, gas turbine, and helicopter operations. An experiment is designed to verify the feasibility of such a vibration monitoring system using the reference beam on-axis laser-Doppler technique. The experimental setup consists of two flat, cantilever blades mounted on a hub attached to the shaft of a dc motor. The motor rests on a linear bearing permitting motion only in the direction of the motor shaft. The motor and blade assembly is then excited via an electrodynamic shaker at the first natural frequency of the blades. The resulting blade vibration is then detected using a laser vibrometer. The vibration frequencies and amplitudes of the two rotating blades are successfully measured.
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Gantasala, Sudhakar, Narges Tabatabaei, Michel Cervantes, and Jan-Olov Aidanpää. "Numerical Investigation of the Aeroelastic Behavior of a Wind Turbine with Iced Blades." Energies 12, no. 12 (June 24, 2019): 2422. http://dx.doi.org/10.3390/en12122422.
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Wind turbines installed in cold-climate regions are prone to the risks of ice accumulation which affects their aeroelastic behavior. The studies carried out on this topic so far considered icing in a few sections of the blade, mostly located in the outer part of the blade, and their influence on the loads and power production of the turbine are only analyzed. The knowledge about the influence of icing in different locations of the blade and asymmetrical icing of the blades on loads, power, and vibration behavior of the turbine is still not matured. To improve this knowledge, multiple simulation cases are needed to run with different ice accumulations on the blade considering structural and aerodynamic property changes due to ice. Such simulations can be easily run by automating the ice shape creation on aerofoil sections and two-dimensional (2-D) Computational Fluid Dynamics (CFD) analysis of those sections. The current work proposes such methodology and it is illustrated on the National Renewable Energy Laboratory (NREL) 5 MW baseline wind turbine model. The influence of symmetrical icing in different locations of the blade and asymmetrical icing of the blade assembly is analyzed on the turbine’s dynamic behavior using the aeroelastic computer-aided engineering tool FAST. The outer third of the blade produces about 50% of the turbine’s total power and severe icing in this part of the blade reduces power output and aeroelastic damping of the blade’s flapwise vibration modes. The increase in blade mass due to ice reduces its natural frequencies which can be extracted from the vibration responses of the turbine operating under turbulent wind conditions. Symmetrical icing of the blades reduces loads acting on the turbine components, whereas asymmetrical icing of the blades induces loads and vibrations in the tower, hub, and nacelle assembly at a frequency synchronous to rotational speed of the turbine.
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Biglari, Hamed, and Vahid Fakhari. "Edgewise vibration reduction of small size wind turbine blades using shunt damping." Journal of Vibration and Control 26, no. 3-4 (September 24, 2019): 186–99. http://dx.doi.org/10.1177/1077546319877706.
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Edgewise vibration in wind turbine blades is one of the important factors that results in reducing the performance of wind turbines. Therefore, control or reduction of the mentioned vibrations can be of great help in increasing the efficiency of wind turbines. In this paper, the shunt damping method is proposed to reduce the edgewise blade vibration of horizontal axis wind turbines. For this purpose, partial differential equations governing dynamics of the system are derived using the Lagrange method. These equations are completely nonlinear and linearization is not performed to avoid possible errors in the analysis. In order to evaluate the effectiveness of the proposed shunt damping method in vibration reduction of the wind turbine blade, obtained results by applying shunt damping method are compared with corresponding results obtained by employing a conventional method known as a tuned mass damper (TMD). For better comparison, by considering proper cost functions, the shunt damper and TMD parameters are optimized using a genetic algorithm. Finally, the effectiveness of optimized shunt damper in vibration reduction of the blade is compared with optimized TMD by presenting simulation results.
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Zhang, Qinglei, Haoyang Wang, Jiyun Qin, and Jianguo Duan. "Study on the collision dynamics of integral shroud blade for high-pressure turbine in different integral shroud clearance distance." Noise & Vibration Worldwide 52, no. 7-8 (March 12, 2021): 200–211. http://dx.doi.org/10.1177/0957456521999874.
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In steam turbine, turbine blades are prone to vibrate during operation, resulting in steam turbine accidents. The most common method for reducing the vibration of steam turbine blades is to design an integral shroud for blade which is termed as integral shroud blade. Most previous studies simplified straight integral blades into cantilever beam and used harmonic response analysis method to simulate the vibration response of blades. This method is suitable for simulating straight blade vibration under harmonic force conditions. For twisted blades, accurate results are hard to acquire and the specific collision process cannot be simulated. In order to observe the collision process on a microscopic scale and explore its collision damping mechanism, this study evaluated the collision process of twisted blades with different integral shroud clearance distance based on LS-DYNA software. The collision process for a two-blade system and a three-blade system with integral shroud clearance distance from 0.1 mm to 0.5 mm has been simulated. The results indicated that integral shroud clearance distance have opposite vibration damping effect when the blade under the condition of forced vibration and free vibration. For the two-blade system, the optimal integral shroud clearance distance is 0.4 mm for forced vibration condition and 0.1 mm for free vibration condition. For the three-blade system, the optimal integral shroud clearance distance is 0.1 mm for forced vibration condition and 0.5 mm for free vibration condition.
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Rzadkowski, Romuald, Leszek Kubitz, Michał Maziarz, Pawel Troka, Krzysztof Dominiczak, and Ryszard Szczepanik. "Tip-Timing Measurements and Numerical Analysis of Last-Stage Steam Turbine Mistuned Bladed Disc During Run-Down." Journal of Vibration Engineering & Technologies 8, no. 3 (October 25, 2019): 409–15. http://dx.doi.org/10.1007/s42417-019-00185-2.
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Abstract Background This paper presents the experimental and numerical studies of last-stage low-pressure (LP) mistuned steam turbine bladed discs during run-down. Methods The natural frequencies and mode shapes of the turbine bladed disc were calculated using an FE model. The influence of the shaft on the modal properties, such as natural frequencies and mode shapes, was considered. The tip-timing method was used to find the mistuned bladed disc modes and frequencies. Conclusions The experimental results from the tip-timing analysis show that the mistuning in combination with shaft coupling suppresses pure nodal diameter type blade vibrations associated with the fundamental mode shape of a cantilevered blade. Vibration modes emerge when even a single blade is vibrating due to the well-known mode localization caused by mistuning. The numerical results confirm this.
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Liska, Jindrich, Vojtech Vasicek, and Jan Jakl. "A Novel Method of Impeller Blade Monitoring Using Shaft Vibration Signal Processing." Sensors 22, no. 13 (June 29, 2022): 4932. http://dx.doi.org/10.3390/s22134932.
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The monitoring of impeller blade vibrations is an important task in the diagnosis of turbomachinery, especially in terms of steam turbines. Early detection of potential faults is the key to avoid the risk of turbine unexpected outages and to minimize profit loss. One of the ways to achieve this is long-term monitoring. However, existing monitoring systems for impeller blade long-term monitoring are quite expensive and also require special sensors to be installed. It is even common that the impeller blades are not monitored at all. In recent years, the authors of this paper developed a new method of impeller blade monitoring that is based on relative shaft vibration signal measurement and analysis. In this case, sensors that are already standardly installed in the bearing pedestal are used. This is a significant change in the accessibility of blade monitoring for a steam turbine operator in terms of expenditures. This article describes the developed algorithm for the relative shaft vibration signal analysis that is designed to run in a long-term perspective as a part of a remote monitoring system to track the natural blade frequency and its amplitude automatically.
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Rani, Pooja, and Atul Kumar Agrawal. "Natural Frequency Evaluation of Low-Pressure Stage Blade of a 210 MW Steam Turbine." IOP Conference Series: Materials Science and Engineering 1248, no. 1 (July 1, 2022): 012032. http://dx.doi.org/10.1088/1757-899x/1248/1/012032.
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Abstract Steam turbines rely heavily on the performance and reliability of their rotor blades. When a steam turbine blade fails, it can pose a risk to workers' life, need expensive repairs, and cause income losses. The failure mechanism differs from case to case and is typically quite complex. The last stage turbine blades are very long and rotate at high speed. In extreme dynamic loads, these big blades are the most susceptible to failure. So, the dynamic behaviour of the last stage steam turbine blade is of great importance and analysed by numerical simulation in this work. Mode shapes at natural frequencies of the blade at stationary condition and at different speeds of rotation are determined. A Campbell diagram is used to forecast the expected operational conditions that may result in blade resonant vibration.
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Rogge, Timo, Ricarda Berger, Linus Pohle, Raimund Rolfes, and Jörg Wallaschek. "Efficient structural analysis of gas turbine blades." Aircraft Engineering and Aerospace Technology 90, no. 9 (November 14, 2018): 1305–16. http://dx.doi.org/10.1108/aeat-05-2016-0085.
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Purpose The purpose of this study a fast procedure for the structural analysis of gas turbine blades in aircraft engines. In this connection, investigations on the behavior of gas turbine blades concentrate on the analysis and evaluation of starting dynamics and fatigue strength. Besides, the influence of structural mistuning on the vibration characteristics of the single blade is analyzed and discussed. Design/methodology/approach A basic computation cycle is generated from a flight profile to describe the operating history of the gas turbine blade properly. Within an approximation approach for high-frequency vibrations, maximum vibration amplitudes are computed by superposition of stationary frequency responses by means of weighting functions. In addition, a two-way coupling approach determines the influence of structural mistuning on the vibration of a single blade. Fatigue strength of gas turbine blades is analyzed with a semi-analytical approach. The progressive damage analysis is based on MINER’s damage accumulation assuming a quasi-stable behavior of the structure. Findings The application to a gas turbine blade shows the computational capabilities of the approach presented. Structural characteristics are obtained by robust and stable computations using a detailed finite element model considering different load conditions. A high quality of results is realized while reducing the numerical costs significantly. Research limitations/implications The method used for analyzing the starting dynamics is based on the assumption of a quasi-static state. For structures with a sufficiently high stiffness, such as the gas turbine blades in the present work, this procedure is justified. The fatigue damage approach relies on the existence of a quasi-stable cyclic stress condition, which in general occurs for isotropic materials, as is the case for gas turbine blades. Practical implications Owing to the use of efficient analysis methods, a fast evaluation of the gas turbine blade within a stochastic analysis is feasible. Originality/value The fast numerical methods and the use of the full finite element model enable performing a structural analysis of any blade structure with a high quality of results.
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Hoznedl, Michal, Tereza Dadáková, and Jindřich Bém. "Flow and Vibration in the Small Steam Turbine Last Stage." MATEC Web of Conferences 369 (2022): 02001. http://dx.doi.org/10.1051/matecconf/202236902001.
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The paper deals with evaluation of experimental data obtained from the real-size 30 MW output Waste to Energy steam turbine. For many turbine regimes pressures in the last stage area were obtained. At the same time amplitudes of blade tips vibrations were measured of last rotor blades using the blade tip timing system and axial velocity of the steam at the last stage outlet. The obtained data are mutually correlated and relations are analysed between increased vibration values and pressure ratios at the last stage. Increased tip vibrations occur mainly in the area when the pressure ratio over the last blade tip and root is higher than one. In this case there is no expansion, but compression in the last stage of the turbine. The presented results contribute to understanding of processes in the last stage of the steam turbine, mainly for those regimes of turbine operation when its output is lower than 20 % of the nominal output, e.g. during the island regime.
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Pešek, Ludĕk, Ladislav Půst, Vítĕzslav Bula, and Jan Cibulka. "Application of Piezofilms for Excitation and Active Damping of Blade Flexural Vibration." Archives of Acoustics 40, no. 1 (March 1, 2015): 59–69. http://dx.doi.org/10.1515/aoa-2015-0008.
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Abstract The steam turbine blades of low pressure stages are endangerd by the high-cyclic fatigue due to the combined loading of dynamic stresses by the steam time-variant pressure and the pre-stress from centrifugal forces. Therefore, the importance of their experimental dynamic analysis in the design stage is critical. For laboratory tests of the blades, the piezo actuators placed on the blades, unlike electromagnets placed in the stationary space, give a possibility to excite the flexural vibration of the blades within the bladed disk by time continuous forces independently of the rotor revolutions. In addition, the piezo actuators can be also used to control the vibrations of the blade. Therefore, several dynamic experiments of the clamped model blade equipped with PVDF films were performed for the force description of the piezo foils and their behavior as actuators of the blade vibration. The numerical beam models were used for numerical analysis of the vibration suppression effects both by additional parametric excitation and by active damping. The optimal phase shift of piezo actuator voltage supply was ascertained both for amplitude amplification and suppression. The results contribute to the knowledge of the actuation and active damping of blade vibration by the piezo elements
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Cornelius, Charles C. "Turbine blade vibration dampening." Journal of the Acoustical Society of America 103, no. 3 (March 1998): 1245. http://dx.doi.org/10.1121/1.423186.
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Liska, Jindrich, Jan Jakl, and Vojtech Vasicek. "Rotating blades monitoring using standard turbine instrumentation." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 233, no. 23-24 (November 13, 2019): 7447–58. http://dx.doi.org/10.1177/0954406219889084.
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Ensuring the reliability of the steam turbine is fundamental task for its proper operation. Early detection of any failure avoids material and financial losses. A very important task in turbomachinery diagnostics is monitoring of rotating blades vibration, especially in terms of the last stages of low-pressure turbine parts, where, in general, the vibration can reach the important level due the blades length. The commonly used methods are based on stress evaluation using strain gauges or on the non-contact measurement of blade tips – blade tip-timing (BTT) method. Rising demand for low-cost monitoring systems suitable for blade monitoring has led to development of a new approach based on signal processing of standard turbine instrumentation. The symptoms of blade vibration could be also visible in signals from relative shaft vibration (SV) sensors, which are standardly installed in turbine journal bearings. This paper illustrates the principles and possibilities of the approach based on processing of SV signals for monitoring of actual state of rotating blades. Finally, the comparison of parallel measurements using SV and BTT in operation of steam turbine reveals the properties and advantages of both methods.
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Wagner, L. F., and J. H. Griffin. "Blade Vibration With Nonlinear Tip Constraint: Model Development." Journal of Turbomachinery 112, no. 4 (October 1, 1990): 778–85. http://dx.doi.org/10.1115/1.2927721.
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Turbine blades having integrally machined tip shrouds, with associated gaps between adjacent shrouds, often exhibit unusual vibratory responses with significant differences between the amplitudes and frequencies of individual blades on the same stage. These differences result from unavoidable variations in the shroud gaps causing, for large enough excitation, nonlinear constraint at the blade tips which varies from blade to blade. This study shows that the blade stresses cannot be adequately represented by the type of single-degree-of-freedom models that are often used for dynamic impact studies, but require the participation of higher frequency beam-type modes. The extension of the resulting beam model to multi-degree-of-freedom systems will allow the study of the “gap mistuning” phenomenon for practical bladed disks.
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Bolu, Gabriel, Gareth Pierce, Anthony Gachagan, Tim Barden, and Gerald Harvey. "Investigations into the Vibrational Response of an Aero-Engine Turbine Blade under Thermosonic Excitation." Key Engineering Materials 518 (July 2012): 184–92. http://dx.doi.org/10.4028/www.scientific.net/kem.518.184.
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Thermosonics is a rapid and potentially cost-saving non-destructive testing (NDT) screening technique that can be applied to the identification of cracks in high pressure compressor turbine blades in turbofan engines. The reliability of the thermosonic technique is not well established for inspecting these complex components; in particular the vibrational energy generated within a component during a thermosonic test is often highly non-uniform, leading to the possibility of missing critical defects. The aim of this study was to develop a methodology, using a combination of vibration measurements and finite element analysis (FEA), to model the vibrational energy within a turbine blade in a typical thermosonic inspection scenario. Using a laser vibrometer, the steady-state vibration response (i.e. frequency response) at several locations on a blade was measured and used to identify the prominent peaks in the frequency spectra. These were then used to generate an excitation function for the finite element modelling approach. Acceptable correlation between the measured and simulated vibration response at a number of specific locations on the blade allowed the forcing function to simulate the vibration response across the whole blade. Finally, the predicted displacement field was used to determine the vibrational energy at every point on the blade which was mapped onto a CAD representation of the blade, thereby highlighting areas on the blade that were below the defect detection threshold.
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Malkin, Evgeny. "Natural Vibration Frequency Definition Of Turbine Blades." E3S Web of Conferences 221 (2020): 03007. http://dx.doi.org/10.1051/e3sconf/202022103007.
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A turbine compressor package is used for pipeline gas transmission. When operating, compressor turbine blades develop vibration, which increases the number of dynamic stress cycles and results in the blade failure. The present study aims to determine the frequency of natural blade vibration and to consider it in the context of the blade repair process. In the first stage of the study, an oscillating contour is developed to generate standing oscillation wave which characteristics are used as experimental data. To process those data, a mathematical model is developed to calculate the blade resonant frequency. Finally, the boundaries of the assured quality area are determined. Blade operation capacity analysis method will allow us to reduce the number of environmentally dangerous experiments.
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Wang, Meng-Hui, Shiue-Der Lu, Cheng-Che Hsieh, and Chun-Chun Hung. "Fault Detection of Wind Turbine Blades Using Multi-Channel CNN." Sustainability 14, no. 3 (February 4, 2022): 1781. http://dx.doi.org/10.3390/su14031781.
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This study utilized the multi-channel convolutional neural network (MCNN) and applied it to wind turbine blade and blade angle fault detection. The proposed approach automatically and effectively captures fault characteristics from the imported original vibration signals and identifies their state in multiple convolutional neural network (CNN) models. The result obtained from each model is sent to the output layer, which is a maximum output network (MAXNET), to compute the most accurate state. First, in terms of wind turbine blade state detection, this paper builds blade models based on the normal state and three common fault types, including blade angle anomaly, blade surface damage, and blade breakage. Vibration signals are employed for fault detection. The proposed wind turbine fault diagnosis approach adopts a triaxial vibration transducer and frame grabber to capture vibration signals and then applies the new MCNN algorithm to identify the state. The test results show that the proposed approach could deliver up to 87.8% identification accuracy for four fault types of large wind turbine blades.
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Tin, Trinh Van. "The motion equation of turbine blade by the finite element method." Vietnam Journal of Mechanics 15, no. 4 (December 31, 1997): 42–48. http://dx.doi.org/10.15625/0866-7136/10219.
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In this paper, the finite element method has been applied to deriving the motion equation of turbine blade in coupled bending - bending - torsion vibrations. These equations permit us to develop straightforwardly digital computer programs for studying vibration problems of turbine blades in turbo machinery as well as in other structural dynamic applications.
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Chavan, Umesh, Dhiraj Ghode, Ranveer Ghorpade, Hritika Aacharya, Vaibhav Ubale, Kedar Urunkar, and Nitin Satpute. "Design and analysis of energy efficient wind turbine blades." IOP Conference Series: Materials Science and Engineering 1272, no. 1 (December 1, 2022): 012020. http://dx.doi.org/10.1088/1757-899x/1272/1/012020.
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Inspired by humpback whale flippers, this study presents the effect of leading-edge tubercles on the wind turbine blade. Force models for lift and drag are developed on the blade which have an important role in the wind turbine performance. The study compares the CFD simulation of fluid flow over blade with leading edge tubercles and the conventional blade. Present work also covers strength and random vibration analysis for both the blades. Furthermore, different tubercle blades have been compared for lift and drag coefficients by varying tubercle amplitude. Structural analysis shows tubercled blade is suitable from structural and strength point view. In tubercled blade overall lift to drag-coefficient ratio increased up to 8.5, whereas in conventional this ratio is about 1.7 which is found to be very low. This ratio clearly indicates that in the presence of tubercles on the blade, performance improving even in lower wind speed areas. Overall tubercled blade found to be more suitable for modern wind turbines.
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Shulzhenko, Mykola H., and Anton S. Olkhovskyi. "Vibrational Stresses of Damaged Steam Turbine Blades After Renovation Repair." Journal of Mechanical Engineering 24, no. 1 (March 30, 2021): 42–52. http://dx.doi.org/10.15407/pmach2021.01.042.
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The last-stage blades of K-1000-60/3000 steam turbines operate in a humid steam environment, which causes erosion damage in the blades and reduction in their residual life. The relevance of this work is related to the need to continue the safe operation of such turbine blades. A number of variants of the finite-element models of individual blades and last-stage blades in the disk-blade systems of the above turbines are considered. Results of the numerical study of the influence of blade part removals in erosion damage zones after renovation repair on the vibration characteristics of individual blades and blades in the disk-blade system are presented. An analysis of the stress-strain state under the conditional load from the steam flow during the forced oscillations of individual blades and blades in the disk-blade system is carried out. The loads are given as evenly distributed and linearly variable on blade surfaces. The dependence of the maximum equivalent vibration stresses on excitation frequency is determined. It is assumed that the physical and mechanical properties of the blade material are preserved (as for the original version) after the renovation repair of blades and processing of their surfaces. There is a significantly greater reduction in the vibration stresses of blades in the disk-blade system than in the stresses of individual blades. Graphs of the dependence of the maximum stresses on excitation frequency both for undamaged individual blades and blades in the disk-blade system after their renovation repair are given. Various variants of blade part removals in areas of blade leading and trailing edges are considered. It is shown that with decreasing chords of blades after renovation repair, frequency regions of increased vibration may appear in lower blade parts. In the lower parts of individual blades and blades in the disk-blade system, the maximum stresses increase in comparison with their values in undamaged blades. With the change in the stress-strain state of rotor blades in comparison with the original version of undamaged blades, the possibility of extending their safe lifetime in case of multi-cycle fatigue is assessed. The safe lifetime of the considered blades with a chord of at least 150 mm after their renovation repair can be extended according to their stresses, if the cyclic symmetry of the disk-blade system is not violated, and the physical and mechanical properties of the material are preserved after the processing of damage removal zones on blade trailing edges.
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Kuo, Ying-Che, Chin-Tsung Hsieh, Her-Terng Yau, and Yu-Chung Li. "Study on Unified Chaotic System-Based Wind Turbine Blade Fault Diagnostic System." International Journal of Bifurcation and Chaos 25, no. 03 (March 2015): 1550042. http://dx.doi.org/10.1142/s021812741550042x.
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At present, vibration signals are processed and analyzed mostly in the frequency domain. The spectrum clearly shows the signal structure and the specific characteristic frequency band is analyzed, but the number of calculations required is huge, resulting in delays. Therefore, this study uses the characteristics of a nonlinear system to load the complete vibration signal to the unified chaotic system, applying the dynamic error to analyze the wind turbine vibration signal, and adopting extenics theory for artificial intelligent fault diagnosis of the analysis signal. Hence, a fault diagnostor has been developed for wind turbine rotating blades. This study simulates three wind turbine blade states, namely stress rupture, screw loosening and blade loss, and validates the methods. The experimental results prove that the unified chaotic system used in this paper has a significant effect on vibration signal analysis. Thus, the operating conditions of wind turbines can be quickly known from this fault diagnostic system, and the maintenance schedule can be arranged before the faults worsen, making the management and implementation of wind turbines smoother, so as to reduce many unnecessary costs.
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Li, Yan, He Shen, and Wenfeng Guo. "Simulation and Experimental Study on the Ultrasonic Micro-Vibration De-Icing Method for Wind Turbine Blades." Energies 14, no. 24 (December 8, 2021): 8246. http://dx.doi.org/10.3390/en14248246.
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In cold and humid regions, ice accretion sometimes develops on the blades of wind turbines. Blade icing reduces the power generation of the wind turbine and affects the safe operation of the wind farm. For this paper, ultrasonic micro-vibration was researched as an effective de-icing method to remove ice from the wind turbine blade surface and improve the efficiency of wind turbine power generation. A blade segment with NACA0018 airfoil and the hollow structure at the leading edge was designed. The modal analysis of the blade was simulated by ANSYS, and the de-icing vibration mode was selected. Based on the simulation results, the blade segment sample with PZT patches was machined, and its natural frequencies were measured with an impedance analyzer. A return-flow icing wind tunnel system, and a device used to measure the adhesive strength of ice covering the airfoil blade, were designed and manufactured. The experiments on the adhesive strength of the ice were carried out under the excitation of the ultrasonic vibration. The experimental results show that the adhesive strength of the ice, which was generated under the dynamic flow field condition, was lower than the ice generated by water under the static flow field condition. Under the excitation of the ultrasonic vibration, the adhesive strength of the ice decreased. When the excitation frequency was 21.228 kHz, the adhesive strength was the lowest, which was 0.084 MPa. These research findings lay the theoretical and experimental foundations for researching in-depth the application of the ultrasonic de-icing technology to wind turbines.
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Hussain, Sajjad, Wan Aizon W. Ghopa, S. S. K. Singh, Abdul Hadi Azman, Shahrum Abdullah, Zambri Harun, and Hawa Hishamuddin. "Vibration-Based Fatigue Analysis of Octet-Truss Lattice Infill Blades for Utilization in Turbine Rotors." Materials 15, no. 14 (July 14, 2022): 4888. http://dx.doi.org/10.3390/ma15144888.
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Vibration fatigue characteristics are critical for rotating machinery components such as turbine rotor blades. Lattice structures are gaining popularity in engineering applications due to their unique ability to reduce weight and improve the mechanical properties. This study is an experimental investigation of octet-truss lattice structure utilization in turbine rotor blades for weight reduction and to improve vibration fatigue characteristics. One completely solid and three lattice infilled blades with variable strut thickness were manufactured via additive manufacturing. Both free and forced experimental vibration analyses were performed on the blades to investigate their modal and vibration fatigue characteristics. The blades were subjected to random vibration using a vibration shaker. The response was measured using a triaxial accelerometer in terms of vibration acceleration time histories in the X, Y, and Z directions. Results indicate a weight reduction of up to 24.91% and enhancement in the first natural frequency of up to 5.29% were achieved using lattice infilled blades. The fatigue life of the blades was investigated using three frequency domain approaches, namely, Lalanne, Dirlik and narrow band. The fatigue life results indicate that the 0.25 mm lattice blade exhibits the highest fatigue life, while the solid blade exhibits the lowest fatigue life of all four blades. The fatigue life of the 0.25 mm lattice blade was 1822-, 1802-, and 1819- fold higher compared to that of the solid blade, using the Lalanne, Dirlik, and narrow-band approaches, respectively. These results can serve as the first step towards the utilization of lattice structures in turbine blades, with thermal analysis as the next step. Therefore, apart from being light weight, the octet-truss lattice infilled blades exhibited superior vibration fatigue characteristics to vibration loads, thereby making them a potential replacement for solid blades in turbine rotors.
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Liu, Haoming, Suxiang Yang, Wei Tian, Min Zhao, Xiaoling Yuan, and Bofeng Xu. "Vibration Reduction Strategy for Offshore Wind Turbines." Applied Sciences 10, no. 17 (September 2, 2020): 6091. http://dx.doi.org/10.3390/app10176091.
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The operational environment of offshore wind turbines is much more complex than that of onshore wind turbines. Facing the persistent wind and wave forces, offshore wind turbines are prone to vibration problems, which are not conducive to their long-term operation. Under this background, first, how the wave affects the vibration characteristics of offshore wind turbines is analyzed. Based on the existing wave and wave load models, we analytically show that there exist fluctuating components related to the hydrodynamic frequency in the aerodynamic load and aerodynamic torque of offshore wind turbines. Simulation results based on a GH Bladed platform further validates the analysis. Second, in order to reduce the joint impacts of the wave, wind shear and tower shadow on the wind turbine, a variable pitch control method is proposed. The integrated tower top vibration acceleration signal is superimposed on the collective pitch reference signal, then the triple frequency (3P) fluctuating component of the wind turbine output power and the azimuth angle of each blade are converted into the pitch angle adjustment signal of each blade, which is superimposed on the collective pitch signal for individual pitch control. The simulation results show that the proposed pitch control strategy can effectively smooth the fluctuation of blade root flap-wise load caused by wind and wave, and significantly reduce the fluctuation of aerodynamic torque and output power of offshore wind turbines.
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Katinić, Marko, and Marko Ljubičić. "Numerical and Experimental Vibration Analysis of a Steam Turbine Rotor Blade." Tehnički glasnik 15, no. 4 (November 1, 2021): 462–66. http://dx.doi.org/10.31803/tg-20210302210045.
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Damage to the rotor blade of a steam turbine is a relatively common problem and is one of the leading causes of sudden and unplanned shutdowns of a steam turbine. Therefore, the high reliability of the rotor blades is very important for the safe and economical operation of the steam turbine. To ensure high reliability, it is necessary to perform a vibration analysis of the rotor blades experimentally and in a computer environment. In this paper, a modal analysis was performed on the twisted blade of the last stage of the turbine in the Ansys software. The results of the modal analysis of the stationary rotor blade were compared with the results obtained by the bump test, which confirmed the numerical model of the blade. A modal analysis of a rotating rotor blade was performed on the same numerical model, and Campbell diagrams were plotted to determine the critical speed
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Kadambi, J. R., R. D. Quinn, and M. L. Adams. "Turbomachinery Blade Vibration and Dynamic Stress Measurements Utilizing Nonintrusive Techniques." Journal of Turbomachinery 111, no. 4 (October 1, 1989): 468–74. http://dx.doi.org/10.1115/1.3262295.
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The vibration of large turbomachinery blading is well known to be one of the most important design factors in modern turbomachinery. Typically, blade vibration is dominated by the unsteady flow phenomena and the interaction effects set up by vibration of blades within a high-velocity compressible fluid medium. This paper addresses the feasibility of developing an in-service noninterference measuring/monitoring system for steam turbine and gas turbine jet engine blade vibrations and stresses. The major purpose of such a measurement system is to provide a technically feasible, cost-effective means to isolate potential turbine and fan blade failures before they occur; thus minimizing costly machinery failure and risk of injury. The techniques that are examined include magnetic, inductive, optical, and laser and acoustic Doppler measurement methods. It appears likely that the most feasible and promising approach would include use of a few properly chosen measurement points on the blading in combination with use of advanced finite-element computational techniques and vibration modal methods. The modal analysis, performed experimentally and/or computationally, is especially useful in converting vibration measurements to the desired dynamic stresses.
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Joshuva, A., and V. Sugumaran. "A Comparative Study for Condition Monitoring on Wind Turbine Blade using Vibration Signals through Statistical Features: a Lazy Learning Approach." International Journal of Engineering & Technology 7, no. 4.10 (October 2, 2018): 190. http://dx.doi.org/10.14419/ijet.v7i4.10.20833.
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This study is to identify whether the wind turbine blades are in good or faulty conditions. If faulty, then the objective to find which fault condition are the blades subjected to. The problem identification is carried out by machine learning approach using vibration signals through statistical features. In this study, a three bladed wind turbine was chosen and faults like blade cracks, hub-blade loose connection, blade bend, pitch angle twist and blade erosion were considered. Here, the study is carried out in three phases namely, feature extraction, feature selection and feature classification. In phase 1, the required statistical features are extracted from the vibration signals which obtained from the wind turbine through accelerometer. In phase 2, the most dominating or the relevant feature is selected from the extracted features using J48 decision tree algorithm. In phase 3, the selected features are classified using machine learning classifiers namely, K-star (KS), locally weighted learning (LWL), nearest neighbour (NN), k-nearest neighbours (kNN), instance based K-nearest using log and Gaussian weight kernels (IBKLG) and lazy Bayesian rules classifier (LBRC). The results were compared with respect to the classification accuracy and the computational time of the classifier.
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Xu, Lianchen, Xiaohui Jin, Zhen Li, Wanquan Deng, Demin Liu, and Xiaobing Liu. "Particle Image Velocimetry Test for the Inter-Blade Vortex in a Francis Turbine." Processes 9, no. 11 (November 4, 2021): 1968. http://dx.doi.org/10.3390/pr9111968.
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Hydropower units are usually operated in non-design conditions because of power grid requirements. In a partial-load condition, an inter-blade vortex phenomenon occurs between the runner blades of a Francis turbine, causing pressure pulsation and unit vibration, which hinder the safe and stable operation of power stations. However, the mechanism through which the inter-blade vortex generation occurs is not entirely clear. In this study, a specific model of the Francis turbine was used to investigate and visually observe the generation of the blade vortex in Francis turbines in both the initial inter-blade and vortex development zones. Particle image velocimetry was used for this purpose. In addition, we determined the variation law of the inter-blade vortex in the Francis turbine. We found that the size and strength of the inter-blade vortex depend on the unit speed of the turbine. The higher the unit speed is, the stronger the inter-blade vortex becomes. We concluded that the inter-blade vortex of such turbines originates from the pressure surface or secondary flow and stall of the blade at the inlet side of the runner at high unit speeds, and also from the backflow zone of the suction surface of the blade at low unit speeds.
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Lee, Sang-Lae. "Active vibration suppression of wind turbine blades integrated with piezoelectric sensors." Science and Engineering of Composite Materials 28, no. 1 (January 1, 2021): 402–14. http://dx.doi.org/10.1515/secm-2021-0039.
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Abstract As the wind turbine size gets larger, the optimal design of blades, which is a major source of energy for the wind turbines and also the cause of loads, is becoming more important than anything else. Therefore, reducing the load on the blade should be the top priority in designing a blade. In this article, we studied the vibration control of the stiffened wind blades subjected to a wind load with piezoelectric sensors and actuators to mitigate fluctuations in loading and adding damping to the blade. The model is a laminated composite blade with a shear web and the PZT piezomaterial layers embedded on the top and bottom surfaces act as a sensor and actuator, respectively. A uniformly distributed external wind load is assumed over the entire plate surface for simplicity. The first-order shear deformation (FSDT) theory is adopted, and Hamilton’s principle is used to derive the finite element equation of motion. The modal superposition technique and the Newmark- β \beta method are used in numerical analysis to calculate the dynamic response. Using the constant gain negative velocity feedback control algorithm, vibration characteristics and transient responses are compared. Furthermore, vibration control at various locations of the shear webs subjected to an external load is discussed in detail. Through various calculation results performed in this study, this article proposes a method of designing a blade that can reduce the load by actively responding to the external load acting on the wind turbine blade.
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Wang, Xu Dong, Li Cun Wang, Xian Ming Zhang, and Jun Feng. "Flexible and Vibration Characteristics Simulation for the Large Megawatt Size Wind Turbine Blades." Advanced Materials Research 217-218 (March 2011): 363–67. http://dx.doi.org/10.4028/www.scientific.net/amr.217-218.363.
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In the development of new large megawatt size wind turbines, aerodynamic and structural reserch is interesting and important for study wind turbine performace and boost the development of wind power. In this paper, the aerodynamic and aeroelastic characteristic of blades is investigated and presented based on Blade Element Momentum and Hamilton theory. Then the flexible characteristics of balde is researched with the aerodynamic and aeroelastic model of the rotor. The flapwise and edgewise displacements, velocities and accelerations of blade tip are simulated and plotted to validate the model which is presented in this paper. The results have very important significance to investigate the vibration and fatigue lifetime of the wind turbine blades.
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Souri, Mohammad, Farshad Moradi Kashkooli, Madjid Soltani, and Kaamran Raahemifar. "Effect of Upstream Side Flow of Wind Turbine on Aerodynamic Noise: Simulation Using Open-Loop Vibration in the Rod in Rod-Airfoil Configuration." Energies 14, no. 4 (February 22, 2021): 1170. http://dx.doi.org/10.3390/en14041170.
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Adaptive and flexible control techniques have recently been examined as methods of controlling flow and reducing the potential noise in vertical axis wind turbines. Two-Dimensional (2D) fluid flow simulation around rod-airfoil is addressed in this study as a simple component of the wind turbine by using Unsteady Reynolds Averaged Navier–Stokes (URANS) equations for prediction of noise using Ffowcs Williams-Hawkings (FW-H) analogy. To control the flow and reduce noise, the active controlling vibration rod method is utilized with a maximum displacement ranging from 0.01 C to 1 C (C: airfoil chord). Acoustic assessment indicates that the leading edge of the blade produces noise, that by applying vibration in cylinder, blade noise in 0.1 C and 1 C decreases by 22 dB and 35 dB, respectively. Applying vibration is aerodynamically helpful since it reduces the fluctuations in the airfoil lift force by approximately 48% and those in the rod by about 46%. Strouhal assessment (frequency) shows that application of control is accompanied by 20% increase. Applying vibration in the rod reduces the flow fluctuations around the blade, thus reduces the wind turbine blade noise. This idea, as a simple example, can be used to study the incoming flow to turbines and their blades that are affected by the upstream flow.
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Aswin, Fajar, and Zaldy Sirwansyah Suzen. "IMPLEMENTASI SENSOR MEMS AKSELEROMETER SEBAGAI ALAT PENGUKUR GETARAN PADA TURBIN ANGIN." Jurnal Poli-Teknologi 18, no. 3 (November 7, 2019): 225–32. http://dx.doi.org/10.32722/pt.v18i3.2340.
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Many techniques are available in the market to measure and analyze vibrations caused by rotating machines and the structure of the machine itself, but require expensive resources to identify the problem of damage. Generally these expensive equipment use conventional sensors such as eddy-current sensors, swing coil velocity sensors and piezoelectric transducer sensors to measure vibration. The implementation of a vibration measuring device in the form of an accelerometer sensor with a type of Micro Electro Mechanical System (MEMS) and a signal processing unit (Arduino Mega microcontroller) is used to measure vibrations that occur in small-scale horizontal type wind turbine blades. Experiments were carried out to check the accelerometer's ability to detect vibration response on wind turbine blades with the free vibration position. Then the signal in the form of the time domain will be converted into the frequency domain to get the dominant frequency value of the turbine blade, which is then analyzed to be compared with the B & K VibroPort 80 vibration meter. The experimental results show that the MEMS type accelerometer sensor can be applied to measure the free vibration conditions on wind turbine blades with an error percentage below 6%.
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Guo, Shijie. "Investigations on the Blade Vibration of a Radial Inflow Micro Gas Turbine Wheel." International Journal of Rotating Machinery 2007 (2007): 1–10. http://dx.doi.org/10.1155/2007/29270.
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This paper demonstrates the investigations on the blade vibration of a radial inflow micro gas turbine wheel. Firstly, the dependence of Young's modulus on temperature was measured since it is a major concern in structure analysis. It is demonstrated that Young's modulus depends on temperature greatly and the dependence should be considered in vibration analysis, but the temperature gradient from the leading edge to the trailing edge of a blade can be ignored by applying the mean temperature. Secondly, turbine blades suffer many excitations during operation, such as pressure fluctuations (unsteady aerodynamic forces), torque fluctuations, and so forth. Meanwhile, they have many kinds of vibration modes, typical ones being blade-hub (disk) coupled modes and blade-shaft (torsional, longitudinal) coupled modes. Model experiments and FEM analysis were conducted to study the coupled vibrations and to identify the modes which are more likely to be excited. The results show that torque fluctuations and uniform pressure fluctuations are more likely to excite resonance of blade-shaft (torsional, longitudinal) coupled modes. Impact excitations and propagating pressure fluctuations are more likely to excite blade-hub (disk) coupled modes.
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Song, Jian, Junying Chen, Yufei Wu, and Lixiao Li. "Topology Optimization-Driven Design for Offshore Composite Wind Turbine Blades." Journal of Marine Science and Engineering 10, no. 10 (October 13, 2022): 1487. http://dx.doi.org/10.3390/jmse10101487.
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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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Nikhamkin, M., and B. Bolotov. "Experimental and Finite Element Analysis of Natural Modes and Frequencies of Hollow Fan Blades." Applied Mechanics and Materials 467 (December 2013): 306–11. http://dx.doi.org/10.4028/www.scientific.net/amm.467.306.
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Natural modes and frequencies of gas turbine engine hollow fan blades were experimentally investigated. The blades were produced with the method of super-plastic molding and pressure welding combination. Two independent experimental methods were used: three-component scanning laser vibrometry and impact modal analysis. Natural frequencies and vibration modes of a hollow fan blade and stress fields corresponding to the natural modes were got. The finite element modal analysis was carried out. The hollow fan blade was stated to have particular natural vibration modes. The investigation results can be used to detune the resonance vibrations and to verify calculation models.
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Wang, Lu, Shun Qiang Ye, and Rui Meng. "Finite Element Modal Analysis for Steam Turbine Blade Based on ANSYS." Applied Mechanics and Materials 260-261 (December 2012): 368–71. http://dx.doi.org/10.4028/www.scientific.net/amm.260-261.368.
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In response to the vibration fatigue fracture of the steam turbine blade,we construct the 3D model of cracked blade based on the actual crack location,then modal analysis is conducted to the blade with crack and one without crack using the finite element software ANSYS.Thus,we can get the respective natural frequencies and the figure of main vibration modes.The comprasion results show that the existence of the crack can make the natural frequencies of blades drop and the blades have the greatest sway and twisting deformation along the Y axis.These characteristics above can effectively identify the presence of blade cracked. It has crucial meaning for achieving cracked blade online monitoring.
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Kotambkar, Mangesh S. "Modal Analysis of Mistuned Turbine Blade Packet Due to Combined Blade and Lacing Wire Damage." Volume 24, No 3, September 2019 24, no. 3 (September 2019): 546–57. http://dx.doi.org/10.20855/ijav.2019.24.31391.
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The turbine disk blade system is a cyclic symmetric structure, initially tuned with all its blades perfectly identical in geometry and material properties; similarly interconnecting lacing wires are of equal stiffness. The cyclic symmetry of the bladed disks gets destroyed due to small differences in material properties or geometric variation between individual blades or lacing wires causing mistuning. Although mistuning is typically small, it can have a drastic effect on the dynamic response of the system. In particular, mistuning can also cause vibration localization for a few blades and the associated concentration of vibration energy can lead to an increase in blade amplitude and stress levels. Numerical simulations are performed with the characteristic equations of the simplified continuum model. Two different damage severity indices are included in the model to study the combined effect of cracked blades and damaged lacing wires on the natural frequencies of grouped blades. This study highlights the characteristic changes in the sub modal frequencies under combined damage in a stand still position. Although the major cause of mistuning is blade damage, lacing wire damage is more frequent and often acts as a precursor to blade damage and thus the present study focuses on mistuning due to combined damage.
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Rahmani, Arash, Ahmad Ghanbari, and Ali Mohammadi. "Experimental Modal Analysis of a First Stage Blade in ALSTOM Gas Turbine." Applied Mechanics and Materials 624 (August 2014): 303–7. http://dx.doi.org/10.4028/www.scientific.net/amm.624.303.
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Failures of turbine blades are one of the most critical problems in power generating industry. Among the different failure mechanisms, resonant vibration of blades has a major role and therefore is the subject of many recent research works. Therefore, in this paper, modal analysis of a first stage blade in ALSTOM gas turbine is investigated and natural frequencies and vibration modes of blade are found in various conditions. For this purpose, a cloud-point model of a gas turbine blade has been created using 3D Laser Digitizer. Then the numerical calculation by finite element method using ANSYS software based on experimental test conditions is utilized and Experimental natural frequencies have been obtained. The results show acceptable agreement between the experimental and FEM results.
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Escaler, Xavier, and Toufik Mebarki. "Full-Scale Wind Turbine Vibration Signature Analysis." Machines 6, no. 4 (December 7, 2018): 63. http://dx.doi.org/10.3390/machines6040063.
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A sample of healthy wind turbines from the same wind farm with identical sizes and designs was investigated to determine the average vibrational signatures of the drive train components during normal operation. The units were variable-speed machines with three blades. The rotor was supported by two bearings, and the drive train connected to an intermediate three-stage planetary/helical gearbox. The nominal 2 MW output power was regulated using blade pitch adjustment. Vibrations were measured in exactly the same positions using the same type of sensors over a six-month period covering the entire range of operating conditions. The data set was preliminary validated to remove outliers based on the theoretical power curves. The most relevant frequency peaks in the rotor, gearbox, and generator vibrations were detected and identified based on averaged power spectra. The amplitudes of the peaks induced by a common source of excitation were compared in different measurement positions. A wind speed dependency of broadband vibration amplitudes was also observed. Finally, a fault detection case is presented showing the change of vibration signature induced by a damage in the gearbox.
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Jenkins, Maurice A. "Turbine blade vibration detection system." Journal of the Acoustical Society of America 89, no. 6 (June 1991): 3024. http://dx.doi.org/10.1121/1.400764.
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Luongo, Michael C. "Turbine blade vibration detection apparatus." Journal of the Acoustical Society of America 80, no. 6 (December 1986): 1865. http://dx.doi.org/10.1121/1.394236.
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Yi, Lee Zhou, and Choe-Yung Teoh. "Modal Analysis of Vertical Wind Turbine Blade." MATEC Web of Conferences 217 (2018): 01003. http://dx.doi.org/10.1051/matecconf/201821701003.
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Wind turbines cannot simply be installed in Malaysia due to low wind speed condition. the project has analyzed the existing wind turbine blade (Aeolos-V 1k) design based on modal properties using computational approach (ANSYS Workbench) and redesign it. the modal analysis is simulated to observe natural frequency and corresponding mode shaped of the system under free vibration. the flow induced vibration can cause blade failure due to resonance or fatigue. Fluid Structural Interaction (FSI) ANSYS is used to the determined the interaction between the wind flow and the blade. Harmonic Response ANSYS is used to analyze the frequency response of the blade under wind induced vibration. After modification, the first mode has increased from 91.42 Hz to 102.12, since it is more than 50.92 Hz (Turbine maximum operating frequency), resonance would not occur during operating condition. the Aeolos-V’s blade has been modified by using. teak wood material and. redesign the blade for weight. reduction and aim for lower blade cost. the weight of modified blade has reduced 72.8 % after using teak wood and the efficiency of the wind turbine also increased. Modified design has been tested under Malaysia maximum wind speed of 9.44 m/s, the yield stress of teak wood (10.3 MPa) is higher than the maximum stress (4.2 MPa) obtained under force vibration which gives safety factor of 2.4. Hence, modified blade is reliable, efficient and more economic for Malaysia.
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Hussain, Sajjad, Wan Aizon W. Ghopa, S. S. K. Singh, Abdul Hadi Azman, and Shahrum Abdullah. "Experimental and Numerical Vibration Analysis of Octet-Truss-Lattice-Based Gas Turbine Blades." Metals 12, no. 2 (February 15, 2022): 340. http://dx.doi.org/10.3390/met12020340.
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This paper aims to investigate the utilization of octet truss lattice structures in gas turbine blades to achieve weight reduction and improvement in vibration characteristics, which are desired for turbine blades to improve the efficiency and load capacity of turbines. A solid blade model using NACA 23012 airfoil was designed as reference. Three lattice-based blades were designed and manufactured via additive manufacturing by replacing the internal volume of solid blades with octet truss unit cells of variable strut thickness. Experimental and numerical vibration analyses were performed on the blades to establish their suitability for potential use in turbine blades. A maximum weight reduction of 24.91% was achieved. The natural frequencies of lattice blades were higher than those of solid blades. A stress reduction up to 38.6% and deformation reduction of up to 21.5% compared with solid blades were also observed. Both experimental and numerical results showed good agreement with a maximum difference of 3.94% in natural frequencies. Therefore, apart from being lightweight, octet-truss-lattice-based blades have excellent vibration characteristics and low stress levels, thereby making these blades ideal for enhancing the efficiency and durability of gas turbines.
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He, Ying, Lei Liu, Hao Zhou, and Xinshua Chu. "Biaxial Fatigue Loading System for Electromagnetic Excitation of Wind Turbine Blades." Scientific Journal of Technology 4, no. 7 (July 20, 2022): 60–64. http://dx.doi.org/10.54691/sjt.v4i7.1276.
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Based on the shortcomings of the current detection methods for wind power blades, an electromagnetic excitation biaxial fatigue loading system is designed. The loading method mainly adopts the principle of electromagnetic actuators. The loading part is mainly composed of electromagnet cores and coils. The blades exert electromagnetic force to achieve blade vibration. The dual-axis loading can be more in line with the actual working conditions of the blade. Electromagnetic loading mechanisms are installed in the two directions of the blade's waving and swaying respectively, and the electromagnetic force is applied in the two directions of the blade's waving and swaying at the same time. Vibration frequency, so that the vibration reaches the natural frequency of the blade. In addition, the clamping mechanism of the blade is improved, and a mechanical clamping mechanism is designed, which comprehensively uses the ball screw, timing belt, ratchet and came to realize the positioning and clamping of the blade.
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Zhao, Wei Qiang, Yong Xian Liu, Mo Wu Lu, and Qing Jun Guo. "Vibration Characteristics Analysis of an Aero-Engine Turbine Blade." Advanced Materials Research 487 (March 2012): 894–97. http://dx.doi.org/10.4028/www.scientific.net/amr.487.894.
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This paper introduces the FEA method for a certain type of aero-engine turbine blade and makes a vibration characteristics analysis to this aero-engine turbine blade based on this method. The vibration characteristic of this aero-engine turbine blade is studied and the natural modal of the turbine blade is calculated based on UG software. The first six natural frequencies and mode shapes are given. According to the analysis results the dynamic characteristics of the blade are discussed. The analysis method and results in this paper can be used for further study on optimal design and vibration safety verification for the blade.
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Gao, Jie, Fusheng Meng, Xiaoquan Jia, Weiliang Fu, and Guoqiang Yue. "Reduction of aerodynamic forces on turbine blading by asymmetric layout of struts based on flow interaction between rotor-strut-volute." Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 233, no. 8 (April 16, 2019): 974–87. http://dx.doi.org/10.1177/0957650919839583.
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The flows in the power turbine and nonaxisymmetric exhaust volute with struts are closely coupled and inherently unsteady for marine gas turbines, and the flow interactions between them have a significant influence on the rotor and strut blade aerodynamic force characteristics; however, the asymmetric flow interactions have not been taken into account properly in current turbine design approaches. This paper is a continuation of the previous work and aims to clarify effects of different symmetrical and asymmetric layouts of struts on the flow interactions between power turbine and exhaust volute, in an attempt to seek an optimal layout of struts with the objective of making use of the mentioned asymmetric flow interactions to reduce the rotor and strut blade aerodynamic forces. This work was carried out using coupled unsteady simulations with the full annulus computational domain including 76 rotor blades, 9 strut blades, and an exhaust volute. Results show that the level of aerodynamic force at specific frequencies on the power turbine blade surface can be reduced by applying a proper distribution of asymmetric layout of struts; using the asymmetric strut design, although the reduction of the rotor blade aerodynamic force is weak, the strut blade aerodynamic force has been reduced significantly; the asymmetric layout of struts does not improve the overall flow characteristics of turbines very much. The present results indicate that it is possible to reduce vibration and increase blade fatigue life by asymmetric strut designs.
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Alshroof, Osama N., Gareth L. Forbes, Nader Sawalhi, Robert B. Randall, and Guan H. Yeoh. "Computational Fluid Dynamic Analysis of a Vibrating Turbine Blade." International Journal of Rotating Machinery 2012 (2012): 1–15. http://dx.doi.org/10.1155/2012/246031.
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This study presents the numerical fluid-structure interaction (FSI) modelling of a vibrating turbine blade using the commercial software ANSYS-12.1. The study has two major aims: (i) discussion of the current state of the art of modelling FSI in gas turbine engines and (ii) development of a “tuned” one-way FSI model of a vibrating turbine blade to investigate the correlation between the pressure at the turbine casing surface and the vibrating blade motion. Firstly, the feasibility of the complete FSI coupled two-way, three-dimensional modelling of a turbine blade undergoing vibration using current commercial software is discussed. Various modelling simplifications, which reduce the full coupling between the fluid and structural domains, are then presented. The one-way FSI model of the vibrating turbine blade is introduced, which has the computational efficiency of a moving boundary CFD model. This one-way FSI model includes the corrected motion of the vibrating turbine blade under given engine flow conditions. This one-way FSI model is used to interrogate the pressure around a vibrating gas turbine blade. The results obtained show that the pressure distribution at the casing surface does not differ significantly, in its general form, from the pressure at the vibrating rotor blade tip.
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Song, Xiaowen, Zhitai Xing, Yan Jia, Xiaojuan Song, Chang Cai, Yinan Zhang, Zekun Wang, Jicai Guo, and Qingan Li. "Review on the Damage and Fault Diagnosis of Wind Turbine Blades in the Germination Stage." Energies 15, no. 20 (October 12, 2022): 7492. http://dx.doi.org/10.3390/en15207492.
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In recent years, wind turbines have shown a maximization trend. However, most of the wind turbine blades operate in areas with a relatively poor natural environment. The stability, safety, and reliability of blade operation are facing many challenges. Therefore, it is of great significance to monitor the structural health of wind turbine blades to avoid the failure of wind turbine outages and reduce maintenance costs. This paper reviews the commonly observed types of damage and damage detection methods of wind turbine blades. First of all, a comprehensive summary of the common embryonic damage, leading edge erosion, micro-cracking, fiber defects, and coating defects damage. Secondly, three fault diagnosis methods of wind turbine blades, including nondestructive testing (NDT), supervisory control and data acquisition (SCADA), and vibration signal-based fault diagnosis, are introduced. The working principles, advantages, disadvantages, and development status of nondestructive testing methods are analyzed and summarized. Finally, the future development trend of wind turbine blade detection and diagnosis technology is discussed. This paper can guide the use of technical means in the actual detection of wind turbine blades. In addition, the research prospect of fault diagnosis technology can be understood.
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Abdelrhman, Ahmed M., M. Salman Leong, Somia Alfatih M. Saeed, and Salah M. Ali Al-Obiadi Al Obiadi. "A Review of Vibration Monitoring as a Diagnostic Tool for Turbine Blade Faults." Applied Mechanics and Materials 229-231 (November 2012): 1459–63. http://dx.doi.org/10.4028/www.scientific.net/amm.229-231.1459.
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Vibration monitoring is widely recognized as an effective tool for the detection and diagnosis of incipient failures of gas turbines. This paper presents a review of vibration based methods for turbine blade faults. Methods typically involved analysis of blade passing frequencies, and extraction of dynamic signals from the measured vibration response. This includes frequency analysis, wavelet analysis, neural networks and fuzzy logic and model based analysis. The literature reviewed showed that vibration could detect most types of blade faults on the basis that dynamic signals are correctly extracted using the most appropriate signal processing method.