Статті в журналах з теми "Bladed Disks Dynamic"
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1
Zhao, Zhi Bin, Er Ming He, and Hong Jian Wang. "Experimental Investigation on Natural Characteristics and Forced Response of Bladed Disks." Applied Mechanics and Materials 105-107 (September 2011): 34–37. http://dx.doi.org/10.4028/www.scientific.net/amm.105-107.34.
Повний текст джерелаАнотація:
The results of an experimental investigations on the natural characteristics of tuned bladed disk and forced dynamic responses of mistuned bladed disks are reported. Three experimental bladed disks are discussed: a tuned specimen of periodic symmetry with 12-blades which are nominally identical, and two mistuned specimens, which feature small blade-to-blade variations by adding slight blocks to blade tips. All the specimens are subject to travelling wave excitation produced by piezo-electric actuators sticking on the root of blades. The primary objective of this experiment is to observe the natural characteristics of tuned bladed disk, and to research the impact of mistuning on the forced response blade amplitude magnification. Analytical predictions about the blade amplitude magnification factor are verified by the experimental results.
2
Judge, J., C. Pierre, and O. Mehmed. "Experimental Investigation of Mode Localization and Forced Response Amplitude Magnification for a Mistuned Bladed Disk." Journal of Engineering for Gas Turbines and Power 123, no. 4 (October 1, 2000): 940–50. http://dx.doi.org/10.1115/1.1377872.
Повний текст джерелаАнотація:
The results of an experimental investigation on the effects of random blade mistuning on the forced dynamic response of bladed disks are reported. The primary aim of the experiment is to gain understanding of the phenomena of mode localization and forced response blade amplitude magnification in bladed disks. A stationary, nominally periodic, 12-bladed disk with simple geometry is subjected to a traveling-wave out-of-plane “engine order” excitation delivered via phase-shifted control signals sent to piezoelectric actuators mounted on the blades. The bladed disk is then mistuned by the addition of small, unequal weights to the blade tips, and it is again subjected to a traveling wave excitation. The experimental data is used to verify analytical predictions about the occurrence of localized mode shapes, increases in forced response amplitude, and changes in resonant frequency due to the presence of mistuning. Very good agreement between experimental measurements and finite element analysis is obtained. The out-of-plane response is compared and contrasted with the previously reported in-plane mode localization behavior of the same test specimen. This work also represents an important extension of previous experimental study by investigating a frequency regime in which modal density is lower but disk-blade interaction is significantly greater.
3
Bladh, R., M. P. Castanier, and C. Pierre. "Component-Mode-Based Reduced Order Modeling Techniques for Mistuned Bladed Disks—Part I: Theoretical Models." Journal of Engineering for Gas Turbines and Power 123, no. 1 (April 2, 2000): 89–99. http://dx.doi.org/10.1115/1.1338947.
Повний текст джерелаАнотація:
Component mode synthesis (CMS) techniques are widely used for dynamic analyses of complex structures. Significant computational savings can be achieved by using CMS, since a modal analysis is performed on each component structure (substructure). Mistuned bladed disks are a class of structures for which CMS is well suited. In the context of blade mistuning, it is convenient to view the blades as individual components, while the entire disk may be treated as a single component. Individual blade mistuning may then be incorporated into the CMS model in a straightforward manner. In this paper, the Craig–Bampton (CB) method of CMS is formulated specifically for mistuned bladed disks, using a cyclic disk description. Then a novel secondary modal analysis reduction technique (SMART) is presented: a secondary modal analysis is performed on a CB model, yielding significant further reduction in model size. In addition, a straightforward non-CMS method is developed in which the blade mistuning is projected onto the tuned system modes. Though similar approaches have been reported previously, here it is generalized to a form that is more useful in practical applications. The theoretical models are discussed and compared from both computational and practical perspectives. It is concluded that using SMART, based on a CB model, has tremendous potential for highly efficient, accurate modeling of the vibration of mistuned bladed disks.
4
Carassale, Luigi, and Elena Rizzetto. "Experimental Investigation on a Bladed Disk with Traveling Wave Excitation." Sensors 21, no. 12 (June 8, 2021): 3966. http://dx.doi.org/10.3390/s21123966.
Повний текст джерелаАнотація:
Bladed disks are key components of turbomachines and their dynamic behavior is strongly conditioned by their small accidental lack of symmetry referred to as blade mistuning. The experimental identification of mistuned disks is complicated due to several reasons related both to measurement and data processing issues. This paper describes the realization of a test rig designed to investigate the behavior of mistuned disks and develop or validate data processing techniques for system identification. To simplify experiments, using the opposite than in the real situation, the disk is fixed, while the excitation is rotating. The response measured during an experiment carried out in the resonance-crossing condition is used to compare three alternative techniques to estimate the frequency-response function of the disk.
5
Gao, Shimin, Yanrong Wang, Zhiwei Sun, and Siyuan Chen. "A Prediction Method with Altering Equivalent Stiffness for Damping Evaluation of Shrouded Bladed Disk Dynamic Systems." Symmetry 13, no. 3 (March 4, 2021): 413. http://dx.doi.org/10.3390/sym13030413.
Повний текст джерелаАнотація:
In turbomachinery bladed disks are typical cyclic symmetric structures where high-cycle fatigue of the blades can easily occur. Increasing the shroud structure is an effective blade vibration reduction method using the dry friction of the shroud contact surface to dissipate vibration energy. During one vibration cycle of the blade, the contact surface of the shroud may have one or several states of stick, slip, and separation due to the different amplitude of blade, which affects not only the damping, but also the stiffness of the system. This paper proposes a method to analyze the damping characteristics of blades with shroud considering the change of equivalent contact stiffness of the shroud by using the finite element method. With a 2D contact model, this method calculates the equivalent damping and obtains the damping characteristic curve to evaluate the damping of shroud. During the design phase, the objective is that when resonance occurs, the shroud can provide the optimal damping ratio under the allowable vibration stress of the blade. The parameter sensitivity of the damping characteristic for one bladed disk with parallel shroud is investigated. It is shown that vibration phase angle, contact stiffness, contact force, friction coefficient significantly influence the damping characteristics.
6
Mignolet, M. P., A. J. Rivas-Guerra, and J. P. Delor. "Identification of Mistuning Characteristics of Bladed Disks From Free Response Data—Part I." Journal of Engineering for Gas Turbines and Power 123, no. 2 (June 9, 1999): 395–403. http://dx.doi.org/10.1115/1.1338949.
Повний текст джерелаАнотація:
The focus of the present two-part investigation is on the estimation of the dynamic properties, i.e., masses, stiffnesses, natural frequencies, mode shapes and their statistical distributions, of turbomachine blades to be used in the accurate prediction of the forced response of mistuned bladed disks. As input to this process, it is assumed that the lowest natural frequencies of the blades alone have been experimentally measured, for example, in a broach block test. Since the number of measurements is always less than the number of unknowns, this problem is indeterminate in nature. In this first part of the investigation, two distinct approaches will be investigated to resolve the shortfall of data. The first one relies on the imposition of as many constraints as needed to ensure a unique solution to this identification problem. Specifically, the mode shapes and modal masses of the blades are set to their design/tuned counterparts while the modal stiffnesses are varied from blade to blade to match the measured natural frequencies. The second approach, based on the maximum likelihood principle, yields estimates of all the structural parameters of the blades through the minimization of a specified “cost function.” The accuracy of these two techniques in predicting the forced response of mistuned bladed disks will be assessed on simple dynamic models of the blades.
7
Sommariva, Alessandro, and Stefano Zucca. "A Comparison between Two Reduction Strategies for Shrouded Bladed Disks." Applied Sciences 8, no. 10 (September 26, 2018): 1736. http://dx.doi.org/10.3390/app8101736.
Повний текст джерелаАнотація:
Shrouded bladed disks exhibit a nonlinear dynamic behavior due to the contact interfaces at shrouds between neighboring blades. As a result, reduced order models (ROMs) are mandatory to compute the response levels during the design phase for high cycle fatigue (HCF) life assessment. In this paper, two reduction strategies for shrouded bladed disk reduction are presented. Both approaches rely on: (i) the cyclic symmetry of the linear bladed disk with open shrouds to perform only single sector calculations, (ii) the Craig–Bampton (CB) method to reduce the number of physical degrees of freedom (dofs). The two approaches are applied to a set of test cases in order to evaluate and compare their accuracy and the associated computational effort. Although both approaches allow for generating accurate ROMs, it is found that the numerical efficiency of the two methods depends on the ratio of the number of nodes at the inter-sector interfaces over the number of inner nodes of the elementary sector model.
8
Moraga, Greco, Mònica Egusquiza, David Valentín, Carme Valero, and Alexandre Presas. "Analysis of the Mode Shapes of Kaplan Runners." Applied Sciences 12, no. 13 (July 2, 2022): 6708. http://dx.doi.org/10.3390/app12136708.
Повний текст джерелаАнотація:
To prevent lifetime shortening and premature failure in turbine runners, it is of paramount importance to analyse and understand its dynamic response and determine the factors that affect it. In this paper, the dynamic response of a Kaplan runner is analysed in air by numerical and experimental methods. First, to start the analysis of Kaplan runner mode shapes, its geometry is simplified and modelled as a bladed disk. Bladed disks with different blade numbers are investigated, by numerical simulation, in order to understand the influence of this parameter on its modal characteristics. Then, mode shapes extracted are characterized and a classification is proposed. Second, an existing Kaplan runner is simulated by Finite Elements Method (FEM) and its mode shapes are extracted. The obtained results are contrasted with the bladed disks mode shapes, in order to validate the classification proposed. The simulated Kaplan runner is also experimentally studied. A numerical modal analysis is carried out in the real runner. Different, global and local, mode shapes are identified. The global mode shapes extracted by numerical and experimental modal analysis are compared and discussed. Finally, the local mode shapes identified are commented and explained by means of numerical simulation.
9
Flowers, G. T., and Fang Sheng Wu. "A Study of the Influence of Bearing Clearance on Lateral Coupled Shaft/Disk Rotordynamics." Journal of Engineering for Gas Turbines and Power 115, no. 2 (April 1, 1993): 279–86. http://dx.doi.org/10.1115/1.2906706.
Повний текст джерелаАнотація:
This study examines the influence of bearing clearance on the dynamic behavior of a rotating, flexible disk/shaft system. Most previous work in nonlinear rotordynamics has tended to concentrate separately on shaft vibration or on bladed disk vibration, neglecting the coupling dynamics between them. The current work examines the important rotordynamic behavior of coupled disk/shaft dynamics. A simplified nonlinear model is developed for lateral vibration of a rotor system with a bearing clearance nonlinearity. The steady-state dynamic behavior of this system is explored using numerical simulation and limit cycle analysis. It is demonstrated that bearing clearance effects can produce superharmonic vibration that may serve to excite high-amplitude disk vibration. Such vibration could lead to significantly increased bearing loads and catastrophic failure of blades and disks. In addition, multivalued responses and aperiodic behavior were observed.
10
Petrov, E. P., and D. J. Ewins. "Advanced Modeling of Underplatform Friction Dampers for Analysis of Bladed Disk Vibration." Journal of Turbomachinery 129, no. 1 (February 1, 2006): 143–50. http://dx.doi.org/10.1115/1.2372775.
Повний текст джерелаАнотація:
Advanced structural dynamic models for both wedge and split underplatform dampers have been developed. The new damper models take into account inertia forces and the effects of normal load variation on stick-slip transitions at the contact interfaces. The damper models are formulated for the general case of multiharmonic forced response analysis. An approach for using the new damper models in the dynamic analysis of large-scale finite element models of bladed disks is proposed and realized. Numerical investigations of bladed disks are performed to demonstrate the capabilities of the new models and an analysis of the influence of the damper parameters on the forced response of bladed disks is made.
11
Bornassi, Saeed, Christian Maria Firrone, and Teresa Maria Berruti. "Vibration Parameters Estimation by Blade Tip-Timing in Mistuned Bladed Disks in Presence of Close Resonances." Applied Sciences 10, no. 17 (August 27, 2020): 5930. http://dx.doi.org/10.3390/app10175930.
Повний текст джерелаАнотація:
The present paper is focused on the post processing of the data coming from the Blade Tip-Timing (BTT) sensors in the case where two very close peaks are present in the frequency response of the vibrating system. This type of dynamic response with two very close peaks can occur quite often in bladed disks. It is related to the fact that the bladed disk is not perfectly cyclic symmetric and the so called “mistuning” is present. A method based on the fitting of the BTT sensors data by means of a 2 degrees of freedom (2DOF) dynamic model is proposed. Nonlinear least square optimization technique is employed for identification of the vibration characteristics. A numerical test case based on a lump parameter model of a bladed disk assembly is used to simulate different response curves and the corresponding sensors signals. The Frequency Response Function (FRF) constructed at the resonance region is compared with the traditional Sine fitting results, the resonance frequencies and damping values estimated by the fitting procedure are also reported. Accurate predictions are achieved and the results demonstrate the considerable capacity of the 2DOF method to be used as a standalone or as a complement to the standard Sine fitting method.
12
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.
Повний текст джерелаАнотація:
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.
13
Rivas-Guerra, A. J., M. P. Mignolet, and J. P. Delor. "Identification of Mistuning Characteristics of Bladed Disks From Free Response Data— Part II." Journal of Engineering for Gas Turbines and Power 123, no. 2 (June 9, 1999): 404–11. http://dx.doi.org/10.1115/1.1338950.
Повний текст джерелаАнотація:
The focus of the present two-part investigation is on the estimation of the dynamic properties, i.e., masses, stiffnesses, natural frequencies, mode shapes and their statistical distributions, of turbomachine blades to be used in the accurate prediction of the forced response of mistuned bladed disks. As input to this process, it is assumed that the lowest natural frequencies of the blades alone have been experimentally measured, for example in a broach block test. Since the number of measurements is always less than the number of unknowns, this problem is indeterminate in nature. In this second part of the investigation, the maximum likelihood method (ML) will first be revisited and a thorough assessment of its reliability in a wide variety of conditions, including the presence of measurement noise, different distributions of blade structural properties, etc., will be conducted. Then, a technique that provides a bridge between the two identification methods introduced in Part I, i.e., the random modal stiffnesses (RMS) and maximum likelihood (ML) approaches, will be presented. This technique, termed the improved random modal stiffnesses (IRMS) method is based on the maximum likelihood concepts but yields a mistuning model similar to that of the random modal stiffnesses technique. Finally, the accuracy of the RMS, ML, and IRMS methods in predicting the forced response statistics of mistuned bladed disks will be investigated in the presence of close blade alone natural frequencies.
14
Lastivka, Ivan. "RAISING GAS-DYNAMIC STABILITY MARGIN OF AXIAL AND CENTRIFUGAL COMPRESSOR STAGES BY MEANS OF VANED DIFFUSER BOUNDARY LAYER CONTROL / DUJŲ DINAMINIO STABILUMO RIBOS AŠINIO IR IŠCENTRINIO KOMPRESORIAUS PAKOPOSE DIDINIMAS ATLIEKANT STABILIZUOTO DIFUZORIAUS PARIBIO SLUOKSNIO KONTROLĘ." Aviation 15, no. 3 (October 4, 2011): 76–81. http://dx.doi.org/10.3846/16487788.2011.624262.
Повний текст джерелаАнотація:
Generalised research results that consider the upgradability of axial and centrifugal gas turbine engine compressors by means of gas-dynamic boundary layer control on bladed disks are demonstrated. Active and passive methods are used. Comparative analysis of the results has been carried out. The analysis is purposed to determine the influence of the flow circulation around the aerofoils on the performance of compressor single-row bladed disks with smooth blades and rough blades and under the condition that vortex generators are installed. An increase in the efficiency of aviation gas-turbine engines and in their gas-dynamic stability margin support leads to the enhancement of the parameters and performance of compressors: increase in loading of aerodynamic bladed disks, improvement of their economical efficiency, improvement of margin of the continuous flow around the compressor grids, etc. Airflow in the compressor grid is characterised by the flow region in the flow core and also by the flow regions in the wall boundary layers on the grid blades where shock waves, vortices, air swirls, and flow separation phenomena take place. The principle objective of the work is to research the possibilities of influence on the parameters of the elements of compressors and overall performance of gas-turbine engines via the methods of active and passive flow regulation. Active flow regulation is realised either by rendering the auxiliary gas mass to the blades boundary layer, or by suction (withdrawal) of the boundary layer (its part) from the surfaces of blades. Passive flow around regulation is characterised by influence on the boundary layer by means of energy redistribution in the flow itself. Santrauka Šiuo tyrimu siekiama nustatyti sparno profilio aptekejimo įtaką vienos eiles menčių kompresoriaus su lygiomis ir šiurkščiomis mentemis darbui, esant įdiegtiems sūkurio generatoriams. Pagrindinis darbo tikslas – ištirti kompresoriaus elementų ir bendro dujų turbininių variklių darbo įtaką parametrams, taikant pasyvų ir aktyvų srauto reguliavimo metodus. Padidinus dujų turbininių variklių našumą ir jų dujų dinamikos stabilumo ribas, pagereja kompresorių darbas ir parametrai: padideja aerodinaminių diskų su mentemis apkrova, jie tampa ekonomiškai našesni, padideja nepertraukiamo srauto riba aplink kompresoriaus plokšteles.
15
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.
Повний текст джерелаАнотація:
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.
16
Lemoine, E., D. Nélias, F. Thouverez, and C. Vincent. "Influence of fretting wear on bladed disks dynamic analysis." Tribology International 145 (May 2020): 106148. http://dx.doi.org/10.1016/j.triboint.2019.106148.
Повний текст джерела
17
PŮST, LADISLAV, and LUDĚK PEŠEK. "VIBRATION OF CIRCULAR BLADED DISK WITH IMPERFECTIONS." International Journal of Bifurcation and Chaos 21, no. 10 (October 2011): 2893–904. http://dx.doi.org/10.1142/s0218127411030210.
Повний текст джерелаАнотація:
The steady state response of a model of circular bladed disk with imperfection is investigated. Disk imperfection results from additional two groups of damping heads fixed on opposite ends of one diameter. These damping heads are introduced into the computing model as additional point mass, damping and stiffness. Such type of imperfection causes the bifurcation of double eigenfrequencies into pairs of close eigenfrequencies. The effect of imperfection is examined both numerically on three-dimensional nonrotating FE-model and analytically on a simplified split 2DOF model of rotating disk excited by single point harmonic force. Nonlinear friction connection is analyzed and equivalent linear damping coefficient is derived and used in the calculation procedure. It is shown that nonproportional distribution of damping strongly influences the high of resonance peaks. Some examples of response curves illustrate the dynamic properties of stationary and rotating disks with mass-damping-stiffness imperfection.
18
Petrov, E. P., and D. J. Ewins. "Generic Friction Models for Time-Domain Vibration Analysis of Bladed Disks." Journal of Turbomachinery 126, no. 1 (January 1, 2004): 184–92. http://dx.doi.org/10.1115/1.1644557.
Повний текст джерелаАнотація:
New efficient models have been developed to describe dynamic friction effects in order to facilitate analysis of the vibration of bladed disks in the time domain. These friction models describe friction forces occurring at contact interfaces under time-varying normal load variations, including cases of separation. The friction models developed allow one to take into account time-varying friction contact parameters, such as friction coefficient and contact stiffness coefficients. Anisotropy and variation of the friction characteristics over the contact surfaces are included in the proposed models. The capabilities of the new friction models are demonstrated. Analysis of the friction forces is performed for different motion trajectories and different time variations of the normal load, and the effects of anisotropy, variation in time of the friction characteristics and normal load variation are discussed. A numerical analysis of transient vibrations of shrouded blades using the new models is presented.
19
Lin, Chang-Sheng, Hung-Tse Chiang, Chuan-Hsing Hsu, Ming-Hsien Lin, Jui-Kai Liu, and Chi-Jeng Bai. "Modal Verification and Strength Analysis of Bladed Rotors of Turbine in Rated Working Conditions." Applied Sciences 11, no. 14 (July 8, 2021): 6306. http://dx.doi.org/10.3390/app11146306.
Повний текст джерелаАнотація:
The Top-pressure Recovery Turbine (TRT) uses the blast furnace gas generated in the iron and steel manufacturing process to push the turbine which drives the generator to generate electricity, and the generated electric energy is supplied to in-plant equipment. In this paper, we investigate the aerodynamic force, centrifugal force, and maximum stress on the structure of the TRT rotor in rated working conditions and the positions of occurrence using the Finite Element Method (FEM), as well as discuss the dynamic characteristics of bladed disks during TRT operation through Campbell and SAFE diagrams. To confirm the effectiveness of the finite element models, the mode shapes and natural frequencies in the FEA-based modal analysis of the TRT rotor will be captured and compared with those of the practical structures through the Experimented Modal Analysis (EMA). To verify the agreement between the mode shapes of the finite element analysis and those of the actual structure, the Modal Assurance Criterion (MAC) is introduced here to confirm the reliability of the finite element model. The stress distribution on the structure in the rotation is obtained by centrifugal force analysis. The TRT rotor is driven as the blast furnace top pressure pushes the moving blade; when the rotor rotates, the moving blade bears centrifugal and periodic aerodynamic forces. The stress distribution is investigated on the structure when these forces act simultaneously using aerodynamic analysis. To discuss whether the bladed disks will resonate with the external force under the operating conditions, Campbell and SAFE diagrams are used for evaluation, and the modal parameters obtained from the EMA are used to estimate the strength and durability of the blades. According to the analysis results when the TRT rotor is in working conditions, the fatigue failure may occur at the maximum stress existing on the dovetail slot.
20
Capiez-Lernout, E., and C. Soize. "Nonparametric Modeling of Random Uncertainties for Dynamic Response of Mistuned Bladed Disks." Journal of Engineering for Gas Turbines and Power 126, no. 3 (July 1, 2004): 610–18. http://dx.doi.org/10.1115/1.1760527.
Повний текст джерелаАнотація:
The random character of blade mistuning is a motivation to construct probability models of random uncertainties. Recently, a new approach known as a nonparametric model of random uncertainties, based on the entropy optimization principle, was introduced for modeling random uncertainties in linear and nonlinear elastodynamics. This paper presents an extension of this nonparametric model for vibration analysis of structures with cyclic geometry. In particular this probability model allows the blade eigenfrequencies uncertainties and the blade-modal-shape uncertainties to be modeled.
21
Petrov, E. P., K. Y. Sanliturk, and D. J. Ewins. "A New Method for Dynamic Analysis of Mistuned Bladed Disks Based on the Exact Relationship Between Tuned and Mistuned Systems." Journal of Engineering for Gas Turbines and Power 124, no. 3 (June 19, 2002): 586–97. http://dx.doi.org/10.1115/1.1451753.
Повний текст джерелаАнотація:
A new method for the dynamic analysis of mistuned bladed disks is presented. The method is based on exact calculation of the response of a mistuned system using response levels for the tuned assembly together with a modification matrix constructed from the frequency response function (FRF) matrix of the tuned system and a matrix describing the mistuning. The main advantages of the method are its efficiency and accuracy, which allow the use of large finite element models of practical bladed disk assemblies in parametric studies of mistuning effects on vibration amplitudes. A new method of calculating the FRF matrix of the tuned system using a sector model is also developed so as to improve the efficiency of the method even further, making the proposed method a very attractive tool for mistuning studies. Various numerical aspects of the proposed method are addressed and its accuracy and efficiency are demonstrated using representative test cases.
22
Picou, A., E. Capiez-Lernout, C. Soize, and M. Mbaye. "Robust dynamic analysis of detuned-mistuned rotating bladed disks with geometric nonlinearities." Computational Mechanics 65, no. 3 (November 12, 2019): 711–30. http://dx.doi.org/10.1007/s00466-019-01790-4.
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23
Daitong, Wei, Chen Yugang, Li Hongkun, and Zhang Xiaowen. "Real-time reconstruction method of full-field dynamic response of rotating bladed disks." Mechanical Systems and Signal Processing 188 (April 2023): 109953. http://dx.doi.org/10.1016/j.ymssp.2022.109953.
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Vargiu, P., C. M. Firrone, S. Zucca, and M. M. Gola. "A reduced order model based on sector mistuning for the dynamic analysis of mistuned bladed disks." International Journal of Mechanical Sciences 53, no. 8 (August 2011): 639–46. http://dx.doi.org/10.1016/j.ijmecsci.2011.05.010.
Повний текст джерела
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Bladh, R., M. P. Castanier, and C. Pierre. "Component-Mode-Based Reduced Order Modeling Techniques for Mistuned Bladed Disks—Part II: Application." Journal of Engineering for Gas Turbines and Power 123, no. 1 (April 2, 2000): 100–108. http://dx.doi.org/10.1115/1.1338948.
Повний текст джерелаАнотація:
In this paper, the component-mode-based methods formulated in the companion paper (Part I: Theoretical Models) are applied to the dynamic analysis of two example finite element models of bladed disks. Free and forced responses for both tuned and mistuned rotors are considered. Comprehensive comparisons are made among the techniques using full system finite element solutions as a benchmark. The accurate capture of eigenfrequency veering regions is of critical importance for obtaining high-fidelity predictions of the rotor’s sensitivity to mistuning. Therefore, particular attention is devoted to this subject. It is shown that the Craig–Bampton component mode synthesis (CMS) technique is robust and yields highly reliable results. However, this is achieved at considerable computational cost due to the retained component interface degrees of freedom. It is demonstrated that this problem is alleviated by a secondary modal analysis reduction technique (SMART). In addition, a non-CMS mistuning projection method is considered. Although this method is elegant and accurate, it is seen that it lacks the versatility and efficiency of the CMS-based SMART. Overall, this work shows that significant improvements on the accuracy and efficiency of current reduced order modeling methods are possible.
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Quaegebeur, Samuel, Benjamin Chouvion, and Fabrice Thouverez. "Nonlinear dynamic analysis of three-dimensional bladed-disks with frictional contact interfaces based on cyclic reduction strategies." International Journal of Solids and Structures 236-237 (February 2022): 111277. http://dx.doi.org/10.1016/j.ijsolstr.2021.111277.
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Li, Chaofeng, Shihua Zhou, Shuhua Yang, Xiang Ren, and Bangchun Wen. "Dynamic Characteristics of Blade-Disk-Rotor System with Structural Mistuned Features." Open Mechanical Engineering Journal 8, no. 1 (April 18, 2014): 138–43. http://dx.doi.org/10.2174/1874155x20140501008.
Повний текст джерелаАнотація:
The finite element method is adopted to establish the dynamical models of blade, bladed disk and blades-diskshaft assemblies. Based on the analysis of mistuned structure and the dynamic characteristics of model in different levels, it gives the vibration mode distribution of different models. The research shows that the characteristics of the bladed disk and shaft have a huge difference, where some modes are caused by the strongly split and coupled vibration. The mistuned effects are likely to cause different coupled vibrations of blades between the blades-disk model and the blades-disk-shaft model. Meanwhile, it shows the frequency separation and concentration, and misses the system mode and the local vibration, which bring some difficulties for designing the blade-rotor system. In this paper, the results may provide a certain reference for blade-rotor system design and diagnosis.
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Zhang, Hui, Tianyu Zhao, Hongyuan Zhang, Honggang Pan, and Huiqun Yuan. "Dynamic characteristics of mistuned bladed disk system under rub-impact force." Advances in Mechanical Engineering 12, no. 11 (November 2020): 168781402097306. http://dx.doi.org/10.1177/1687814020973064.
Повний текст джерелаАнотація:
In order to study the rubbing of the mistuned bladed disk system with variable thickness blades, an elastically supported shaft-variable thickness blades coupled finite element model is established in this paper. A new rubbing force model is proposed considering the variable thickness section characteristics and rotation effect of the variable thickness blade. A method of mistuned parameter identification is introduced which consists of static frequency testing of blades, dichotomy, and finite element analysis. Based on the finite element method, the mistuned bladed disk system is made dynamic analysis in full rubbing by applying the judgment load method. The dynamic response of the mistuned bladed disk system is discussed under different conditions. The results show that increasing the amount of mistuning will increase the system vibration. At high speeds, the impact force will be partially offset by centrifugal force. And the rubbing gap affects the form of rubbing. With the gap decreases, the system will change from intermittent rubbing to continuous rubbing. In addition, when the system is rubbed, due to energy dissipation and blade damping, the stress is transferred from the blade tip to the blade root and attenuated. In general, rubbing is a random complex nonlinear vibration process.
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Firrone, Christian M., Stefano Zucca, and Muzio M. Gola. "The effect of underplatform dampers on the forced response of bladed disks by a coupled static/dynamic harmonic balance method." International Journal of Non-Linear Mechanics 46, no. 2 (March 2011): 363–75. http://dx.doi.org/10.1016/j.ijnonlinmec.2010.10.001.
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Rajendran, P., N. Jamia, S. El-Borgi, and M. I. Friswell. "Wavelet Transform-Based Damage Identification in Bladed Disks and Rotating Blades." Shock and Vibration 2018 (October 17, 2018): 1–16. http://dx.doi.org/10.1155/2018/3027980.
Повний текст джерелаАнотація:
Blade vibration and blade clearance are effective diagnostic features for the identification of blade damage in rotating machines. Blade tip-timing (BTT) is a noncontact method that is often used to monitor the vibration and clearance of blades in a rotating machinery. Standard signal processing of BTT measurements give one blade response sample per revolution of the machine which is often insufficient for the diagnosis of damage. This paper uses the raw data signals from the sensors directly and employs a wavelet energy-based mistuning index (WEBMI) to predict the presence and locations of damage in rotating blades. The Lipschitz exponent is derived from the wavelet packet coefficients and used to estimate the severity of the damage. In this study, experiments were conducted to obtain BTT measurements on rotating blades at 100 rpm using three different sensors: an active eddy current sensor, a passive eddy current sensor, and an optical sensor. In addition, hammer excitation experiments were conducted for various added mass (damage) cases to compute the damage severity for a bladed disk. To simulate the damage experimentally in the bladed disk and rotating blades, masses were added to the blades to alter their dynamics and mimic the damage. The results indicate that the WEBMI can detect the presence and location of damage in rotating blades using measurements from common BTT sensors. To check the robustness of the proposed damage severity index, the experimental results were compared with numerical simulation for the bladed disk and showed good agreement.
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Kan, Xuanen, and Tuo Xing. "A novel mathematical model for the design of the resonance mechanism of an intentional mistuning bladed disk system." Mechanical Sciences 13, no. 2 (December 20, 2022): 1031–37. http://dx.doi.org/10.5194/ms-13-1031-2022.
Повний текст джерелаАнотація:
Abstract. Bladed disk systems with advanced functions are widely used in turbo-machineries. However, there are always deviations in physical dynamic properties between blades and blades due to the tolerance and wear in operation. The deviations will lead to vibration localization, which will result in high cycle fatigue and accelerate the damage of the bladed disk system. Therefore, many intentional mistuning patterns are proposed to overcome this larger local vibration. Previous studies show that intentional mistuning patterns can be used to reduce the vibration localization of the bladed disk. However, the determination of the resonance mechanism of the intentional mistuning bladed disk system is still an unsolved issue. In this paper, a novel mathematical model of resonance of an intentional mistuning bladed disk system is established. Mistuning of blades and energy resonance are included in this theoretical model. The method of the mechanical power of the rotating blade for one cycle is applied to obtain the resonance condition. By using this theoretical model, the resonance mechanism of an intentional mistuning bladed disk is demonstrated. The results suggest that the ideal results can be obtained by adjusting the intentional mistuning parameter. This paper will guide the design of the dynamic characteristics of the intentional mistuning bladed disk.
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Yuan, Hui Qun, Liang Zhang, and Lin Song. "Dynamics Characteristic Analysis of Deliberate Mistuned Bladed-Disk System in Compressor Based on Substructure Method." Applied Mechanics and Materials 141 (November 2011): 129–33. http://dx.doi.org/10.4028/www.scientific.net/amm.141.129.
Повний текст джерелаАнотація:
In this paper, based on the test data of blade static frequency and simulating blade deliberate mistuned by changing elastic modulus, a method combining dichotomy and finite element is presented which can identify elastic modulus parameters of mistuned blades. Then, when value of the frequency difference is 5Hz and 41Hz, dynamic characteristics of deliberate mistuned bladed-disk system are investigated separately under operating speed, on the basis of substructure method. Apply the exciting force of airflow on the fronts of blades tip. According to dynamic test results, it takes 4 as the excitation order. The analysis results show that with the mistuned frequency difference increasing, the largest amplitude of blade will decrease gradually. The deliberate mistuned scheme of large frequency difference as scheme Ⅱ is more effective than the small one as schemeⅠto reduce the vibration of bladed disk system under working speed of 11300r/min. The analysis results are consistent with the dynamic test ones.
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Ferhatoglu, Erhan, and Stefano Zucca. "On the non-uniqueness of friction forces and the systematic computation of dynamic response boundaries for turbine bladed disks with contacts." Mechanical Systems and Signal Processing 160 (November 2021): 107917. http://dx.doi.org/10.1016/j.ymssp.2021.107917.
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Rusanov, A. V., G. Yu Martynenko, K. V. Avramov, V. O. Varlahov, and V. G. Martynenko. "DETERMINATION OF RUPTURE SOURCES OF TURBINE BLADE PACKETS AT PERFORMANCE OF FORENSIC EXAMINATIONS." Theory and Practice of Forensic Science and Criminalistics 17 (November 29, 2017): 297–307. http://dx.doi.org/10.32353/khrife.2017.37.
Повний текст джерелаАнотація:
The technique ofdetermination of rupture sources of the turbine blades packets, which can be used at performance of forensic expertise is suggested. Its distinctive feature is completeness of the account of the various factors concerning different areas of the applied physics, such as gas dynamics, heat conductivity, thermoelasticity, static and dynamic strength. The following series of calculations was made for acknowledgement of rupture sources of bladed disk. I. Calculation of a viscous compressed subsonic current. II. Calculation periodic gas-dynamic loads operating on the blades. III. Calculation of a non-stationary stress-strain state of the bladed disk under the action of periodic forces. The technique is based on use of the numerical methods of gas dynamics and dynamic strength. The steam current through a turbomachine step calculated with the help of model of the viscous, compressedfluid. The forced vibrations of the bladed disk under the action of the aerodynamic loads are analyzed by the numerical integration of the nonlinearfinite elements design model. Four cases are considered for the numerical calculations of the stress-strain state. I. The clearance in the disk slots are not accounted and the vibrations under the action ofgas-dynamic loads from ideal directing device are investigated. II. The clearance in the disk slots are not accounted and the vibrations under the action of gas- dynamic loads from defective directing device are investigated. III. The clearance in the disk slots are taken into account and the vibrations under the action of gas-dynamic loads from ideal directing device are investigated. IV. The clearance in the disk slots are taken into account and the vibrations under the action of gas-dynamic loads from defective directing device are investigated. It’s established that a source of rupture ofworking blades of a regulating step of a compartment of a high pressure of the steam turbine is damage of blades of the directing device.
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de Andrade, Donizeti, and David A. Peters. "Coupling of a State-Space Inflow to Nonlinear Blade Equations and Extraction of Generalized Aerodynamic Force Mode Shapes." Applied Mechanics Reviews 46, no. 11S (November 1, 1993): S295—S304. http://dx.doi.org/10.1115/1.3122648.
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The aeroelastic stability of helicopter rotors in hovering flight has been investigated by a set of generalized dynamic wake equations and hybrid equations of motion for an elastic blade cantilevered in bending and having a torsional root spring to model pitch-link flexibility. The generalized dynamic wake model employed is based on an induced flow distribution expanded in a set of harmonic and radial shape functions, including undetermined time dependent coefficients as aerodynamic states. The flow is described by a system of first-order, ordinary differential equations in time, for which the pressure distribution at the rotor disk is expressed as a summation of the discrete loadings on each blade, accounting simultaneously for a finite number of blades and overall rotor effects. The present methodology leads to a standard eigenanalysis for the associated dynamics, for which the partitioned coefficient matrices depend on the numerical solution of the blade equilibrium and inflow steady-state equations. Numerical results for a two-bladed, stiff-inplane hingeless rotor with torsionally soft blades show the importance of unsteady, three-dimensional aerodynamics in predicting associated generalized aerodynamic force mode shapes.
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Thresher, R. W., A. D. Wright, and E. L. Hershberg. "A Computer Analysis of Wind Turbine Blade Dynamic Loads." Journal of Solar Energy Engineering 108, no. 1 (February 1, 1986): 17–25. http://dx.doi.org/10.1115/1.3268046.
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The flapping motion of a single wind turbine rotor blade has been analyzed and equations describing the flapping motion have been developed. The analysis was constrained to allow only flapping motions for a cantilevered blade, and the equations of motion are linearized. A computer code, called FLAP (Force and Loads Analysis Program), to solve the equations of motion and compute the blade loads, has been completed and compared to measured loads for a 3-bladed downwind turbine with stiff blades. The results of the program are presented in tabulated form for equidistant points along the blade and equal azimuth angles around the rotor disk. The blade deflection, slope and velocity, flapwise shear and moment, edgewise shear and moment, blade tension, and blade torsion are given. The deterministic excitations considered in the analysis include wind shear, tower shadow, gravity, and a prescribed yaw motion.
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Bladh, R., M. P. Castanier, and C. Pierre. "Effects of Multistage Coupling and Disk Flexibility on Mistuned Bladed Disk Dynamics." Journal of Engineering for Gas Turbines and Power 125, no. 1 (December 27, 2002): 121–30. http://dx.doi.org/10.1115/1.1498267.
Повний текст джерелаАнотація:
The effects of disk flexibility and multistage coupling on the dynamics of bladed disks with and without blade mistuning are investigated. Both free and forced responses are examined using finite element representations of example single and two-stage rotor models. The reported work demonstrates the importance of proper treatment of interstage (stage-to-stage) boundaries in order to yield adequate capture of disk-blade modal interaction in eigenfrequency veering regions. The modified disk-blade modal interactions resulting from interstage-coupling-induced changes in disk flexibility are found to have a significant impact on (a) tuned responses due to excitations passing through eigenfrequency veering regions, and (b) a design’s sensitivity to blade mistuning. Hence, the findings in this paper suggest that multistage analyses may be required when excitations are expected to fall in or near eigenfrequency veering regions or when the sensitivity to blade mistuning is to be accounted for. Conversely, the observed sensitivity to disk flexibility also indicates that the severity of unfavorable structural interblade coupling may be reduced significantly by redesigning the disk(s) and stage-to-stage connectivity. The relatively drastic effects of such modifications illustrated in this work indicate that the design modifications required to alleviate veering-related response problems may be less comprehensive than what might have been expected.
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Filsinger, D., J. Szwedowicz, and O. Scha¨fer. "Approach to Unidirectional Coupled CFD–FEM Analysis of Axial Turbocharger Turbine Blades." Journal of Turbomachinery 124, no. 1 (February 1, 2001): 125–31. http://dx.doi.org/10.1115/1.1415035.
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This paper describes an approach to unidirectional coupled CFD–FEM analysis developed at ABB Turbo Systems Ltd. Results of numerical investigations concerning the vibration behavior of an axial turbocharger turbine are presented. To predict the excitation forces acting on the rotating blades, the time-resolved two-dimensional coupled stator–rotor flow field of the turbine stage was calculated. The unsteady pressure, imposed on the airfoil contour, leads to circumferentially nonuniform and pulsating excitation forces acting on the rotating bladed disk. A harmonic transformation of the excitation forces into the rotating coordinate system of a single blade was elaborated and the complex Fourier amplitudes were determined. The bladed rotor was modeled by a single symmetric segment with complex circumferential boundary conditions. With respect to different nodal diameter numbers, free vibration analyses of the disk assembly were then effectively performed. For calculated resonance conditions, the steady-state responses of the turbocharger bladed disk were computed. By using this coupled CFD–FEM analysis, the dynamic loading of the turbine blades can be determined in the design process.
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Zhao, Li, Haosui Zhang, Yibing Liu, and Chao Zhou. "Nonlinear Dynamic Characteristics of Multidisk Rod Fastening Rotor with Axial Unbalance Mass Distribution." Shock and Vibration 2022 (March 8, 2022): 1–14. http://dx.doi.org/10.1155/2022/8094476.
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During long-term operation, the blades of rod fastening rotor are very prone to fault and may cause uneven axial mass distribution. The dynamic characteristics of a multidisk rod fastening rotor with axial unbalance mass distribution are studied. A four-disk rod fastening rotor model was established by the lumped mass method. The mass unbalance on different disks was used to simulate blade faults in different parts, and nonlinear factors such as oil film force and disk contact effect were considered. The fourth-order Runge-Kutta method was used to solve the model, and the spectrum and axis trajectory curves were obtained. The influence of fault location and rotating speed on rotor dynamic characteristics was analysed when there were blade faults on two disks. The results show that a large, unbalanced mass will bring strong nonlinear characteristics. The rod fastening rotor may be in different motion states at different rotating speeds. When the fault position of two disks changes, the changes of bearing spectrum, axis trajectory, and phase difference have regularity. The results can provide a theoretical basis for condition monitoring and fault diagnosis of rod fastening rotor.
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Panning, Lars, Walter Sextro, and Karl Popp. "Spatial Dynamics of Tuned and Mistuned Bladed Disks with Cylindrical and Wedge-Shaped Friction Dampers." International Journal of Rotating Machinery 9, no. 3 (2003): 219–28. http://dx.doi.org/10.1155/s1023621x03000198.
Повний текст джерелаАнотація:
One of the main tasks in the design of turbomachines like turbines, compressors, and fans is to increase the reliability and efficiency of the arrangement. Failures due to blade cracks are still a problem and have to be minimized with respect to costs and safety aspects. To reduce the maximum stresses, the blades can be coupled via friction damping devices such as underplatform dampers that are pressed onto the blade platforms by centrifugal forces. In this work, a method will be presented to optimize two different types of underplatform dampers in bladed disk applications with respect to a maximum damping effect.In practice, underplatform dampers with various geometric properties—cylindrical and wedge-shaped—are commonly used and lead to different contact conditions. A discretization of the contact areas between the blade platforms and the dampers is applied to be able to investigate nearly arbitrary contact geometries and spatial blade vibrations. The functionality of the two mentioned damper types has been studied in detail under different working conditions of the assembly. The advantages and disadvantages of both damper types are pointed out and strategies are presented to improve the damper design. In this context, the influence of mistuning effects is discussed in terms of statistical mistuning of the blades' natural frequencies due to manufacturing tolerances as well as systematical mistuning due to a deliberate slight variation of the blade masses or geometries.
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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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Lu, Zhenyong, Shun Zhong, Huizheng Chen, Yushu Chen, Jiajie Han, and Chao Wang. "Modeling and Dynamic Characteristics Analysis of Blade-Disk Dual-Rotor System." Complexity 2020 (January 25, 2020): 1–13. http://dx.doi.org/10.1155/2020/2493169.
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In this paper, a simplified dynamic model of a dual-rotor system coupled with blade disk is built, and the effects of blade parameters of an aircraft engine on the dynamic characteristics of a dual-rotor system are studied. In the methodology, the blade is simplified as a cantilever structure, and the dynamical equations are obtained by the means of a finite element method. The amplitude-frequency response curves and orbits of shaft centre-vibration shape diagram are used to analyze the effects of blade parameters on dynamic characteristics of a dual-rotor system. The results indicate that the properties of the blades have huge impacts on the critical speed and other dynamic characteristics of the system. With an increase of the length of the blade, the second-order critical speed decreases obviously, but the first-order critical speed is almost invariant; this means that the blades attached on the low-pressure compressor do not affect the first-order critical speed of the dual-rotor system. Meanwhile, note that the high-pressure rotor and low-pressure turbine rotor can excite the first-order resonance of the dual-rotor system, while the low-pressure compressor rotor can only excite the second-order resonance, and then the dynamic model of this six-point support dual-rotor system can further be simplified as a relatively independent single-rotor system with one disk and a four-support dual-rotor system with dual disks.
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Nikolayev, V. A. "Geometric, kinematic and dynamic parameters of the disc ripper." Russian Automobile and Highway Industry Journal 18, no. 5 (November 25, 2021): 476–87. http://dx.doi.org/10.26518/2071-7296-2021-18-5-476-487.
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Introduction. The unit of continuous action for the formation of the underlying layer is designed to increase labour productivity in the construction of roads and other objects, for the construction of which it is necessary to remove the upper layer of soil. For loosening of soil in the unit used bit-like working bodies. Often, disc working bodies are used to cut the soil. Therefore, the expediency of using passive discs in road-building technical means, in particular, in the unit of continuous action for the formation of the underlying layer of highways, is of practical interest. Despite the large number of works, a detailed analysis of the operation of passive disks was not made. Therefore, in order to compare the energy costs for cutting the soil with passive discs and chisel-shaped working bodies, it is necessary to make a theoretical analysis of the operation of passive disks. Analysis of the energy costs of the disk ripper cannot be carried out without having the approximate values of its geometric, kinematic and dynamic parameters.The method of research. As part of a continuous unit to form the underlying layer of roads, each disc would be clamped with soil on both sides and carried out clamped cutting. Therefore, a disk ripper is adopted for analysis, aggregated with a separate energy device. On the basis of the constructive layout, rational geometric parameters of the disk ripper are revealed. The method of calculation of its kinematic and dynamic parameters is developed. In particular, the method of determining the weighted average circumferental velocity of the disk, the angular velocity of the disk and the circumferental velocity of the point on the edge of the disk blade is considered. The modes of cutting the soil by various parts of the disk are considered.Results. On the basis of the developed technique, the dependence of the minimum diameter of the disk on the depth of soil development was revealed. The moment of resistance of the soil to the rotation of the disks is calculated. The horizontal and vertical component of soil resistance to the front disc carrying out clamped cutting and subsequent discs carrying out semi-clamped cutting of the soil are determined. The necessary thrust force of the energy device for cutting the soil with a disk ripper and the dependence of the thrust force of the energy device for cutting the soil on the depth of soil development were revealed. The performance of the unit, including the power device and the disk ripper, is calculated.Conclusion. Since as part of the unit of continuous action for the formation of the underlying layer of roads, the disks will carry out clamped cutting of the soil, for preliminary loosening of the soil with disks, it is more expedient to use a separate unit, including an energy device and a disk ripper. On the basis of the theoretical studies carried out, the necessary thrust force of the energy device for cutting the soil and the total traction force necessary to move the disc ripper were revealed. The performance of the unit is calculated. To compare the energy costs for cutting the soil with passive discs and chisel-shaped working bodies, it is necessary to make a theoretical analysis of the energy costs for the operation of passive disks.
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Yuan, Hui Qun, and Liang Zhang. "Dynamics Characteristic Analysis of Deliberate Mistuned Bladed-Disk System in Compressor Based on CMS Mothod." Advanced Materials Research 305 (July 2011): 192–97. http://dx.doi.org/10.4028/www.scientific.net/amr.305.192.
Повний текст джерелаАнотація:
In this paper first,a method combining dichotomy and finite element is presented which identify elastic modulus parameters of mistuned bladed based on the test data of blade static frequency and simulation blade deliberate mistuned by change elastic modulus.Then, dynamic characteristics of deliberate mistuned 10Hz and 41Hz bladed-disk system were analyzed in work rotating speed based on CMS mothod, respectively. The exciting force of airflow exert on costal margin of blade tip.According to dynamic test results,the incentive order is 4. The analysis results show that along with the mistuning frequency difference increases,the largest amplitude of blade is becoming smaller(except tuned system) , and scheme of large frequency difference 41Hz deliberate mistuned (scheme Ⅱ) better than scheme of small frequency difference 10Hz deliberate mistuned (scheme Ⅰ) for vibration reduction of bladed-disk system in work rotating speed for 11300r/min. The analysis results are consistent with the dynamic test results.
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Gastaldi, Chiara, Emanuele Grossi, and Teresa M. Berruti. "On the choice of contact parameters for the forced response calculation of a bladed disk with underplatform dampers." Journal of the Global Power and Propulsion Society 1 (June 20, 2017): 5D19RH. http://dx.doi.org/10.22261/5d19rh.
Повний текст джерелаАнотація:
AbstractUnderplatform dampers (UPDs) are still in use to reduce the vibration amplitude of turbine blades and to shift the position of resonant frequencies. The dynamics of blades with UPDs is nonlinear and the analysis is challenging from both the experimental and the numerical point of view. A key point in obtaining a predictive numerical tool is the choice of the correct contact parameters (contact stiffness and friction coefficient) that are required as input to the contact model. The paper presents different approaches to choose these parameters: the contact stiffness in normal and tangential direction are both calculated and measured. The calculation is based on the analytical models in literature, the measurements are carried out on a dedicated test rig. The friction coefficient is also measured. Test results of the forced response of the same bladed disk with UPDs are available for each blade, they come from an experimental campaign under controlled excitation and centrifugal force. The forced response of the bladed disk is not used as a mean to tune the contact parameters, but rather as a validation tool: the effect of the different choices of contact parameters in the code is highlighted by the comparison of the calculated and experimental forced response of the bladed disk.
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Liang, Zhi Chao, Jie Hong, Yan Hong Ma, and Tian Yuan He. "FEM Modeling Technology and Vibration Analysis of Flexible Rotor System." Applied Mechanics and Materials 226-228 (November 2012): 257–61. http://dx.doi.org/10.4028/www.scientific.net/amm.226-228.257.
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The low-pressure spool in a high-bypass ratio turbofan engine has its unique characteristics. The slightness rotor and the large lumped mass in blade and disk are the structural characteristics while the dynamic coupling between bladed-disk and shaft is the mechanical characteristic. This paper studies on the modeling technology of a flexible rotor system based on the finite element method (FEM). The equivalent-disk method, an equivalent principle of finite element modeling, is put forward. The blades are equivalent to a disk which can not only retain the structural and mechanical characteristics but also control the scale of the model and convert the periodic geometry into axisymmetric geometry. The results show that the equivalent-disk method is helpful to improve the modeling techniques of rotor system and can be used in engineering.
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Crawley, E. F., E. H. Ducharme, and D. R. Mokadam. "Analytical and Experimental Investigation of the Coupled Bladed Disk/Shaft Whirl of a Cantilevered Turbofan." Journal of Engineering for Gas Turbines and Power 108, no. 4 (October 1, 1986): 567–75. http://dx.doi.org/10.1115/1.3239948.
Повний текст джерелаАнотація:
The structural dynamics of a rotating flexible blade-rigid disk-flexible cantilevered shaft system is analytically and experimentally investigated. A simple analytical model yields the equations of motion expressed in the rotating frame, which show that the blade one nodal diameter modes dynamically couple to the rigid body whirling motion of the shaft-disk system. The blade modes higher than one nodal diameter are uncoupled from the shaft-disk dynamics. Nondimensionalization of the coupled equations of motion yield the criteria for the propensity and magnitude of the interaction between the bladed disk and shaft-disk modes. The analytical model was then correlated with the results of a structural dynamic experiment performed on the MIT Aeroelastic Rotor, a fan similar in design to a modern high bypass ratio shroudless turbofan. A special whirl excitation apparatus was used to excite both forward and backward asynchronous whirl, in order to determine the natural frequencies of the system. The agreement between the predicted and experimental natural frequencies is good and indicates the possibility of significant interaction of the one nodal diameter blade modes with the shaft-disk modes.
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Repetckii, Oleg, and Van Vinh Nguyen. "DYNAMIC CHARACTERISTICS ANALYSIS OF BLADED DISK TURBOMACHINES BASED ON INTENTIONAL MISTUNING." Perm National Research Polytechnic University Aerospace Engineering Bulletin, no. 62 (2020): 61–70. http://dx.doi.org/10.15593/2224-9982/2020.62.07.
Повний текст джерелаАнотація:
To increase technical level of energy turbomachine in modern turbomachinery, high reliability and durability of structures are required in the design, manufacture and operation of turbomachine. Any change geometry, mass, material properties of the bladed disk of turbomachine in the design is called mistuning parameters. With a small value of mistuning blades can significantly increase amplitude, displacement or stresses of the blades structures. So, analysis influence of the effect mistuning parameters on the dynamic characteristics in the field of turbomachine is an important and urgent task. This article analyzes the effect intentional mistuning of the axial bladed disk turbomachine in order to reduce forced response due to low-order engine excitation. The maximum value forced response of rotor blades turbomachine with mistuning parameters is usually much more than that of the tuned rotors. An increase level mistuning of this critical value actually leads to a decrease magnifications of the forced response. Thus, the actual work has been introducing some degree of intentional mistuning in the design to achieve these purposes. In this paper, we study the effectiveness of intentional mistuning at the design stage bladed disk turbomachine, which is introduced into the rotor design by changing the nominal mass of the blades in harmonic Формаls.
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Yang, Faming, Yongmin Yang, Haifeng Hu, Fengjiao Guan, Guoji Shen, Suiyu Chen, and Zifang Bian. "Extraction of Features due to Breathing Crack from Vibration Response of Rotated Blades considering Tenon Connection and Shroud Contact." Shock and Vibration 2019 (July 29, 2019): 1–20. http://dx.doi.org/10.1155/2019/8729620.
Повний текст джерелаАнотація:
Cracks are common failures of aeroengine rotated blades. Online monitoring of rotated blades through their vibration to identify cracks early in various working conditions is significant for operational safety. Breathing crack is a practical form of early cracks and results in nonlinear vibration response. Tenon connection and shroud contact are common structures in aeroengine rotated blades, which can also lead blades to vibrate nonlinearly and seriously interfere online identification of early cracks. Thus, it is important to extract vibration features due to breathing crack considering these two structures. Firstly, a blade with tenon and shroud is simplified and a lumped parameter model of the bladed disk is built. Then, dry friction and coupling force on a blade are analyzed and dynamics equations of the lumped parameter model are established. Next, the stiffness of the blade trunk with a breathing crack is analyzed. Finally, the vibration response of blade trunks with the occurrence of breathing crack is analyzed in time and frequency domains by numerical simulation. Effective features due to breathing crack for online identification are extracted. 2x components of spectrums can be the criterion to judge whether breathing crack occurs. Besides, by comparing the changes in vibration amplitudes with 1x component peaks of spectrums, the cracked blade trunk can be distinguished. These findings can provide important theoretical guidance for online identification of early cracks in aeroengine rotated blades.
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Zheng, Hua-Dong, Bo Zhang, Sheng-Bin Wang, and Guan-Zheng Zhou. "Effects of Blade Numbers on Wind-Induced Fatigue Lives of Straight-Bladed Vertical-Axis Wind-Turbine Tower Bases." Metals 12, no. 2 (February 11, 2022): 321. http://dx.doi.org/10.3390/met12020321.
Повний текст джерелаАнотація:
Vertical-axis wind turbines (VAWTs) are being reconsidered as a complementary technology to the more commercially used horizontal-axis wind turbines (HAWTs) because of their economical installation and maintenance. The selection of the blade numbers is one of the crucial concerns for VAWTs. This study focuses on the effects of the blade numbers on the fatigue lives of VAWT tower bases subjected to wind loading. Three straight-bladed VAWTs, with the same solidity ratios but different blade numbers, varying from two to four, were designed. The aerodynamic loading incurred by the VAWTs was computed using the corrected double-disk multistreamtube (DMS) model. The dynamic equations of the turbine systems were solved using the explicit central difference method. Then, a fatigue assessment model, including the crack-initiation and crack-propagation stages, was developed for the turbine tower bases. The results indicate that the three- and four-bladed VAWTs always presented better performances than the two-bladed VAWT in terms of the fatigue life. Moreover, increasing the number of blades from two to three improves the fatigue life of the tower base more than increasing it from three to four at lower wind speeds, while the latter is the more effective way to improve the tower-base fatigue life at higher wind speeds.