Готові списки джерел за темами / Coupled lateral torsional vibration

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Добірка наукової літератури з теми "Coupled lateral torsional vibration"

Автор: Grafiati

Опубліковано: 10 березня 2023

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Статті в журналах з теми "Coupled lateral torsional vibration"

An, Xue Li, Dong Xiang Jiang, Ming Hao Zhao, and Chao Liu. "Numerical Analysis of Coupled Lateral and Torsional Vibrations of a Vertical Unbalanced Rotor." Applied Mechanics and Materials 20-23 (January 2010): 352–57. http://dx.doi.org/10.4028/www.scientific.net/amm.20-23.352.

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A model for the coupled lateral and torsional vibrations of a vertical unbalanced rotor is developed. The equation of motion is obtained using Lagrangian dynamics without considering the external actuating forces and torque. The equation showed coupling and nonlinear interaction between the rotor lateral and torsional vibrations. Most of the earlier work on coupled vibrations has been done for the horizontal rotor model. The coupled vibrations for a vertical rotor have not been reported in the past. An attempt is made to reveal dynamic characteristics of vertical rotor. The results of the simulation showed the coupled between torsional and lateral vibrations is induced by mass eccentricity. Coupled vibrations have appeared in the start period of the vibration. After a transient vibration process, the vibrations are not coupling. The lateral vibration becomes equal amplitude with shafting speed. And the torsional vibration keeps on attenuating until it stops. When the vibration is coupled, the coupling effect on which torsional vibration to lateral vibration is evident. But there’s no coupling effect on the lateral to the torsional. It is also shown that for some operational parameters, the controlling action may excite large lateral vibrations due to coupling with the torsional motion.

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Ren, Fushen, Baojin Wang, and Suli Chen. "Nonlinear Modeling and Qualitative Analysis of Coupled Vibrations in a Drill String." International Journal of Bifurcation and Chaos 28, no. 10 (September 2018): 1850119. http://dx.doi.org/10.1142/s0218127418501195.

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A coupled model for axial/torsional/lateral vibrations of the drill string is presented, in which the nonlinear dynamics and qualitative analysis method are employed to find out the key factors and sensitive zone for coupled vibration. The drill string is simplified as an equivalent shell under axial rotation. After dimensionless processing, the mathematical model for coupled axial/torsional/lateral vibrations of the drill string is obtained. The Runge–Kutta–Fehlberg method is employed for the numerical simulation, and the rules that govern the changing of the torsional and axial excitation are revealed. And the stability domains of the explicit Runge–Kutta method are analyzed. Furthermore, the suggestions for field applications are also presented. It is demonstrated by simulation results that the lateral/axial/torsional vibrations exist simultaneously and couple with each other. The system will obtain a stable period motion with an axial excitation zone before the coupled vibration in the three directions, and continue to increase the axial excitation to cause the coupled vibration easily. The torsional excitation of the drill string mainly contributes to the coupled vibration in the three directions when in a specific rotation speed zone. The system is more likely to obtain a periodic motion through adjusting the torsional excitation out of this zone.

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Choi, S. H., J. Glienicke, D. C. Han, and K. Urlichs. "Dynamic Gear Loads Due to Coupled Lateral, Torsional and Axial Vibrations in a Helical Geared System." Journal of Vibration and Acoustics 121, no. 2 (April 1, 1999): 141–48. http://dx.doi.org/10.1115/1.2893956.

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In this paper we investigate the rotordynamics of a geared system with coupled lateral, torsional and axial vibrations, with a view toward understanding the severe vibration problems that occurred on a 28-MW turboset consisting of steam turbine, double helical gear and generator. The new dynamic model of the shaft line was based on the most accurate simulation of the static shaft lines, which are influenced by variable steam forces and load-dependent gear forces. The gear forces determine the static shaft position in the bearing shell. Each speed and load condition results in a new static bending line which defines the boundary condition for the dynamic vibration calculation of the coupled lateral, torsional and axial systems. Rigid disks and distributed springs were used for shaft line modeling. The tooth contact was modeled by distributed springs acting normally on the flank surfaces of both helices. A finite element method with distributed mass was used for lateral and torsional vibrations. It was coupled to a lumped mass model describing the axial vibrations. The forced vibrations due to unbalances and static transmission errors were calculated. The eigenvalue problem was solved by means of a stability analysis showing the special behavior of the coupled system examined. The calculation was successfully applied, and the source of the vibration problem could be located as being a gear-related transmission error. Several redesign proposals lead to a reliable and satisfactory vibrational behavior of the turboset.

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Krott, Matthew J., Edward C. Smith, and Christopher D. Rahn. "Coupled and Multimode Tailboom Vibration Control Using Fluidic Flexible Matrix Composite Tubes." Journal of the American Helicopter Society 64, no. 4 (October 1, 2019): 1–10. http://dx.doi.org/10.4050/jahs.64.042007.

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This paper covers the modeling and testing of a helicopter tailboom integrated with a fluidic flexible matrix composite (F2MC) damped vibration absorber. In an advance over previous work, the F2MC absorber presented in this paper treats a combination of tailboom lateral, torsional, and vertical vibrations. A finite element structural model of a laboratory-scale tailboom is combined with a model of attached F2MC tubes and a tuned fluidic circuit. Vibration reductions of over 75% in a coupled 26.8-Hz lateral bending/torsion tailboom mode are predicted by the model and measured experimentally. These results demonstrate that F2MC vibration control is viable at higher frequencies and for more complex vibration modes than previous research had explored. A new absorber with a fluidic circuit that targets two tailboom vibration modes is designed and experimentally tested. On the lab-scale tailboom testbed, the absorber with this circuit is shown to provide vibration reductions of over 60% in both a 12.2-Hz vertical mode and a 26.8-Hz lateral bending/torsion mode. Using this new absorber, vertical and lateral/torsion mode damping are achieved with almost no added weight relative to a purely vertical absorber.

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Hu, Zehua, Jinyuan Tang, and Siyu Chen. "Analysis of coupled lateral-torsional vibration response of a geared shaft rotor system with and without gyroscopic effect." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 232, no. 24 (January 22, 2018): 4550–63. http://dx.doi.org/10.1177/0954406217753457.

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Анотація:

A torsional gear dynamic model and a coupled lateral-torsional geared shaft rotor dynamic model are developed considering the time-varying mesh stiffness, backlash, and static transmission error excitation. The torsional dynamic transmission error responses gained from the torsional gear dynamic model and coupled lateral-torsional geared shaft rotor dynamic model are compared. The natural frequencies and mode shapes of the geared shaft rotor system are given and the frequency whirling behaviors are analyzed based on the Campbell diagram. The influences of gyroscopic effects of rotating shafts and meshing gear rotors on the lateral-torsional vibration responses of the geared shaft rotor system are talked about and some conclusions are drawn. (1) The coupled lateral-torsional geared shaft rotor dynamic model could reflect the jump phenomenon of dynamic responses near the critical speed of the gear pair as well as the pure torsional gear dynamic model and it can give more vibration features caused by geared shaft and bearings than the torsional gear dynamic model. (2) When the gear pair is set in the midpoint of the shaft, the influences of the gyroscopic effects on the gear pair’s lateral vibration responses are light and only can be observed near the high critical speeds. However, when the displacements from the gear body to the bearings are not the same, the influences of the gyroscopic effects on the lateral and torsional vibration responses are obvious and can be located both near the low critical speeds and the high critical speeds corresponding to the forward and backward whirling frequency. (3) The influences of the gyroscopic effects on the lateral and torsional vibration responses of the pinion are more obvious than those on the vibration responses of the gear. In addition, relative to the torsional vibration, the lateral vibration of the gear pair is more easily affected by the gyroscopic effect.

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Yang, Xu Juan, Guang Heng Xu, Zhao Jun Li, and Ru Gui Wang. "Dynamic Modeling and Response Analysis of Lateral-Torsional Coupling Vibration of the Slewing Mechanism of a Hydraulic Excavator." Advanced Materials Research 753-755 (August 2013): 1755–59. http://dx.doi.org/10.4028/www.scientific.net/amr.753-755.1755.

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A lateral-torsional coupled vibration model of the slewing mechanism of a hydraulic excavator is developed with consideration of the effect of lateral vibration and torsional vibration of sun gear and planetary gear on mesh displacement, the mesh stiffness of gear pairs, the bearing stiffness of the planetary and the coupling relationship of two stage planetary gear trains. The dynamic response of the slewing mechanism of a hydraulic excavator is obtained. Compared to the pure torsional vibration, the lateral-torsional vibration model is more reasonable.

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Karri, Seshendra Kumar Venkat, and Sree Krishna Sundara Siva Rao Bollapragada. "Influence of lateral vibrations on the whirling characteristics of gear-pinion rotor system." Journal of Vibration and Control 18, no. 11 (October 19, 2011): 1624–30. http://dx.doi.org/10.1177/1077546311423064.

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Анотація:

The proposed work presents a methodology to analyze the influence of lateral vibrations on the whirling characteristics of a rotor-bearing system. A complex variable approach, which is proposed for the analysis of a single rotor system, is very powerful for this purpose. The approach is expanded to the analysis of a combined rotor system to apply it to the gear system analysis. The bearing stiffness and shaft flexibility of the geared rotor system are taken into account in two ways. With regard to the rotor effect, the frequency response functions are obtained for both torsional motions and coupled lateral-torsional motions. By obtaining the differences in the frequency responses of both the models, the effect of neglecting rotor effects in gear dynamics simulation is studied. The lateral stiffness of the system, which reflects the shaft and bearing stiffness, is considered to make a strong lateral and torsional motion coupling. It is shown that the lateral vibrations have considerable effect when the natural frequencies of the lateral vibration and torsional vibration are close to each other, which is expected. The effect of lateral-torsional coupling on gear dynamics is discussed based on the response of the system.

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Shen, X. Y., J. H. Jia, M. Zhao, and J. P. Jing. "Coupled torsional-lateral vibration of the unbalanced rotor system with external excitations." Journal of Strain Analysis for Engineering Design 42, no. 6 (August 1, 2007): 423–31. http://dx.doi.org/10.1243/03093247jsa304.

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The coupled torsional-lateral model of the rotor system is set up and governing equations are derived using the Lagrange approach with six degrees of freedom. The gyroscopic effect and gravity are included. Two kinds of unbalance, namely static unbalance and dynamic unbalance, are considered in the rotor system. Torsional and lateral motions are subjected to external excitations. Through numerical simulation, the developed model is used and the coupled torsional-lateral vibrations of the unbalanced rotor system under external excitations are investigated. Some new phenomena are found and discussed.

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Choy, F. K., Y. K. Tu, J. J. Zakrajsek, and D. P. Townsend. "Effects of Gear Box Vibration and Mass Imbalance on the Dynamics of Multistage Gear Transmission." Journal of Vibration and Acoustics 113, no. 3 (July 1, 1991): 333–44. http://dx.doi.org/10.1115/1.2930190.

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Анотація:

The objective of this paper is to present a comprehensive approach to analyze the dynamic behavior of multi-stage gear transmission systems with the effects of gear box induced vibrations and rotor mass-imbalances. The modal method, using undamped frequencies and planar mode shapes, is used to reduce the degree of freedom of the system. The various rotor-bearing stages as well as the lateral and torsional vibrations of each individual stage are coupled through localized gear mesh tooth interactions. Gear box vibrations are coupled to the gear stage dynamics through bearing support forces. Transient and steady state dynamics of lateral an torsional vibrations of the geared system are examined in both time and frequency domains. Vibration signature analysis techniques will be developed to interpret the overall system dynamics and individual modal excitations under various operating conditions. A typical 3- staged geared system is used as an example. Effects of mass imbalance and gear box vibrations on the system dynamic behavior are presented in terms of modal excitation functions for both lateral and torsional vibrations. Operational characteristics and conclusions are drawn from the results presented.

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Zhou, Shihua, Zhaohui Ren, Guiqiu Song, and Bangchun Wen. "Dynamic Characteristics Analysis of the Coupled Lateral-Torsional Vibration with Spur Gear System." International Journal of Rotating Machinery 2015 (2015): 1–14. http://dx.doi.org/10.1155/2015/371408.

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A sixteen-degree-of-freedom (16-DOF) lumped parameter dynamic model taking into account the gravity, eccentricity, bearing clearance, transmission error, and coupled lateral-torsional vibration is established. Based on the dynamical equation, the dynamic behaviors of the spur gear rotor bearing system are investigated by using Runge-Kutta method. The research focuses on the effect of rotational speed, eccentricity, and bearing clearance and nonlinear response of the coupled multibody dynamics is presented by vibration waveform, spectrum, and 3D frequency spectrum. The results show that the rotational frequency of the driven gear appears in the driving gear, and the dynamic characteristics of gears have obvious differences due to the effects of the gear assembly and the coupled lateral-torsional vibration. The bearing has its own resonance frequency, and the effect of the variable stiffness frequency of the bearings should be avoided during the system design. The results presented in this paper show an analysis of the coupled lateral-torsional vibration of the spur gear system. The study may contribute to a further understanding of the dynamic characteristics of such a spur gear rotor bearing system.

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Більше джерел

Дисертації з теми "Coupled lateral torsional vibration"

Perera, Ittapana. "Theoretical and experimental study of coupled torsional-lateral vibrations in rotor dynamics." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ38558.pdf.

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Kim, Yong Y. "Flexural-Torsional Coupled Vibration of Rotating Beams Using Orthogonal Polynomials." Thesis, Virginia Tech, 2000. http://hdl.handle.net/10919/32616.

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Dynamic behavior of flexural-torsional coupled vibration of rotating beams using the Rayleigh-Ritz method with orthogonal polynomials as basis functions is studied. The present work starts from a review of the development and analysis of four basic types of beam theories: the Euler-Bernoulli, Rayleigh, Shear and Timoshenko and goes over to a study of flexural-torsional coupled vibration analysis using basic beam theories. In obtaining natural frequencies, orthogonal polynomials used in the Rayleigh-Ritz method are studied as an efficient way of getting results. The study is also performed for both non-rotating and rotating beams. Orthogonal polynomials and functions studied in the present work are : Legendre, Chebyshev, integrated Legendre, modified Duncan polynomials, the eigenfunctions of a pinned-free uniform beam, and the special trigonometric functions used in conjunction with Hermite cubics. Studied cases are non-rotating and rotating Timoshenko beams, bending-torsion coupled beam with free-free boundary conditions, a cantilever beam, and a rotating cantilever beam. The obtained natural frequencies and mode shapes are compared to those available in various references and results for coupled flexural-torsional vibrations are compared to both previously available references and with those obtained using NASTRAN finite element package.
Master of Science

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Judd, Clinton T. "LATERAL-TORSIONAL VIBRATION OF A SIDE-LOADED ROTOR WITH ASYMMETRIC SHAFT STIFFNESS." DigitalCommons@CalPoly, 2010. https://digitalcommons.calpoly.edu/theses/288.

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Using energy equations a four degrees of freedom analytical model is developed for a two-disk rotor with shaft stiffness asymmetry. A radial constant force is applied to the outboard disk to emphasize the effects of gravity or aerodynamic side loading. Special emphasis is placed on characterizing the lateral and torsional vibration trends associated with shaft asymmetry which may be used to identify failing shafts in operational rotor systems. Simulation reveals distinct patterns in lateral and torsional response, with strong dependencies on the magnitude of the side load, magnitude of the asymmetry and proximity of the lateral and torsional natural frequencies. Notable interaction is also observed between the lateral and torsional response. Lateral response peaks are found to correlate to torsional response peaks under some conditions. An experiment is performed to compare the response of a real system with the simulated model.

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Emery, Michael Aaron. "The effects of torsional-lateral coupling on the dynamics of a gear coupled rotor." Texas A&M University, 2005. http://hdl.handle.net/1969.1/4727.

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Анотація:

This thesis focuses on the torsional-lateral interactions seen in gear coupled rotors. Of particular interest are cases where the torsional stiffness parameters affect the lateral critical speeds and where lateral stiffness and damping parameters affect torsional critical speeds and amplitudes. A common procedure for critical speed calculations has been to solve lateral and torsional systems separately. This procedure is tested through an eigenvalue analysis. It is shown in this thesis, however, that torsional-lateral interactions play major roles in each other's critical speeds. Some research has seemingly uncoupled two lateral degrees of freedom from the gear system by choosing bearing forces and a coordinate system pointing along the line of action and normal to the line of action. This simplification method has been tested for cases when the lateral bearing stiffness becomes asymmetric. The force generated by a rotating imbalance also creates a variable moment arm as the center of mass rotates about the geometric center of the gear. This variable moment arm is commonly neglected, but is included in the last case study and its effects are displayed in the results section of this thesis.

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Che, Kar Suriani Binti. "Oscillatory behaviour and strategy to reduce drilling vibration." Thesis, Brunel University, 2017. http://bura.brunel.ac.uk/handle/2438/15831.

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Drill String dynamic behaviour during the oil drilling operation, was a major source for the failure of the Bottom Hole Assembly (BHA). The behaviour produced torsional vibration, which underpins the stick slip phenomena. Besides threatening the safety of the oil drilling process, such failure cause interruptions in the drilling operations and incurred high maintenance cost to the oil drilling company. This issue can be resolved with the implementation of the optimum control mechanism while operating the drill string. In this research, an optimum control mechanism was proposed to suppress the torsional vibration as well as mitigate the risk of stick slip phenomenon from occurring. The mechanism was proposed through a series of rigorous research strategies i.e. updated-mathematical equation modelling, experimentation and simulation. As the first step, a mathematical equation model describing system dynamics was derived to set the parameter of investigation. Representing the freedom torsional of the two degrees - conventional vertical drill string, the model was used to predict the frictional Torque On Bit (TOB) through non-linear friction force, denoting the ground-formation behaviour during drilling activity. Using a velocity feedback system, the drill-string oscillation was reduced while gradually increasing its velocity via gain scheduling method - allowing fast response to load disturbance. To avoid the motor torque from exceeding the maximum threshold, a Weight On Bit (WOB) was introduced. This approach remarks the novel contribution of this research. Next, an experiment on the preliminary test rig within a controlled laboratory set up was conducted. The rotary drill rig was assembled to identify the dynamics (i.e. parameters) of an individual part of the drill string. The results obtained were then applied in the drill string operation experiment, to identify the optimum control mechanism that can avoid the torsional vibration. To enable triangulation of results, a simulation was conducted by applying the same parameters obtained from the test rig experiment in the model- which is the optimum control mechanism that was proposed in this research to minimise torsional vibration, as well as reducing the chance of drill-string failure due to stick-slip phenomenon.

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INNOCENTI, ALICE. "Development of efficient rotordynamical models to study coupled lateral-torsional vibrations." Doctoral thesis, 2015. http://hdl.handle.net/2158/1002732.

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In this thesis an accurate, efficient and fully coupled model for the evaluation of the dynamical behaviour of complex multi-rotor systems is presented. The model has been conceived with the purpose of modelling complex rotors through a systematic and practical approach and with the goal of investigating the bending-torsional interaction in rotor vibrations. The model is based on a finite element rotordynamics formulation and it is able to deal with long rotors characterised by complex topology, such as rotor with distributed inertias or complex connections. This kind of rotor and the way in which they are modelled may deeply influence the predicted dynamics of the system with particular concern to the lateral-torsional vibrations coupling. Thus, through the developed model, complicated shaft-to-rotor connections or particular mounted parts, otherwise not representable with classical models, may be mathematically described. The proposed model represents a systematic and practical approach to the rotor dynamics modeling issue and its main contribution to the research topic of coupled lateral-torsional vibration in rotors is due to its general topology

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Lai, jyh shyi, and 賴志錫. "Chaotic Behaviors of Rotor-Bearing Systems due to Coupled Lateral-Torsional Vibration." Thesis, 1995. http://ndltd.ncl.edu.tw/handle/44519641347585381095.

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Wu, Jung-Fu, and 吳榮福. "Torsional-and-lateral-coupled vibration analysis of a shaft carrying an eccentric propeller." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/59467433705040127728.

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Анотація:

碩士
國立高雄海洋科技大學
輪機工程研究所
94
The object of this thesis is to study the vibration behaviour of the propulsive shafting system induced by a rotating marine propeller carrying single or multiple eccentric concentrated masses. To this end, the entire propulsive shafting system is firstly represented as a three-degree-of-freedom torsional-and-lateral-coupled vibration system. Then, the expressions for total kinetic energy and total potential energy of the entire propulsive shafting system are derived. Next, based on the theory of Lagrange’s equations, the equations of motion of the entire propulsive shafting system are derived and the mass matrix, damping matrix, stiffness matrix and external force vector of the entire vibrating system are determined. Finally, the forced vibration responses of the propulsion shafting system are obtained by solving the last equations of motion with Newmark direct integration method. Some factors closely relating to the current research topic, such as mass, total number and distribution of eccentric concentrated mass, etc, are investigated. From the numerical results, it is found that the influence of eccentric mass(es) of the propeller on the vibration characteristics of the propulsive shafting system is significant.

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Wu, Chia-Chun, and 吳佳峻. "Coupled Lateral and Torsional Vibrations of Micro-Drill Using Finite Element Method." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/t87ydp.

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Анотація:

碩士
國立交通大學
機械工程系所
103
Abstract In this research, the finite element formulation is developed to analyze the coupling lateral and torsional vibrations of the micro drill with high speed cutting. However, most of these researches treated the micro drill as a system with four degrees of freedom in each node point and assumed that it is rigid in the torsional direction. There are coupling effects when the lateral and torsional vibrations exist at the same time. In this thesis, our micro drill consist of the cylinder, conical beam and pre-twisted beam. And the flute part of the micro drill is modeled by the pre-twisted beam. For accuracy purpose, the micro drill is modeled by the Timoshenko beam. The dynamic equations of the micro drill system are formulated from the finite element model which consists of the effects of the unbalance force, axial force, and external torque. The five degrees of freedom model are used in performing dynamic analysis of micro drill system. The Newmark Integration method is adopted in this approach. Furthermore, we have written a program to do numerical analysis based on the mathematical model we derived. According to our analysis, the response of lateral and torsional vibrations are affected by each other when the system is under the unbalance force, the axial force, and the cutting torque.

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Cheng, Yu-Chun, and 鄭宇峻. "Wind Turnnel Investigation on the Lateral/Torsional Coupled Aeroelastic Behavior of Rectangular Prisms." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/32346988049448875222.

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Анотація:

碩士
淡江大學
水資源及環境工程學系
88
The high-rise building plays a major role in construction development of modern cities. The eccentricity of the structural system cannot be neglected in modern designs.Thus the effects of wind on high-rise buildings and the interactions between these two have become main research topics. In order to control the influence of wind , this research simplified the high-rise building into a 2-D rectangular section. In order to observe the aeroelastic responses of these rectangular cylinders, we applied the method of free vibration in the wind tunnel, used different depth-to-height ratios, changed the frequency ratios of vibration and torsion,used different damping ratios, and applied the control factor to obtain different eccentricities of the cylinders in the along-wind direction. The experimental results show that when the geometric center is located above the mass center, the fluctuating displacement decreases in the across-wind direction, and vice versa. Increases in the eccentricity enhance the relative changes, when the frequency ratio is close to1.0, the fluctuating displacement also increases, the damping ratio restrains the response, thus a high damping ratio reduces the fluctuating displacement.

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Частини книг з теми "Coupled lateral torsional vibration"

Matsushita, Osami, Masato Tanaka, Masao Kobayashi, Patrick Keogh, and Hiroshi Kanki. "Torsional Vibration and Related Coupled Vibration." In Vibrations of Rotating Machinery, 261–99. Tokyo: Springer Japan, 2019. http://dx.doi.org/10.1007/978-4-431-55453-0_9.

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Volpi, Lucas P., Daniel M. Lobo, and Thiago G. Ritto. "Coupled Lateral-Torsional Drill-String with Uncertainties." In Lecture Notes in Mechanical Engineering, 80–88. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-53669-5_6.

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Kelly, James M. "Coupled Lateral-Torsional Response of Seismically Isolated Buildings." In Earthquake-Resistant Design with Rubber, 101–30. London: Springer London, 1997. http://dx.doi.org/10.1007/978-1-4471-0971-6_6.

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Kelly, James Marshall. "Coupled Lateral-Torsional Response of Base-Isolated Buildings." In Earthquake-Resistant Design with Rubber, 57–67. London: Springer London, 1993. http://dx.doi.org/10.1007/978-1-4471-3359-9_6.

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Driver, R. A., and T. S. Wilkinson. "Coupled axial-torsional vibration in turbine generator rotors." In Rotordynamics ’92, 35–42. London: Springer London, 1992. http://dx.doi.org/10.1007/978-1-4471-1979-1_5.

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Zhang, Jun, Jian Wang, Xike Li, Ligang Yao, and Xianzeng Liu. "Lateral-Torsional-Coupled Model Based Dynamic Analyses of Spur Gears Under Time-Varying External Load Conditions with Surface Wear." In Nonlinear Systems and Complexity, 107–33. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-94301-1_5.

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Tanaka, K., T. Kondou, and O. Matsushita. "Calculations of lateral-torsional coupled vibration in AC motor-driven geared rotor system with mode synthesis approach." In 10th International Conference on Vibrations in Rotating Machinery, 799–808. Elsevier, 2012. http://dx.doi.org/10.1533/9780857094537.13.799.

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Zhan, Z., H. Liu, C. Xiang, Q. Yan, H. Li, W. Wei, and L. Xu. "Study of lateral and torsional vibration distribution of two-stage planetary gears based on vibration energy theory." In International Conference on Gears 2019, 1245–52. VDI Verlag, 2019. http://dx.doi.org/10.51202/9783181023556-1245.

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Kim, Dookie, Md Kamrul Hassan, Seongkyu Chang, and Yasser Bigdeli. "Nonlinear Vibration Control of 3D Irregular Structures Subjected to Seismic Loads." In Advances in Computer and Electrical Engineering, 103–19. IGI Global, 2016. http://dx.doi.org/10.4018/978-1-4666-9479-8.ch003.

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For the active control of three dimensional (3D) irregular structures subjected to seismic load, a new nonlinear model is discussed in this chapter. As well as geometric nonlinearity, material nonlinearity is also considered with a neuro-controller training algorithm, which is applied to a structure of multi degrees of freedom. For the control model, a dynamic assembly of two different motions is considered such as coupling between torsional and lateral responses of the structure and interaction between the structural system and the actuator. The training algorithm and the proposed control system of the structure are evaluated by the response simulation of the structure under the excitation of El-Centro 1940 earthquake. With linear and nonlinear stiffness, a 3D three story building structure is controlled by a trained neural network as an example. As additional parameters for the simulation control time delay, the incident angle of earthquakes is considered. The results show that the proposed control algorithm is efficient in the control of the structural vibration.

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Kim, Dookie, Md Kamrul Hassan, Seongkyu Chang, and Yasser Bigdeli. "Nonlinear Vibration Control of 3D Irregular Structures Subjected to Seismic Loads." In Civil and Environmental Engineering, 1631–45. IGI Global, 2016. http://dx.doi.org/10.4018/978-1-4666-9619-8.ch074.

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Тези доповідей конференцій з теми "Coupled lateral torsional vibration"

Rajagopalan, Vinayaka N., and John M. Vance. "Diagnosing Coupled Lateral-Torsional Vibrations in Turbomachinery." In ASME Turbo Expo 2008: Power for Land, Sea, and Air. ASMEDC, 2008. http://dx.doi.org/10.1115/gt2008-50125.

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Rotordynamic instability, commonly observed as subsynchronous vibration, is a serious problem that can cause heavy damage to a turbomachine or make it incapable of operation due to high vibration levels. However, all subsynchronous vibrations are not necessarily unstable. A way to quickly diagnose them would be helpful. In an earlier paper, the authors presented data from experiments that simulated various causes of sub-synchronous vibrations, some causes being genuine rotordynamic instabilities and some others being benign (stable), and identified ways to diagnose and classify the subsynchronous motions. In a continuation of the same study, subsynchronous vibrations due to coupled lateral-torsional effects are experimentally simulated, the objective being to signal-analyze these vibrations to find unique signatures that identify this cause and also be able to recognize if they are a true rotordynamic instability or not. To this end, a test rig was built with parallel shafts coupled by gears, driven by a DC motor at one end and loaded at the other end, to closely simulate a real-world machine. A torsional mathematical model for the test rig is also presented to predict its torsional natural frequencies. Experiments were conducted wherein the first torsional natural frequency was externally excited, with the shaft spinning at a higher speed. The result was a false sub-synchronous “instability” signal in the lateral measurements. A method to distinguish these vibrations from a genuine lateral non-synchronous instability is presented. Also, a new diagnostic method to classify the subsynchronous vibration as benign is elucidated.

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Sawicki, Jerzy T., George Y. Baaklini, and Andrew L. Gyekenyesi. "Coupled Lateral and Torsional Vibrations of a Cracked Rotor." In ASME Turbo Expo 2004: Power for Land, Sea, and Air. ASMEDC, 2004. http://dx.doi.org/10.1115/gt2004-54095.

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Rotor crack problems present a significant safety and loss hazard in nearly every application of modern turbomachinery, particularly in the power generation industry. However, early crack detection is not easily achieved during the operation of machinery. The difficulty is based on the fact that a crack produces an undetectable change in the overall structural response. This paper analyzes the coupling of torsional and lateral vibrations for an unbalanced cracked rotor. The rotor equations of motion for a system with cracked shaft, obtained using Lagrangian dynamics, show coupling and nonlinear interaction between the torsional and lateral vibrations. To investigate the effect of a transverse surface crack on the dynamic rotor response the breathing crack model was employed. By applying an external torsional excitation together with the excitation due to unbalance, signature responses were observed in the rotor vibration spectrum at sum and difference frequencies. These signature responses were due to the nonlinear effect of the crack. The observed phenomena, analytically defined here, offers a new methodology concerning crack detection and prognosis in rotors.

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Liu, Chao, and Dongxiang Jiang. "Experimental Study on Lateral and Torsional Vibration of Cracked Rotor With Torsional Excitation." In ASME Turbo Expo 2013: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/gt2013-94422.

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Crack failures in rotating machinery can result in catastrophic accidents, and they are are difficult to detect online. Condition monitoring is widely applied in field to detect changes of vibration, and form diagnostic features. However, effective features in vibration of the cracked rotor need more tests, especially validating the features with experiments. This work carried out an experimental study on cracked rotors in laboratory. The experiments are as following: (I) vibration of the rotor in normal condition is firstly tested, where lateral vibration and torsional vibration are measured; (II) torsional excitation is exerted on driven end of rotor system, and vibration characteristics of the rotor are tested; (III) cracked rotors are tested with transverse and slant cracks, respectively. With the measured signals, comparisons of vibrations in normal rotor and cracked rotors are carried out. The results show that, the transverse crack introduces more significant changes in 1X frequency and coupled frequency, while the slant crack employs larger changes in 2X frequency. And variation of phases of 1X frequency is presented. Also, the crack plays an impact on the torsional responses.

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Hong, Liu, and Jaspreet Singh Dhupia. "Modeling and Control of Coupled Torsional and Lateral Vibrations in Drill Strings." In ASME 2015 Dynamic Systems and Control Conference. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/dscc2015-9714.

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Excessive vibrations of the drill strings, e.g., the stick-slip vibration, are the primary cause of premature failures and drilling inefficiencies in oil well drilling. To investigate and suppress such vibrations, this paper studies the dynamics of drill strings using a lumped parameter model, in which both the torsional stick-slip and lateral vibrations are taken into consideration. The friction torque due to the downhole bit-rock interaction, which plays a key role in stick-slip vibration, is modeled as a hysteretic dry friction function. Simulated results of this developed model are shown to have a close qualitative agreement with the field observations in terms of stick-slip vibrations. Afterwards, a sliding mode controller is applied to mitigate the undesired vibrations of drill strings. A good control performance in suppressing the stick-slip phenomenon is demonstrated for the proposed controller. However, numerical simulations also demonstrate that the control action can excite lateral instability in the system, which can result in impacts between the drill collars and the borehole wall due to the large amplitude in lateral vibrations. Thus, a proper choice of the control parameters is essential to suppress the vibrations in the drill strings. The developed lumped parameter model describing the coupled torsional and lateral response in the controlled drill strings presented in this paper can be used to aid in offline tuning of those control variables.

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HUANG, SHIMIN, KE SONG, LEI JIANG, and HONGJIAN YI. "MULTI-MODE CONTROL OF COUPLED LATERAL-TORSIONAL VIBRATION OF ASYMMETRICAL TALL BUILDINGS." In Tall Buildings from Engineering to Sustainability - Sixth International Conference on Tall Buildings, Mini Symposium on Sustainable Cities, Mini Symposium on Planning, Design and Socio-Economic Aspects of Tall Residential Living Environment. WORLD SCIENTIFIC, 2005. http://dx.doi.org/10.1142/9789812701480_0026.

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Zhao, Jie, Hans DeSmidt, and Wei Yao. "Coupled vibration of nonlinear breathing cracked rotor in lateral, torsional, and longitudinal DOFs." In SPIE Smart Structures and Materials + Nondestructive Evaluation and Health Monitoring, edited by Tribikram Kundu. SPIE, 2015. http://dx.doi.org/10.1117/12.2084341.

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Chen, Chin-Shong, S. Natsiavas, and Harold D. Nelson. "Coupled Lateral-Torsional Vibration of a Gear-Pair System Supported by a Squeeze Film Damper." In ASME 1993 Design Technical Conferences. American Society of Mechanical Engineers, 1993. http://dx.doi.org/10.1115/detc1993-0032.

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Abstract This paper investigates the coupled lateral-torsional vibration of a gear-pair system supported by a cavitated squeeze film damper (SFD). Both steady state and transient dynamic characteristics of the system are analyzed. In order to gain insight into the dynamics of the system, the free vibration frequencies and modes of the linearized system are first determined. Then, the response of the nonlinear system is examined under mass unbalance and torque excitation. The trigonometric collocation method (TCM) is employed to obtain periodic steady-state responses. Direct integration is also used in order to verify TCM and capture transient response. A comparison of the steady state responses obtained with the present model by first considering only the lateral vibration and then including torsional effects demonstrates the need to include the coupling between lateral and torsional motion. Then, the effect of parameters such as gear mesh stiffness and damping, clearance-to-diameter ratio of the SFD and gear mass unbalance on the steady state response is also presented. It is found that the mass unbalance excites not only lateral-dominated modes of the coupled system but also torsional-dominated modes. Further numerical results show that the modes of the coupled system which are dominated by lateral motion can be attenuated by using a SFD, while the modes dominated by torsional motion can be substantially suppressed by gear mesh damping. Finally, the presence of multiple solutions and complex response is predicted in some frequency ranges.

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Zhang, Yatao, and Jari Nyqvist. "Rotor Instability Due to Coupled Effect of Lateral and Torsional Modes and Improper Bearing Design." In ASME 1997 Design Engineering Technical Conferences. American Society of Mechanical Engineers, 1997. http://dx.doi.org/10.1115/detc97/vib-4031.

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Abstract This paper deals with a special subsynchronous vibration problem, namely rotor instability caused by partly coupled effect of torsional and bending modes and partly improper bearing design. A theoretical model is presented to investigate such complicated vibration problem. The analysis shows that a single bending or torsional vibration analysis is not enough to predict the stability of a geared rotor system, which includes a turbine, a gear, a generator, several bearings, a squeeze film damper and stators. Either a bearing design, which gives stability in single lateral vibration analysis, cannot guarantee the stability if a torsional vibration mode is involved. This indicates that the bearing design plays much more significant role in a geared rotor system. The theoretical model has been successfully applied to a steam turbine set, which experienced such kind of subsynchronous vibration, by modifying the original bearing design.

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Kudo, Takeshi, Koki Shiohata, Osami Matsushita, Hiroyuki Fujiwara, Akira Okabe, and Shigeo Sakurai. "Experimental Study of Torsional-Bending Coupled Vibration of a Rotor System With a Bladed Disk." In ASME 2013 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/detc2013-12115.

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An experimental investigation was conducted to confirm the bending-torsion coupled vibration of a rotor system with a bladed disk. For a rotor with relatively long blades such as in the latest low-pressure steam turbines, coupled vibration with shaft torsional vibration represents the bladed disk natural frequency of a nodal diameter (k) of zero (umbrella mode). Today this well-known behavior is reflected in the design of steam turbine rotor systems to prevent the blade vibration resonance due to torque excitation caused by the electric power grid, a standard for which is proposed by ISO 22266-1. The bending-torsion coupled resonance of rotor systems occurs, however, under specific conditions due to rotor unbalance. When the rotor’s rotational speed (Ω) is equal to the sum/difference of the bending natural frequency (ωb) and torsional natural frequency (ωθ), namely, Ω = ωθ ± ωb, there is coupled resonance, which was experimentally observed with a rotor with a relatively simplified shape. In this study, the test apparatus for a flexible rotor system equipped with a shrouded bladed disk driven by an electric motor was constructed to confirm the vibration characteristics, by envisioning the bending-torsion coupled resonance as applied to actual rotor systems of turbo machinery. A radial active magnetic bearing (AMB) was employed to support the rotor by controlling bearing stiffness and damping, and applying lateral directional excitation of forward and backward whirl to the rotor. A servomotor was also equipped at the end of the rotor system to excite the torsional vibration. The resonance of a bladed disk with nodal diameter (k) of zero, which was coupled with the rotor’s torsional vibration, was observed under the above condition (Ω = ωθ − ωb) through AMB excitation of the rotor’s bending natural frequency. Conversely, the torsional excitation caused by the servomotor was confirmed as causing the coupled resonance of rotor bending vibration.

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Chen, Shilin, Chris Propes, Curtis Lanning, and Brad Dunbar. "Mechanisms and Mitigation of 3D Coupled Vibrations in Drilling with PDC Bits." In SPE Annual Technical Conference and Exhibition. SPE, 2021. http://dx.doi.org/10.2118/205904-ms.

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Abstract In this paper we present a new type of vibration related to PDC bits in drilling and its mitigation: a vibration coupled in axial, lateral and torsional directions at a high common frequency (3D coupled vibration). The coupled frequency is as high as 400Hz. 3D coupled vibration is a new dysfunction in drilling operation. This type of vibration occurred more often than stick-slip vibration. Evidences reveal that the coupled frequency is an excitation frequency coming from the bottom hole pattern formed in bit/rock interaction. This excitation frequency and its higher order harmonics may excite axial resonance and/or torsional resonance of a BHA. The nature of 3D coupled vibration is more harmful than low frequency stick-slip vibration and high frequency torsional oscillation (HFTO). The correlation between the occurrence of 3D coupled vibration and bit design characteristics is studied. Being different from prior publications, we found the excitation frequency is dependent on bit design and the occurrence of 3D coupled vibration is correlated with bit design characteristics. New design guidlines have been proposed to reduce or to mitigate 3D coupled vibration.

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