Journal articles: 'ROTATION-VIBRATION MODEL'

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GUPTA, J. B. "NEW PERSPECTIVE IN ROTATION–VIBRATION INTERACTION." International Journal of Modern Physics E 22, no. 05 (May 2013): 1350023. http://dx.doi.org/10.1142/s0218301313500237.

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A linear relation for the level energy ratios in the ground band of even–even nuclei, based on the rotation–vibration expression, is derived and its application on a universal scale, including the O(6), E(5) and X(5) symmetries, is illustrated. A microscopic view of this relation and of the collective model is given. Also, an approximate relationship with single term power index formula E = aIb is demonstrated.

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Meyer, U. "The triaxial rotation vibration model in the Xe_Ba region." Progress in Particle and Nuclear Physics 38 (1997): 241–43. http://dx.doi.org/10.1016/s0146-6410(97)00031-8.

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Meyer, U., Amand Faessler, and S. B. Khadkikar. "The triaxial rotation vibration model in the XeBa region." Nuclear Physics A 624, no. 3 (October 1997): 391–400. http://dx.doi.org/10.1016/s0375-9474(97)00380-1.

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Liu, Xiaogang, Zhaoyu Wu, Jie Lu, and Jinli Xu. "Investigation of the Effect of Rotation Speed on Vibration Responses of Transmission System." MATEC Web of Conferences 256 (2019): 02019. http://dx.doi.org/10.1051/matecconf/201925602019.

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In the operating process, it is found the vibration of main reducer reaches a maximum value when certain types of vehicles are running at a speed around 4000 RPM. However, how the rotation speed of engine affects the vibration responses to automobile transmission system has not been investigated theoretically in details. To investigate this problem, the transmission system of automobile is simplified to a drive-final shaft system in this research, and a coupled vibration model of drive-final shaft system is developed. This model is used to simulate the vibration response to transmission system at different rotation speeds. Simulation results show that the torsional vibration responses reach the maximum when the rotation speeds are 3800 RPM and 4200 RPM and the vibration responses of pinion reach the maximum value when the rotation speeds are 4000 RPM and 4200 RPM. Moreover, finite element analysis is conducted to investigate the reason for this phenomenon. It is found that the torsional vibration responses reach the maximum value when the excitation frequency of engine is close to the resonance frequency of drive shafts. This research provides an effective method to analyse the vibration characteristics of automobile transmission system.

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Qin, Kang, Zhong Gen Xu, and Chang Gen Deng. "Analysis of Oxytropis Tower Structure with Model Method." Applied Mechanics and Materials 405-408 (September 2013): 1012–16. http://dx.doi.org/10.4028/www.scientific.net/amm.405-408.1012.

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Basic principles of the modal analysis are introduced. Model analysis of an oxytropis tower which is in an actual transmission tower system is carried out. Rationality of the modal is checked by results of the vibration periods. Meanwhile, analysis of vibration types of transformation and rotation under seismic action is also carried out, in order to provide reference data for further elastic-plastic analysis.

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Barts, B. I., E. V. Inopin, and N. A. Shlyakhov. "Quadrupole-octupole rotation-vibration model with self-consistent moments of inertia." Nuclear Physics A 448, no. 2 (January 1986): 253–70. http://dx.doi.org/10.1016/0375-9474(86)90090-4.

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Botero, D. F. Morales, L. C. Chamon, and B. V. Carlson. "Transition densities in the context of the generalized rotation-vibration model." Journal of Physics G: Nuclear and Particle Physics 44, no. 10 (August 21, 2017): 105102. http://dx.doi.org/10.1088/1361-6471/aa846e.

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Berezin, V. I., and M. D. �l'kin. "Valence-optical scheme and vibration-rotation model of a polyatomic molecule." Journal of Applied Spectroscopy 56, no. 3 (March 1992): 212–16. http://dx.doi.org/10.1007/bf00659097.

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Child, Mark S., and Qingshi Zhu. "Vibration—rotation Hamiltonian of tetrahedral molecules in the local-mode model." Chemical Physics Letters 184, no. 1-3 (September 1991): 41–44. http://dx.doi.org/10.1016/0009-2614(91)87161-4.

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Wang, Cheng Jun, Long Li, Xiang Rui Meng, Qiong Liu, and Tian Yu Zhang. "Kinetic Properties of Hybrid Vibration Screen with Two-Translation and One-Rotation." Key Engineering Materials 693 (May 2016): 356–63. http://dx.doi.org/10.4028/www.scientific.net/kem.693.356.

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To meet the need of modernized coal dressing, topology theory was used to build a kind of hybrid mechanism 2PRRR-R which can work as a main excitation mechanism of three freedom degree hybrid vibration screen with two-translation and one-rotation. Next, D′Alembert’s principle was introduced to establish a kinetic model of vibration screen frame and surface, and kinematic equations of directions of vibration screen frame and surface was achieved. Then, ADAMS was used to perform kinetic simulation of vibration screen, and kinetic parameters of the hybrid vibration screen was finally tested on multi-dimensional vibration screening test bench. The research shows that kinetic parameters’ numerical simulation of hybrid vibration screen with two-translation and one-rotation basically agrees with spot test value, which verifies the feasibility of the mechanism design, that the screen frame is of two motion freedom, that screen surface is of three motion freedom degree, that the rotation of the screen surface is relatively independent and controllable. The research provides further study of kinetic properties and development of hybrid vibration screen with two-translation and one-rotation with workable reference.

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Luo, Yin, Shouqi Yuan, Yue Tang, Jianping Yuan, and Jinfeng Zhang. "Modeling Optimal Scheduling for Pumping System to Minimize Operation Cost and Enhance Operation Reliability." Journal of Applied Mathematics 2012 (2012): 1–19. http://dx.doi.org/10.1155/2012/370502.

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Traditional pump scheduling models neglect the operation reliability which directly relates with the unscheduled maintenance cost and the wear cost during the operation. Just for this, based on the assumption that the vibration directly relates with the operation reliability and the degree of wear, it could express the operation reliability as the normalization of the vibration level. The characteristic of the vibration with the operation point was studied, it could be concluded that idealized flow versus vibration plot should be a distinct bathtub shape. There is a narrow sweet spot (80 to 100 percent BEP) to obtain low vibration levels in this shape, and the vibration also follows similar law with the square of the rotation speed without resonance phenomena. Then, the operation reliability could be modeled as the function of the capacity and rotation speed of the pump and add this function to the traditional model to form the new. And contrast with the tradition method, the result shown that the new model could fix the result produced by the traditional, make the pump operate in low vibration, then the operation reliability could increase and the maintenance cost could decrease.

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Gulshani, P. "A microscopic derivation of nuclear collective rotation–vibration model, axially symmetric case." Canadian Journal of Physics 94, no. 1 (January 2016): 79–88. http://dx.doi.org/10.1139/cjp-2015-0371.

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We derive a microscopic version of the successful phenomenological hydrodynamic model of Bohr–Davydov–Faessler–Greiner for collective rotation–vibration motion of an axially symmetric deformed nucleus. The derivation is not limited to small oscillation amplitudes. The nuclear Schrödinger equation is canonically transformed to collective coordinates, and then linearized using a constrained variational method. The associated constraints are imposed on the wavefunction rather than on the particle coordinates. This approach yields three self-consistent, time-reversal invariant, cranking-type Schrödinger equations for the rotation–vibration and intrinsic motions, and a self-consistency equation. For harmonic oscillator mean-field potentials, these equations are solved in closed forms and applied to the ground-state rotational bands in some axially symmetric nuclei. The results are compared with those of other models and related measured data.

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Kim, J. "Rotation Effects on Vibration of Structures Seen From a Rotating Beam Simply Supported off the Rotation Axis." Journal of Vibration and Acoustics 128, no. 3 (November 30, 2005): 328–37. http://dx.doi.org/10.1115/1.2172261.

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In rotating beams, the Coriolis force acts through the mass and rotary inertias of the beam. A rotating beam simply supported off the axis of rotation is used as an example to study effects of this Coriolis force on vibration of structures. By adopting such a simple model, mass- and rotary inertia-induced terms in the free vibration responses can be obtained in separate, closed forms. The effect of each of these terms on vibration characteristics of the rotating beam is discussed in relation to parameters such as nonrotating natural frequencies, the rotation speed, and the slenderness ratio. Practical implications of these results in analyses of rotating structures of other types are discussed, for example estimating the significance of rotary inertias in relation to the slenderness ratio and the rotation speed.

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Wu, Xue Min, and Wei Ping Huang. "An Analysis Method for Deepwater TTR Coupled Vibration of Parameter Vibration and Vortex-Induced Vibration." Applied Mechanics and Materials 284-287 (January 2013): 437–41. http://dx.doi.org/10.4028/www.scientific.net/amm.284-287.437.

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The long slender cylinder often suffers the high Reynolds number in ocean environment, and its dynamic characters and vortex shedding modes vary with a number of mechanical, physical and fluid–solid parameters.Considering the vertical vibration, caused by floating platform, of top tensioned riser (TTR), an analysis method for the coupled vibration of parameter excited vibration and vortex-induced vibration is presented in this paper. With the section rotation and shear deformation due to the bending large displacement of TTR, a coupled vibration model of parameter excited vibration and vortex-induced vibration is put forward. And the vortex-induced vibration (VIV) of a TTR for 1500m water depth is analyzed based on the model. The results show that the vertical vibration caused by floating platform increases transverse vibration displacement of TTR,especially in in-line direction.

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Souza, José W. N. de, Leonardo de A. Monteiro, Viviane C. dos Santos, Marcio P. da Silva, Isabela O. Lima, and Walisson M. Silveira. "Efficiency of anti-vibration gloves in soil preparation using a micro tractor." Revista Brasileira de Engenharia Agrícola e Ambiental 24, no. 6 (2020): 422–27. http://dx.doi.org/10.1590/1807-1929/agriambi.v24n6p422-427.

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ABSTRACT During the working day, agricultural machinery operators are often exposed to physical risks, such as vibration, which can compromise their health and performance. Micro tractors emit high levels of vibration, which mainly affect their hands and arms. Thus, this study aims at evaluating the efficiency of different glove models in reducing vibration transmitted by the micro tractor/rotary tiller assembly according to the operating velocity and the rotation of the rotary tiller rotor. A completely randomized block design was used in a 4 x 2 x 2 factorial arrangement with five replicates. The study analyzed three glove models (G1 and G2 anti-vibration models, and anti-impact model G3) and a control treatment under the same operating conditions, but without the use of protective equipment. The study was conducted at two operating velocities (V1 = 0.98 km h-1 and V2 = 1.6 km h-1) and two rotations of the rotary tiller rotor (R1 = 265 rpm and R2 = 520 rpm). None of the evaluated glove models reached the attenuation capacity required by the Occupational Hygiene Standard (Norma de Higiene Ocupacional - NHO 10) and, under some operating conditions, they raised the incident vibration levels, exceeding the values obtained when the work was performed without a protective equipment. Although the anti-impact model G3 and the anti-vibration model G2 did not reduce the transmitted vibration to the levels considered acceptable by NHO 10, the anti-impact G3 and anti-vibration G2 models showed better performance in the work performed at a velocity of 0.98 km h-1 and a rotation of 520 rpm of the rotary tiller rotor.

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Baylan, Mehmet, İhsan Uluer, Atalay Küçükbursa, and İsmail Maraş. "E2/M1 Multipole Mixing Ratios of 162Dy Nucleus in Rotation Vibration Model." Mathematical and Computational Applications 1, no. 1 (June 1, 1996): 154–58. http://dx.doi.org/10.3390/mca1010154.

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Iachello, F., S. Oss, and L. Viola. "Rotation-vibration interaction and Fermi resonances of HCCF in the vibron model." Molecular Physics 78, no. 3 (February 20, 1993): 561–75. http://dx.doi.org/10.1080/00268979300100391.

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Yao-Min, Di. "Rotation-Vibration Coupling in the Geometric Representation of the Interacting Boson Model." Chinese Physics Letters 19, no. 3 (February 22, 2002): 319–20. http://dx.doi.org/10.1088/0256-307x/19/3/310.

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Rykov, Sergey Alekseevich, Irina Kudryavtseva, and Sergey Vladimirovich Rykov. "VIBRATION MODULATION CAUSES AT ROTATION FREQUENCY IN ROTARY MACHINES." Akustika 32 (March 1, 2019): 151–57. http://dx.doi.org/10.36336/akustika201932151.

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The results of theoretical and experimental studies of the modulation of vibrations of rotary machines have been presented at rotation frequency. It has been shown that at the rotation frequency, the possible causes of the origin of the “side” spectral discrete components are the presence of a clearance and friction in bearing units. On the basis of the data obtained in the mathematical model, the diagnostic methods of the quality of functioning the bearing unit of rotary mechanisms are proposed.

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Ren, Fushen, Baojin Wang, Suli Chen, Zhigang Yao, and Baojun Bai. "Nonlinear Model and Qualitative Analysis for Coupled Axial/Torsional Vibrations of Drill String." Shock and Vibration 2016 (2016): 1–17. http://dx.doi.org/10.1155/2016/1646814.

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A nonlinear dynamics model and qualitative analysis are presented to study the key effective factors for coupled axial/torsional vibrations of a drill string, which is described as a simplified, equivalent, flexible shell under axial rotation. Here, after dimensionless processing, the mathematical models are obtained accounting for the coupling of axial and torsional vibrations using the nonlinear dynamics qualitative method, in which excitation loads and boundary conditions of the drill string are simplified to a rotating, flexible shell. The analysis of dynamics responses is performed by means of the Runge-Kutta-Fehlberg method, in which the rules that govern the changing of the torsional and axial excitation are revealed, and suggestions for engineering applications are also given. The simulation analysis shows that when the drill string is in a lower-speed rotation zone, the torsional excitation is the key factor in the coupling vibration, and increasing the torsional stress of the drill string more easily leads to the coupling vibration; however, when the drill string is in a higher-speed rotating zone, the axial excitation is a key factor in the coupling vibration, and the axial stress in a particular interval more easily leads to the coupling vibration of the drill string.

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Zhang, Li Rong. "Brief Analysis of Torsional Vibration of Vehicle Engine." Advanced Materials Research 694-697 (May 2013): 302–6. http://dx.doi.org/10.4028/www.scientific.net/amr.694-697.302.

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This article has established the machine shop truck with the engine shafting torsional vibration model, analyzed the engine rotation inertia and the torsional rigidity, established the engine crank torsional vibration equation, analyzed the machine shop truck to have the torsional vibration reason with the engine, proposed the engine torsional vibration reduced the method, has certain reference value to the engine design and the use.

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Pustka, Martin, and Pavel Šidlof. "Self-excited Vibration of Ink Rollers." ACC Journal 27, no. 1 (June 2021): 29–36. http://dx.doi.org/10.15240/tul/004/2021-1-003.

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A vibration having a character of self-excited chatter oscillation known from machine tools is observed during intermittent motion of ink rollers of offset printing machines. This vibration occurs under specific operating conditions and is often accompanied by an increased noise level. To explain this unusual vibration behavior, a simple analytical model of two rollers interaction is derived. The calculated oscillation is compared with the measurement of ductor roller displacement. The model results confirm the possibility of self-excited vibration development in the presence of viscous forces, negative damping effects and continuous supply of external energy from roller rotation.

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Lin, B. C., and A. S. Papageorgiou. "Demonstration of Torsional Coupling Caused by Closely Spaced Periods—1984 Morgan Hill Earthquake Response of the Santa Clara County Building." Earthquake Spectra 5, no. 3 (August 1989): 539–56. http://dx.doi.org/10.1193/1.1585539.

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The parameters of the dominant modes of vibration of the steel-framed Santa Clara County Office Building in San Jose, California, are determined using “the modal minimization method” for structural identification. The optimal estimates of the model parameters are determined by minimizing a selected measure-of-fit between the responses of the structure and the model. Two types of models are used: (1) A planar linear model with classical damping and (2) A three dimensional linear model consisting of rigid floor decks, where each floor is allowed three degrees of freedom - two orthogonal translations plus a rotation. The Santa Clara County Office Building continued vibrating in a free vibration manner with very low damping, long after the intense part of ground motion had ended. The records of its torsional motion exhibit a strong beating effect which is explained by the strong coupling of torsional and translational modes of vibration. Such a strong coupling of modes of vibration is attributed to the proximity of the value of torsional stiffness to that of translational stiffnesses.

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Halilbeşe, Akile Neşe, Cong Zhang, and Osman Azmi Özsoysal. "Effect of Coupled Torsional and Transverse Vibrations of the Marine Propulsion Shaft System." Journal of Marine Science and Application 20, no. 2 (June 2021): 201–12. http://dx.doi.org/10.1007/s11804-021-00205-2.

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AbstractIn this study, the coupled torsional–transverse vibration of a propeller shaft system owing to the misalignment caused by the shaft rotation was investigated. The proposed numerical model is based on the modified version of the Jeffcott rotor model. The equation of motion describing the harmonic vibrations of the system was obtained using the Euler–Lagrange equations for the associated energy functional. Experiments considering different rotation speeds and axial loads acting on the propulsion shaft system were performed to verify the numerical model. The effects of system parameters such as shaft length and diameter, stiffness and damping coefficients, and cross-section eccentricity were also studied. The cross-section eccentricity increased the displacement response, yet coupled vibrations were not initially observed. With the increase in the eccentricity, the interaction between two vibration modes became apparent, and the agreement between numerical predictions and experimental measurements improved. Given the results, the modified version of the Jeffcott rotor model can represent the coupled torsional–transverse vibration of propulsion shaft systems.

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Przysowa, Radosław. "The Analysis Of Synchronous Blade Vibration Using Linear Sine Fitting." Journal of KONBiN 30, no. 1 (December 1, 2014): 5–19. http://dx.doi.org/10.2478/jok-2014-0011.

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Abstract In Blade Tip Timing several sensors installed circumferentially in the casing are used to record times of arrival (TOA) and observe deflections of blade tips. This paper aims to demonstrate methodology of model-based processing of aliased data. It focuses on the blade vibration excited by the forces synchronous with engine rotation, which are called integral responses. The driven harmonic oscillator with single degree of freedom (SDOF) is used to analyse blade vibration measured by tip-timing sensors during engine deceleration. When integral engine order EO is known, the linear sine fitting techniques can be used to process data from sensors to estimate amplitude, phase and frequency of blade vibration in each rotation. The oscillator model is implemented in MATLAB and used to generate resonance curves and simulate blade responses observed with tip sensors, installed in the axial compressor. Generated TOA data are fitted to the sine function to estimate vibration parameters. The validated procedure is then employed to analyze real test data.

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Tseng, J. G., and J. A. Wickert. "Nonconservative Stability of a Friction Loaded Disk." Journal of Vibration and Acoustics 120, no. 4 (October 1, 1998): 922–29. http://dx.doi.org/10.1115/1.2893921.

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This paper investigates the vibration of an annular disk that is subjected to rotation and in-plane frictional traction distributed over a sector of the disk’s two faces. Technical applications include noise, vibration, and harshness in automotive and aircraft disk brakes, clutches, transmissions, and other rotating machine components. To the degree that the rotor-to-stator friction in such cases is directed along the disk’s deformable surface, it is treated here as a nonconservative follower-type load. The vibration model incorporates membrane stiffness which derives both from rotation, and from the stresses established as a result of friction. The plane stress state is determined in closed form as a Fourier series, and that solution is compared with the companion, but computationally intensive, results from finite element analysis. For the cases of sector-shaped and full annular loading, the vibration model predicts the critical mode, which is defined as the one that becomes dynamically unstable at the lowest friction level. Vibration modes and propagating waves that fall into opposite symmetry classes are shown to have opposite stability characteristics in the presence of frictional loading.

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Tian, Jing, Yan-Ting Ai, Cheng-Wei Fei, Feng-Ling Zhang, and Yat-Sze Choy. "Dynamic modeling and simulation of inter-shaft bearings with localized defects excited by time-varying displacement." Journal of Vibration and Control 25, no. 8 (January 29, 2019): 1436–46. http://dx.doi.org/10.1177/1077546318824927.

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To accurately describe the dynamic features of inter-shaft bearings with localized defect under operation, the dynamic model of inter-shaft bearing with localized defects was established with respect to time-varying displacement excitation. Based on fault simulations on a birotor experimental rig, the developed dynamic model of inter-shaft bearing is validated to have high accuracy (over 99%) when localized defects happen on inner and outer race with co- and counter-rotation, which indicates that the model can be adopted to simulate the faults of inter-shaft bearing instead of experiment. Through investigation of the square-root (SR) amplitudes of bearing vibration with different defect sizes, radial loads, and rotational directions, we find that the SR amplitudes of bearing vibration increase with increasing defect size and radial load for both co- and counter-rotation. The amplitudes of counter-rotation are larger than those of co-rotation for inner race and outer race, and the amplitude of inner race defect are larger than that of outer race defect for the same defect size or same radial load. This work reveals the SR variation of bearing vibration with localized surface defects under different defect sizes and radial loads, and accurately describes the dynamic characteristics of inter-shaft bearing with localized defects. The efforts of this study open a door to adopt a dynamic model in the future to evaluate and monitor the health condition of inter-shaft bearings in an aeroengine or other rotating machinery.

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Liu, Xing, Kazuteru Nagamura, and Kiyotaka Ikejo. "Simulation on the vibration characteristics of elliptical gears." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 227, no. 4 (July 16, 2012): 819–30. http://dx.doi.org/10.1177/0954406212454372.

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Elliptical gear drive is a typical non-circular gear drive, which can be used to transmit a variable-ratio rotation and power simultaneously. To date, elliptical gears are commonly used in automatic machinery, pumps, flow meters and printing presses. However, the vibration characteristics of elliptical gears have not been clarified yet. Due to the non-uniform rotation, the vibration of elliptical gear demonstrates particular characteristics, which should be paid attention to in practical application. This article presents a simulation method on the vibration characteristics of elliptical gears. The torsional vibration simulation model of elliptical gears is established and the simulation programme is developed. The particular gear mesh characteristics of elliptical gears are determined and both the inertial effects of the driving and driven sides of elliptical gears are taken into account in the simulation programme. By means of the simulation programme, two elliptical gear pairs which are a single elliptical gear pair and a double elliptical gear pair and, for comparison, two circular gear pairs which are of the same gear properties as the two elliptical gear pairs respectively are investigated. The torque variations, the rotation speed variations and the circumferential vibration accelerations of elliptical gears are analysed. Furthermore, the critical rotation speeds of tooth separation of elliptical gear drives are obtained and their relations with the load torques are also unveiled. Meanwhile the experiments of the test gears are carried out. The agreement of the simulative results and experimental results proves the validity of the simulation method on the vibration characteristics of elliptical gears proposed in this article.

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Xu, Lizhong, and Jinan Yang. "Vibration Analysis of a Two-Step Sine Movable Tooth Drive." Shock and Vibration 2018 (October 24, 2018): 1–11. http://dx.doi.org/10.1155/2018/4205273.

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In this study, a 3D model of a two-step sine movable tooth drive is developed in the UG software. The finite element model (FEM) analysis package, ANSYS, is used to calculate the natural frequencies and vibration modes of the drive system. The results show that the first twenty natural frequencies can be classified into five families, including the total system vibration mode, single-element vibration mode, two-element vibration mode, three-element vibration mode, and four-element vibration mode. The effects of the system parameters on the natural frequencies and the vibration modes are investigated. The track amplitude, the movable tooth radius, the radius of the movable tooth rotation, and the number of movable teeth affect the natural frequencies and vibration modes of the drive system.

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Chamon, L. C., and D. F. Morales Botero. "Folding-type coupling potentials in the context of the generalized rotation–vibration model." Journal of Physics G: Nuclear and Particle Physics 45, no. 3 (February 5, 2018): 035104. http://dx.doi.org/10.1088/1361-6471/aaa8b5.

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Leviatan, Amiram, and Michael W. Kirson. "Intrinsic and collective structure of an algebraic model of molecular rotation-vibration spectra." Annals of Physics 188, no. 1 (November 1988): 142–85. http://dx.doi.org/10.1016/0003-4916(88)90093-0.

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Sheng, Lianchao, Wei Li, Yuqiao Wang, Xuefeng Yang, and Mengbao Fan. "Rigid-flexible coupling dynamic model of a flexible planar parallel robot for modal characteristics research." Advances in Mechanical Engineering 11, no. 1 (January 2019): 168781401882346. http://dx.doi.org/10.1177/1687814018823469.

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The increasing applications of flexible parallel robots in industrial production have presented the advantages of light weight and high speed, but at the same time, the elastic vibration problem has emerged. By investigating the modal features of flexible parallel robots so as to suppress the elastic vibration, with pinned-pinned as flexible intermediate links boundary conditions, this article analyzes the rigid-flexible coupling dynamic mathematical model of the 3-RRR (3-Rotate-Rotate-Rotate) flexible planar parallel robot with flexible intermediate links. The effect of the extremity concentrated rotation inertia of flexible intermediate links is considered in the mathematical model. Besides, the effect of inertia and coupling force on the dynamic model and the first three-order vibration responses of flexible intermediate links were discussed based on the established model. The corresponding spectrum characteristics were studied using fast Fourier transform. Comparing the frequency characteristics obtained by theoretical model and modal experiment, it was found that the results obtained by the dynamic mathematical model are quite close to the test results. Less dynamic parameters make it convenient to carry out the control program.

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Wu, Bin, Shan Ping Yu, Yue Gang Luo, and Chang Jian Feng. "Varying Rotation Speed Bearing Fault Features and Extraction Method Based on Wavelet Packet." Applied Mechanics and Materials 644-650 (September 2014): 286–89. http://dx.doi.org/10.4028/www.scientific.net/amm.644-650.286.

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When bearing rotates, it comes with elastic hydrodynamic lubrication effect. Interaction between the effect and the bearing vibration leads to the change of lubricant film thickness, thus, contact stiffness of contact pair changes along with the rotation speed of the bearing, and then the resonance frequencies of the bearing system changes according to the rotation speed. In addition, the impact signal of varying speed bearing damage point no longer has the periodic characteristics. Based on the analysis of the bearing failure mechanism, this paper proposed a varying speed bearing vibration signal fault model, and also utilizes wavelet packet to extract the bearing fault signal by means of a variable speed rolling bearing vibration experiment table.

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Yayli, Mustafa Ö., Suheyla Y. Kandemir, and Ali E. Çerçevik. "Torsional vibration of cracked carbon nanotubes with torsional restraints using Eringen’s nonlocal differential model." Journal of Low Frequency Noise, Vibration and Active Control 38, no. 1 (December 26, 2018): 70–87. http://dx.doi.org/10.1177/1461348418813255.

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Free torsional vibration of cracked carbon nanotubes with elastic torsional boundary conditions is studied. Eringen’s nonlocal elasticity theory is used in the analysis. Two similar rotation functions are represented by two Fourier sine series. A coefficient matrix including torsional springs and crack parameter is derived by using Stokes’ transformation and nonlocal boundary conditions. This useful coefficient matrix can be used to obtain the torsional vibration frequencies of cracked nanotubes with restrained boundary conditions. Free torsional vibration frequencies are calculated by using Fourier sine series and compared with the finite element method and analytical solutions available in the literature. The effects of various parameters such as crack parameter, geometry of nanotubes, and deformable boundary conditions are discussed in detail.

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Yang, Wenguang, and Dongxiang Jiang. "An Improved Rigid Multibody Model for the Dynamic Analysis of the Planetary Gearbox in a Wind Turbine." Shock and Vibration 2016 (2016): 1–18. http://dx.doi.org/10.1155/2016/9742673.

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This paper proposes an improved rigid multibody model for the dynamic analysis of the planetary gearbox in a wind turbine. The improvements mainly include choosing the inertia frame as the reference frame of the carrier, the ring, and the sun and adding a new degree of freedom for each planet. An element assembly method is introduced to build the model, and a time-varying mesh stiffness model is presented. A planetary gear study case is employed to verify the validity of the improved model. Comparisons between the improvement model and the traditional model show that the natural characteristics are very close; the improved model can obtain the right equivalent moment of inertia of the planetary gear in the transient simulation, and all the rotation speeds satisfy the transmission relationships well; harmonic resonance and resonance modulation phenomena can be found in their vibration signals. The improved model is applied in a multistage gearbox dynamics analysis to reveal the prospects of the model. Modal analysis and transient analysis with and without time-varying mesh stiffness considered are conducted. The rotation speeds from the transient analysis are consistent with the theory, and resonance modulation can be found in the vibration signals.

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Luo, Liang, Weimin Zhang, Haonan Sui, and Jürgen Fleischer. "An Electromechanical Co-Simulation Model Based on Lumped Parameter Model of Ball Screw Feed Drive System." MATEC Web of Conferences 237 (2018): 03007. http://dx.doi.org/10.1051/matecconf/201823703007.

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The continuous search for efficiency put forward higher requests to the machine tool for high speed and high acceleration, which makes the large-size and lightweight-designed feed drive system more likely to produce vibration during high-speed and high-acceleration feed operation. Ball screw feed system is the most widely used linear drive system in the field of industrial automation. Electromechanical Co-Simulation for ball screw feed drive dynamics is an important technique for solving vibration problems occurs in the feed motion. In view of the shortcomings of the current dynamic simulation model in the study of vibration of ball screw feed drive system, taking a ball screw feed drive system test bench as an example, an electromechanical co-simulation model based on the lumped parameter model of ball screw feed drive system was built up in this paper. Firstly, based on the axial and rotation vibration integrated dynamic modeling method of ball screws, the lumped parameter model of ball screw feed system was established. Secondly, through the integration of the simulation model of semi-closed-loop cascade control system and the lumped parameter model of ball screw feed drive system, an electromechanical co-simulation model was built up. Simulation result shows that, the co-simulation model of ball screw feed drive system can predict the vibration occurs in the feed operation caused by the servo controller, ball screw feed system or the coupling between them.

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Zhu, XiaoHua, and Jun Jing. "Improving the drilling performance of hole enlargement via optimized operation." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 229, no. 9 (July 28, 2014): 1562–77. http://dx.doi.org/10.1177/0954406214545819.

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The severe vibration experienced by the bottom hole assembly (BHA) in the process of hole enlargement when drilling (HEWD) is the major cause for deteriorated drilling performance. A dynamic model of the system of reamer near pilot bit (RNB)-HEWD-BHA including the drillstring and drill collar is formulated with the finite element method. Based on the dynamic analysis and some project cases of hole enlargement, the relationship between operating rotation speed and dynamic characteristics of RNB-HEWD-BHA is discussed. The results show that “the optimum operating rotation speed” exists to this kind of BHA, and the dynamic characteristics of this BHA such as the rate of penetration (ROP), vibration, and safety can be improved effectively when the optimum operating rotation speed works. Furthermore, this paper offers a more scientific and objective method, the Fuzzy Synthetic Evaluation Model, to make a comprehensive evaluation of drilling performance of RNB-HEWD-BHA at different operating rotation speeds. These evaluation results will guide the operator to make more reasonable drilling operation plan to enlarge the hole efficiently and safely.

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Chen, Dongju, Na Li, Ri Pan, and Jihong Han. "Analysis of aerostatic spindle radial vibration error based on microscale nonlinear dynamic characteristics." Journal of Vibration and Control 25, no. 14 (May 2, 2019): 2043–52. http://dx.doi.org/10.1177/1077546319845429.

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This paper presents a method of predicting the radial rotary error of an aerostatic spindle based on the microscale-effect to investigate the influence of gas film fluctuation on the rotation accuracy of the aerostatic spindle. First, the gas bearing of the spindle is simplified as a spring-damping system with two degrees of freedom perpendicular to each other. Additionally, the aerostatic spindle bearing-rotor system is established by considering the forced vibration and deflection vibration of the rotor. Subsequently, the microscale-effect is introduced into the dynamic model of the gas film flow, and the dynamic Reynolds equation of the gas film is established in the microscale. Moreover, the nonlinear dynamic stiffness and dynamic damping coefficient are obtained by the perturbation method. The nonlinear dynamic parameters in the microscale are introduced into the dynamic model of the bearing-rotor system and all the vibration errors are obtained. By comparison with the conventional case, it is found that the spindle gyration error increased and that the response delay occurred when the microscale-effect is considered. Moreover, the influence of the supply pressure and speed on the vibration of the spindle is also analyzed. An experiment measuring the spindle rotation error is carried out. The experimental results reveal that the prediction method of the nonlinear spindle rotation error in the microscale is more accurate, and that the errors are 5.8% and 9.6%.

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Dhouib, S., R. Hbaieb, F. Chaari, M. S. Abbes, T. Fakhfakh, and M. Haddar. "Free vibration characteristics of compound planetary gear train sets." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 222, no. 8 (August 1, 2008): 1389–401. http://dx.doi.org/10.1243/09544062jmes870.

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In this study, a plane model of a compound planetary gear train (CPGT) is proposed in order to study its free vibration characteristics. Two translations and one rotation are considered for each element (sun, carrier, ring-1, ring-2, and planets) of the CPGT. The contact between the teeth in mesh is modelled by linear springs with stiffness called gearmesh stiffness. The phasing between these stiffness is taken into account. Using Lagrange formulation, the equation of motion is derived. Starting from the eigenvalue problem of the system, the influence of the planets’ number and position, and the effect of the gyroscopic phenomena on the free vibration of the CPGT are studied. The natural modes are classified into three groups: translational (the carrier, ring 1, and sun have pure modal translational deflection with no rotation), rotational (the carrier, ring 1, and sun have pure modal rotational deflection with no translation), and planets’ modes (only the planets have a modal deflection). It was found that the change of the planets’ angular position does not affect this classification. On the other hand, the study of the influence of the carrier rotation speed show that the gyroscopic effect separates the repeated translational modes into distinct ones. The obtained results are much important in the design process in order to avoid critical operating conditions which lead to undesirable vibrations.

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Liu, Guan-Chen, Li Xu, Jie Li, Qiang Sun, Zong-Qiang Liu, and Hai-Wen Chen. "Simulation of Abrasion Characteristics of Polar Ship Seawater Pipelines under the Coupling of Ice Particles and Vibration." Applied Sciences 10, no. 4 (February 17, 2020): 1349. http://dx.doi.org/10.3390/app10041349.

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Under the erosion of seawater–ice two-phase flow, seawater in pipelines of polar ships can cause the pipeline failures that threaten the safety of navigations. The discrete phase model (DPM) and erosion wear model (EWM) were established by using the computational fluid dynamics (CFD) method for numerical analysis of the 90° elbow with relatively severe erosion. This paper explores the erosion effect of pipelines under different conditions and puts forward optimal measures for pipeline protection. Compared with the existing multiphase flow research, the novelty of this study is that vibration conditions are considered and parameters such as two-phase flow velocity, ice packing factor (IPF), ice particle diameter and ice particle rotation characteristics are combined with vibration conditions. Combined with the comprehensive analysis of erosion effects of static pipelines, a general law of seawater pipeline wear under vibration is obtained. The results show that pipeline wear under vibration is more serious than under static conditions. Under static conditions, the wear of the same section in the pipeline increases with the increases of two-phase flow velocity and IPF. However, under vibration conditions, when the velocity is less than 3 m/s, the wear of the pipeline has no significant change, while when the velocity is over 3 m/s, the wear rate increases significantly. The particle diameter has little effect on the wear of static pipes, but under the vibration condition, the pipe wear rate decreases with the increase of particle diameter, and it starts to stabilize when the diameter exceeds 0.3 mm. If the rotation characteristics of ice particles are taken into account, the wear rate along the pipeline is significantly higher than that without particle rotation.

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Shi, Yao Chen, Zhan Guo Li, and Xiu Guang Yang. "The Study of Arc Teethed Automotive Synchronous Belt's Transmission Stability." Advanced Materials Research 915-916 (April 2014): 277–80. http://dx.doi.org/10.4028/www.scientific.net/amr.915-916.277.

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The vibration of belt affected the transmission stability of automotive synchronous belt. The mathematical model of longitudinal vibration was established through analyzing the longitudinal vibration of automotive synchronous belt. Developed the vibration dynamic measurement device, aiming at RU style arc teethed synchronous belt transmission process, measured the variety of amplitude over time at the middle of the belt span obtained the rules of amplitude and frequency change along with the rotation speed. It is of certain importance to improving the transmission stability of arc teethed synchronous belt.

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Wang, Feng, Zhiqiang Wu, Yajie Li, and Yuancen Wang. "Transverse nonlinear vibration of the eccentric rotor in a 12/8 switched reluctance motor." Engineering Computations 37, no. 8 (April 8, 2020): 2711–33. http://dx.doi.org/10.1108/ec-03-2019-0107.

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Purpose To investigate transverse vibration of the eccentric rotor in a 12/8 poles switched reluctance motor (SRM), a transverse analytical vibration model is built by finite element method (FEM) under the interaction of radial magnetic resultant and vibration displacement. External forces, including radial magnetic resultant and centrifugal force, are also derived in detail, according to the variation of airgap and current and other intermediate parameters with rotation angle. Design/methodology/approach The transverse vibration response of the eccentric rotor including radial magnetic resultant and vibration displacement is solved by Newmark-β method, after inputting the currents of three phase windings under angle position control strategy. The basic characteristics of radial magnetic resultant and vibration displacement are reflected in time and frequency domain. Findings The magnetic resultant vector of the eccentric rotor presents multi-petals star geometric shape. The frequency distribution of magnetic resultant relates to rotation speed, current waveform and the least common multiple of the stator and rotor teeth. However, the frequency distribution of the vibration displacement also relates closely to the first-order critical whirl speed of the rotor. When the rotor is running at certain speeds, it will display superharmonic resonance and show abundant displacement locus. Originality/value By using this analytical model and solving process proposed in this paper, the nonlinear coupled vibration response of the eccentric rotor in SRM can be analyzed and discussed rapidly; only the stator’s winding currents obtained by experiment or electromagnetic simulation is needed as input.

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Guo, Li-Xin, and Ee-Chon Teo. "Prediction of the Modal Characteristics of the Human Spine at Resonant Frequency Using Finite Element Models." Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine 219, no. 4 (April 1, 2005): 277–84. http://dx.doi.org/10.1243/095441105x34275.

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To understand the dynamic characteristics of the human spine, a detailed three-dimensional finite element model of the lower thorax to pelvis segment, T12-pelvis, was developed based on actual vertebral geometry. After modal analysis, the resonant frequencies of different spinal segments were obtained. The vibration mode of T12-pelvis shows that the human upper body mainly performs the vertical motion during whole-body vibration and the lumbar spine segment conducts translation and rotation in the sagittal plane. The lower segments of the lumbar spine move in flexion and the upper lumbar segments move in extension. This investigation may be helpful in understanding further the biomechanical behaviour of the human spine under the condition of whole-body vibration and to offer potential references for spinal disease treatments and product design in industry.

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Liu, Wei, Ying Cao Zhou, and Qing Zhao. "A New Analytical Model on Lateral Vibration and Impact of Drill String - Choice of Safe and Fast Drilling." Applied Mechanics and Materials 29-32 (August 2010): 2350–55. http://dx.doi.org/10.4028/www.scientific.net/amm.29-32.2350.

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The severe lateral vibration and impact of drill string will not only cause the damage of drill string but also have bad effects on the quality of directional drilling operation. It is difficult to control lateral vibration amplitude and impact intensity even with advanced measurement apparatus while drilling. So it is feasible to use a theoretic method to analyze and predict lateral vibration of drill string in order to adjust and optimize drilling parameters in real-time. On the basis of beam-column series and spring-concentrated mass model, a new analytical model is established to realize the control of lateral vibration and impact by controlling some key factors, such as under-gauge stabilizer, initial phase angle and initial deformation, WOB (weight on bit) and ROB (rotation of bit).

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Beck, Jordan P., Marc N. Muniz, Cassidy Crickmore, and Logan Sizemore. "Physical chemistry students’ navigation and use of models to predict and explain molecular vibration and rotation." Chemistry Education Research and Practice 21, no. 2 (2020): 597–607. http://dx.doi.org/10.1039/c9rp00285e.

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Models that are used to predict and explain phenomena related to molecular vibration and rotation are ubiquitous in physical chemistry, and are of importance in many related fields. Yet, little work has been done to characterize student use and application of these models. We describe the results of a multi-year, multi-institutional qualitative study to investigate how students work with and apply models of molecular vibration and rotation. Our findings indicate that a sizable fraction of students (1) struggle to interpret the meaning of wavefunctions, (2) do not appropriately build potential and kinetic energy terms into models, and (3) conflate portions of various model systems. The data suggests that the ordering of content in the quantum chemistry course impacts students’ ideas about the rotational and vibrational behavior of molecules. The results are analyzed through the lenses of a two theoretical frameworks: one for scientific modeling, and one for heuristics in the context of chemistry. Implications for research and teaching practice are provided.

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Ackerhalt, Jay R., and Peter W. Milonni. "Chaos and incoherence in a classical rotation-vibration model of infrared multiple-photon excitation." Physical Review A 37, no. 5 (March 1, 1988): 1552–62. http://dx.doi.org/10.1103/physreva.37.1552.

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Troltenler, D., J. A. Maruhn, W. Greiner, and S. G. Rohozinski. "An extended version of the rotation-vibration model with different proton and neutron deformations." Nuclear Physics A 494, no. 2 (April 1989): 235–43. http://dx.doi.org/10.1016/0375-9474(89)90021-3.

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Bastrukov, S., J. W. Yu, R. X. Xu, and I. Molodtsova. "Vibration-Powered Radiation of Quaking Magnetar." ISRN Astronomy and Astrophysics 2011 (January 5, 2011): 1–5. http://dx.doi.org/10.5402/2011/843825.

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In juxtaposition with the standard model of rotation-powered pulsar, the model of vibration-powered magnetar undergoing quake-induced torsional Alfvén vibrations in its own ultrastrong magnetic field experiencing decay is considered. The presented line of argument suggests that the gradual decrease of frequencies (lengthening of periods) of long-periodic-pulsed radiation detected from a set of X-ray sources can be attributed to magnetic-field-decay-induced energy conversion from seismic vibrations to magnetodipole radiation of quaking magnetar.

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Jiang, Bin, Pei Yi Zhao, Ji Guang Song, Bo Chen, and Jin Xuan Bai. "Vibration-Wear Characteristics of Cutter in High Speed Ball-End Milling Hardened Steel." Key Engineering Materials 522 (August 2012): 81–86. http://dx.doi.org/10.4028/www.scientific.net/kem.522.81.

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For vibration-wear characteristics of cutter in high speed ball-end milling hardened steel, established vibration-wear model of high speed milling cutter according to the principle of friction work, researched the influence of basic frequency and multiplication frequency of cutter vibration on its wear, and analyzed the interaction between cutter vibration and wear. By means of changing cutter extended length, rotation speed and cutting depth, made the change of cutter vibration, analyzed the influence of cutter vibration on its fretting and impact wear, explored the evolution process of composite vibration wear of cutter. Results show that the interaction between fretting fatigue wear and the impact wear make for cutter vibration-wear, lead to the increase of cutting force and vibration amplitude, and further increase the interaction strength of vibration and wear.

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Yan, Hongbo, Yu Niu, Hong Gao, and Hongbo Hao. "Research on Chaos Response of the Nonlinear Vibration System of Giant Magnetostrictive Actuator." Mathematical Problems in Engineering 2020 (March 19, 2020): 1–14. http://dx.doi.org/10.1155/2020/4281418.

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In the present study, the chaotic response of the nonlinear magnetostrictive actuator (GMA) vibration system is investigated. The mathematical model of the nonlinear GMA vibration system is established according to J-A hysteresis nonlinear model, quadratic domain rotation model, Newton’s third law, and principle of GMA structural dynamics by analyzing the working principle of GMA. Then, the Melnikov function method is applied to the threshold condition of the chaotic response of the system to obtain the sense of Smale horseshoe transformation. Furthermore, the mathematical model is solved to investigate the system response to the excitation force and frequency. Accordingly, the corresponding displacement waveform, phase plane trajectory, Poincaré map, and amplitude spectrum are obtained. The experimental simulation is verified using Adams software. The obtained results show that the vibration equation of the nonlinear GMA vibration system has nonlinear and complex motion characteristics with different motion patterns. It is found that the vibration characteristics of the system can be controlled through adjusting the excitation force and frequency.

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Journal articles on the topic 'ROTATION-VIBRATION MODEL'

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