scholarly journals Analysis of Nonlinear Dynamic Characteristics of a Mechanical-Electromagnetic Vibration System with Rubbing

2019 ◽  
Vol 9 (21) ◽  
pp. 4612
Author(s):  
Yiming Li ◽  
Zhilong Huang ◽  
He Li ◽  
Guiqiu Song
Keyword(s):  
Friction Coefficient ◽  
Dynamic Characteristics ◽  
Chaotic Motion ◽  
Nonlinear Dynamic ◽  
Response Amplitude ◽  
Jump Discontinuity ◽  
Excitation Current ◽  
Radial Stiffness ◽  
Chaotic Region ◽  
Coupling System

In this study, a rotor-bearing-runner system (RBRS) considering multiple nonlinear factors is established, and the complex nonlinear dynamic behavior of the coupling system is studied. The effects of excitation current, radial stiffness, and friction coefficient on dynamic characteristics are analyzed by numerical simulation. The research results show that the dynamic properties of the coupling system caused by different nonlinear factors are interactional. With the changes of different parameters, the RBRS presents multiple motion states, including periodic-n, quasi-periodic, and chaotic motion. The increase of the excitation current Ij has a certain inhibitory effect on the response amplitude of the system and makes the motion state of the system more complex, the chaotic motion wider, and the jump discontinuity enhanced. With the increase of radial stiffness kr, the motion complexity of the coupling system increases, the chaotic region increases, the response amplitude increases, and the vibration intensity increases. With the increase of the friction coefficient μ, the chaotic region increases first and decreases, the different motions alternate frequently, and the response amplitude gradually increases. This study can not only help to understand the dynamic characteristics of RBRS, but also help the stable operation of the generator set.

scholarly journals Nonlinear dynamic characteristics of planetary gear transmission system considering squeeze oil film

2020 ◽  
pp. 146134842093566
Author(s):  
Jingyue Wang ◽  
Ning Liu ◽  
Haotian Wang ◽  
Lixin Guo
Keyword(s):  
Dynamic Characteristics ◽  
Chaotic Motion ◽  
Nonlinear Dynamic ◽  
Excitation Frequency ◽  
Planetary Gear ◽  
High Excitation ◽  
Gear Transmission System ◽  
Nonlinear Dynamic Characteristics ◽  
Period Motion ◽  
Lubricant Viscosity

Based on the planetary gear transmission system considering the coupling effects of friction and elastohydrodynamic lubrication, a torsional dynamic model considering friction, oil film, time-varying meshing stiffness, meshing damping, and gear backlash is established. The Runge–Kutta numerical method is used to solve the vibration equation of the system. The bifurcation diagram and largest Lyapunov exponent are used to analyze the dynamic characteristics of the system under different bifurcation parameters such as the excitation frequency, lubricant viscosity, sun–planet backlash, and planet–ring backlash. The numerical results demonstrate that with the increase of excitation frequency, the system exhibits rich nonlinear dynamic characteristics such as short-period motion, long-period motion, and chaotic motion. With the increase of lubricant viscosity, the chaotic motion of the system is suppressed at low excitation frequency and the periodic motion of the system increases at high excitation frequency. With the increase of sun–planet backlash, the chaotic motion of the system increases at low excitation frequency, and the bifurcation characteristics become complicated at high excitation frequency and enters chaotic motion in advance. With the increase of ring–planet backlash, the system delays into chaotic motion at low excitation frequency and bifurcates from single-period motion to multi-period motion in advance at high excitation frequency.

scholarly journals Non-Linear Dynamic Analysis of Drill String System with Fluid-Structure Interaction

2021 ◽  
Vol 11 (19) ◽  
pp. 9047
Author(s):  
Rongpeng Wang ◽  
Xiaoqin Liu ◽  
Guiqiu Song ◽  
Shihua Zhou
Keyword(s):  
Dynamic Characteristics ◽  
Chaotic Motion ◽  
Period Doubling ◽  
Drill String ◽  
Jump Discontinuity ◽  
Drilling Process ◽  
Prevention Measures ◽  
Fluid Structure ◽  
Non Linear ◽  
Effect Of Support

In this research, the non-linear dynamics of the drill string system model, considering the influence of fluid—structure coupling and the effect of support stiffness, are investigated. Using Galerkin’s method, the equation of motion is discretized into a second-order differential equation. On the basis of an improved mathematical model, numerical simulation is carried out using the Runge—Kutta integration method. The effects of parameters, such as forcing frequency, perturbation amplitude, mass ratio and flow velocity, on the dynamic characteristics of the drill string system are studied under different support stiffness coefficients, in which bifurcation diagrams, waveforms, phase diagrams and Poincaré maps of the system are provided. The results indicate that there are various dynamic model behaviors for different parameter excitations, such as periodic, quasi-periodic, chaotic motion and jump discontinuity. The system changes from chaotic motion to periodic motion through inverse period-doubling bifurcation, and the support stiffness has a significant influence on the dynamic response of the drill string system. Through in-depth study of this problem, the dynamic characteristics of the drill string can be better understood theoretically, so as to provide a necessary theoretical reference for prevention measures and a reduction in the number of drilling accidents, while facilitating the optimization of the drilling process, and provide basis for understanding the rich and complex nonlinear dynamic characteristics of the deep-hole drill string system. The study can provide further understanding of the vibration characteristics of the drill string system.

scholarly journals Modeling and Parameter Optimization of Dynamic Characteristic Variables of Ballast Bed during Operation for Dynamic Track Stabilizer

Complexity ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Bo Yan ◽  
Jingjing Yang
Keyword(s):  
Dynamic Characteristics ◽  
Simulation Analysis ◽  
Traffic Density ◽  
Operating Parameters ◽  
Simulation Accuracy ◽  
Railway Line ◽  
Coupling System ◽  
Track System ◽  
Parameterized Model ◽  
Railway Maintenance

The high traffic density of railway line causes ballasted track to be extremely busy, and thus it is particularly important to improve the efficiency during railway maintenance. The changing law of dynamic characteristics of ballast bed during operation for the dynamic track stabilizer is conducive to optimize simulation analysis of the vehicle-track system, so as to provide an optimized choice of operating parameters for promoting the pertinence and efficiency of dynamic track stabilizer. This paper presents the acceleration response of vehicle-track-subgrade system during operation of a WD-320 dynamic track stabilizer and proposes the range of effective operating parameters. Then, the influence of operating parameters on the dynamic characteristics of the ballast bed is discussed for searching the optimal operating parameters under the single factor influence. Finally, the change laws including the support stiffness, damping, lateral resistance, and subsidence for the ballast bed are studied, and a parameterized model for dynamic characteristics of the ballast bed which can optimize the selection for operating parameters is constructed, rendering an effective reference variable for improving the simulation accuracy of the vehicle-track coupling system.

scholarly journals Dynamic characteristics of the gear-rotor system in compressed air energy storage considering friction effects

2021 ◽  
Vol 12 (1) ◽  
pp. 677-688
Author(s):  
Xinran Wang ◽  
Wen Li ◽  
Dongxu Hu ◽  
Xingjian Dai ◽  
Haisheng Chen
Keyword(s):  
Energy Storage ◽  
Friction Coefficient ◽  
Dynamic Characteristics ◽  
Surface Friction ◽  
Rotor System ◽  
Compressed Air ◽  
Contact Temperature ◽  
Tooth Surface ◽  
Compressed Air Energy Storage ◽  
Rotating Speed

Abstract. The tooth surface friction effects and the resulting tooth surface contact temperature are important factors for the dynamic characteristics of a gear-rotor system in compressed air energy storage (CAES). Therefore, a 3∘ of freedom finite-element model of the system is set up in which the lubrication state of the gear pair, tooth surface friction, contact temperature of the tooth surface, backlash and unbalanced excitation are considered. The friction coefficient is calculated according to the variation of the lubrication state, and the tooth surface contact temperature is derived based on the friction coefficient. The tooth profile deformation caused by the change in the contact temperature is calculated, and the resulting effects on backlash and comprehensive meshing stiffness are considered. The influence of rotating speed, torque load and viscosity of lubricating oil on the system response is studied, and the variation of the friction coefficient, flash temperature of the tooth surface, pressure of the tooth surface and so on are discussed in detail. The results indicate that when the friction coefficient is derived according to the variation of the lubrication state, the variation of the contact temperature of the tooth surface with rotating speed is quite different from that calculated based on a friction coefficient which is set artificially. This leads to a new variation of the dynamic response of the gear-rotor system, and the method of stabilizing the operation of the system is put forward based on the optimization curve for the operation of the system. The results obtained in this paper will provide a reference for the study and design of a gear-rotor system in CAES.

scholarly journals Nonlinear Dynamics of the Rigid Drum for Vibratory Roller on Elastic Subgrades

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Lun Liu ◽  
Fenghui Wang ◽  
Shupeng Sun ◽  
Weiming Feng ◽  
Chao Guo
Keyword(s):  
Nonlinear Dynamics ◽  
Phase Diagram ◽  
Dynamic Characteristics ◽  
Nonlinear Dynamic ◽  
Period Doubling ◽  
Time History ◽  
Nonlinear Dynamic Model ◽  
Compaction Process ◽  
Adjustment Strategy ◽  
Vibratory Compaction

In this paper, a coupling nonlinear dynamic model of the drum and subgrade is established for the vibratory roller. The dynamic characteristics of the rigid drum of the vibratory roller in the process of vibratory compaction are comprehensively investigated by time history, phase diagram, frequency spectrum, Poincare map, and bifurcation diagram. During the compaction process, the stiffness of the subgrade increases and the motion of the rigid drum of the vibratory roller changes from a single period to multiple periods and finally enters chaos by the way of period doubling. Moreover, the roller parameters also significantly affect the dynamic characteristics of the rigid drum and the compaction effect of the subgrade. Based on detailed numerical results, a parameter adjustment strategy about the roller frequency and nominal amplitude is proposed, which can avoid the “bouncing” of the drum during compaction and improve the compaction efficiency.

Effect of Secondary Force on Rigidity of Oil Film of the Slipper Pair Based on Hydrostatic Support

2012 ◽  
Vol 468-471 ◽  
pp. 1380-1383
Author(s):  
Hui Wang ◽  
Yu Xin Wang
Keyword(s):  
Computer Simulation ◽  
Friction Coefficient ◽  
Simulation Model ◽  
Dynamic Characteristics ◽  
Mathematics Model ◽  
Support Structure ◽  
Oil Film ◽  
Work Pressure ◽  
The Impact

Rigidity of oil film is an important hydrostatic support performance of the slipper pair. This paper establishes the mathematics model of hydrostatic support structure on the basis of considering secondary force. And establish the simulation model of rigidity of oil film by using the toolbox of Simulink. Study the dynamic characteristics of rigidity of oil film under the influence of secondary force through computer simulation. And reach a conclusion that the impact of secondary force on rigidity of oil film has a relationship with friction coefficient and work pressure.

Sign in / Sign up

Export Citation Format

Share Document