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.

scholarly journals Transient CFD Simulation on Dynamic Characteristics of Annular Seal under Large Eccentricities and Disturbances

Energies ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 4056
Author(s):  
Kai Zhang ◽  
Xinkuo Jiang ◽  
Shiyang Li ◽  
Bin Huang ◽  
Shuai Yang ◽  
...  
Keyword(s):  
Dynamic Model ◽  
Dynamic Characteristics ◽  
Nonlinear Dynamic ◽  
Cfd Simulation ◽  
Resonance Region ◽  
Nonlinear Dynamic Model ◽  
Annular Seal ◽  
Transient Simulations ◽  
Computational Fluid Dynamics Cfd ◽  
Annular Seals

Annular seals of turbomachinery usually suffer from various degrees of eccentricities and disturbances due to the rotor–stator misalignment and radial loads, while the discussion of annular seal under both large static eccentricities and dynamic disturbances is relatively limited. In this paper, the applicability of linear assumption and reliability of nonlinear dynamic model for eccentric annular seals under large eccentricities and disturbances is discussed based on the investigation of seals with various rotor motions through computational fluid dynamics (CFD). After the validation of transient CFD methods by comparison with experimental and bulk theory results, the dynamic behaviors of annular seal are analyzed by adopting both direct transient simulations and the nonlinear Muszynska model. The results show that the nonlinear dynamic model based on rotor circular whirls around seal center can predict the fluid excitations of different types of rotor motions well under small static eccentricities, while it is limited severely with large static eccentricities, which indicates that the dynamic characteristics of annular seal under large eccentricities are related with the rotor’s motion ways. The paper provides a reference for studies of rotor–seal system with complex rotor motions considering radial loads or running across the resonance region.

Dynamic Simulation of Large Flow Solenoid Valve

2016 ◽  
Author(s):  
Z. Liu ◽  
X. Han ◽  
Y. F. Liu
Keyword(s):  
Dynamic Model ◽  
Dynamic Simulation ◽  
Dynamic Characteristics ◽  
Nonlinear Dynamic ◽  
Structural Parameters ◽  
Solenoid Valve ◽  
Simulation Software ◽  
Experimental Results ◽  
Nonlinear Dynamic Model ◽  
Large Flow

A nonlinear dynamic model of a large flow solenoid is presented with the multi-physics dynamic simulation software called SimulationX. Validation is performed by comparing the experimental results with the simulated ones. The dynamic characteristics of the large flow solenoid valve are analyzed. Different structural parameters are modified in this research and the diameter of the orifice is proved to be one of the most important parameters which influences the pressure response most.

Bifurcation and Chaos of a Spur Gear Transmission System With Non-Uniform Wear

2020 ◽  
Vol 143 (3) ◽  
Author(s):  
Zhibo Geng ◽  
Ke Xiao ◽  
Junyang Li ◽  
Jiaxu Wang
Keyword(s):  
Dynamic Model ◽  
Dynamic Characteristics ◽  
Nonlinear Dynamic ◽  
Operating Time ◽  
Spur Gear ◽  
Gear Transmission ◽  
Nonlinear Dynamic Model ◽  
Gear Backlash ◽  
Gear Transmission System ◽  
Nonlinear Dynamic Characteristics

Abstract In this study, a nonlinear dynamic model of a spur gear transmission system with non-uniform wear is proposed to analyze the interaction between surface wear and nonlinear dynamic characteristics. A quasi-static non-uniform wear model is presented, with consideration of the effects of operating time on mesh stiffness and gear backlash. Furthermore, a nonlinear dynamic model with six degrees-of-freedom is established considering surface friction, time-varying gear backlash, time-varying mesh stiffness, and eccentricity, and the Runge–Kutta method applied to solve this model. The bifurcation and chaos in the proposed dynamic model with the change of the operating time and the excitation frequency are investigated by bifurcation and spectrum waterfall diagrams to analyze the bifurcation characteristics and the dimensionless mesh force. It is found that surface wear is generated with a change in operating time and affects the nonlinear dynamic characteristics of the spur gear system. This study provides a better understanding of nonlinear dynamic characteristics of gear transmission systems operating under actual conditions.

The Gap Nonlinear Characteristics of Gear Transmission System under External Excitation

2012 ◽  
Vol 215-216 ◽  
pp. 1067-1070
Author(s):  
Kang Huang ◽  
Jue Li ◽  
Xin Jin ◽  
Qi Chen
Keyword(s):  
Dynamic Characteristics ◽  
Nonlinear Dynamic ◽  
Degrees Of Freedom ◽  
Transmission System ◽  
Gear Transmission ◽  
Engineering Practice ◽  
Nonlinear Dynamic Model ◽  
Gear Transmission System ◽  
Nonlinear Dynamic Characteristics ◽  
Domain Of Parameters

For the study of nonlinear dynamic characteristics of a pair of gears in an external torque under gear meshing error excitation, we will establish two degrees of freedom nonlinear torsional vibration model. The use of Matlab / Simulink for numerical simulation solves the nonlinear dynamic model of the gear gap. Study the dynamic characteristics of the system in a certain domain of parameters on external incentive conditions, as well as external motivation of gear transmission system dynamic characteristics influence. The results have important practical value for future engineering practice on gear transmission system's dynamic design, and have important theoretical significance for complex gear transmission system dynamics study.

scholarly journals Dynamic characteristics of mean type dimension lathe installed on rubber-metal anti-vibration supports

2017 ◽  
Vol 2 (5) ◽  
pp. 26-30
Author(s):  
А. Денисенко ◽  
A. Denisenko
Keyword(s):  
Dynamic Model ◽  
Elastic Deformation ◽  
Dynamic Characteristics ◽  
Nonlinear Dynamic ◽  
Vibration Isolation ◽  
Elastic Characteristic ◽  
Frequency Characteristics ◽  
Experimental Dependence ◽  
Proof System ◽  
Nonlinear Dynamic Model

On the basis of a nonlinear dynamic model of a vibration-proof system at power excitation there are formed amplitude-frequency characteristics of a lathe installed on rubber-metal anti-vibration supports, and an area of efficient vibration isolation is defined. An elastic characteristic of the model is presented as an approximating dependence obtained on the basis of the experimental dependence of support elastic deformation changes upon loading.

Nonlinear Dynamics of Mechanical Systems with Sectional Frictions

2007 ◽  
Vol 353-358 ◽  
pp. 754-757 ◽  
Author(s):  
Bang Chun Wen ◽  
Zhao Hui Ren ◽  
Qing Kai Han ◽  
Xiao Peng Li ◽  
Ju Quan Mao
Keyword(s):  
Nonlinear Dynamics ◽  
Mechanical System ◽  
Dynamic Characteristics ◽  
Nonlinear Theory ◽  
Asymptotic Method ◽  
Nonlinear Dynamic ◽  
Mechanical Systems ◽  
Friction Coefficients ◽  
Damping Coefficients ◽  
Nonlinear Dynamic Characteristics

This paper presents mainly the nonlinear dynamics of the mechanical system with sectional frictions and combination friction coefficients. It is clear that the nonlinear dynamic characteristics of mechanical systems with sectional frictions are quite different from those of classical machinery, and have more precise and valuable in many practical projects. The expressions of various nonlinear forces are given firstly and the approximation solutions of the system are found with asymptotic method in nonlinear theory, and the combination friction coefficients and damping coefficients of the materials are obtained. Then some nonlinear dynamic characteristics of the system with sectional frictions are also discussed. The results are very important for designers of these machines.

Study on Characteristics of Vibration Friction for Pile-Soil System

2007 ◽  
Vol 353-358 ◽  
pp. 762-765 ◽  
Author(s):  
Xiao Peng Li ◽  
He Li ◽  
Qing Kai Han ◽  
Jie Liu ◽  
Bang Chun Wen
Keyword(s):  
Nonlinear Dynamics ◽  
Dynamic Model ◽  
Dynamic Characteristics ◽  
Nonlinear Dynamic ◽  
Pile Driving ◽  
Working Process ◽  
Soil System ◽  
Friction Theory ◽  
Pile Driver ◽  
Simulation Results

Vibratory pile driver-extractor is broadly applied in civil constructions, but the friction vibration theory and dynamic characteristics of friction vibration are not studied well. In this paper, the vibration friction characteristics and dynamics of pile driving process are studied based on nonlinear dynamics and friction theory. A dynamic model of system is established firstly, and then nonlinear dynamic principle and working process are studied in details. The simulation results can provide useful guidance for both vibration friction research in engineering and design in the development of such machines.

scholarly journals Nonlinear Dynamics and Analysis of a Planar Multilink Complex Mechanism with Clearance

2018 ◽  
Vol 2018 ◽  
pp. 1-17 ◽  
Author(s):  
Xiulong Chen ◽  
Shuai Jiang ◽  
Yu Deng ◽  
Qing Wang
Keyword(s):  
Nonlinear Dynamics ◽  
Dynamic Response ◽  
Phase Diagrams ◽  
Dynamic Model ◽  
Dynamic Behavior ◽  
Nonlinear Dynamic ◽  
Lagrange Equation ◽  
Nonlinear Dynamic Model ◽  
Planar Mechanism ◽  
Driving Speed

In order to understand the nonlinear dynamic behavior of a planar mechanism with clearance, the nonlinear dynamic model of the 2-DOF nine-bar mechanism with a revolute clearance is proposed; the dynamic response, phase diagrams, Poincaré portraits, and largest Lyapunov exponents (LLEs) of mechanism are investigated. The nonlinear dynamic model of 2-DOF nine-bar mechanism containing a revolute clearance is established by using the Lagrange equation. Dynamic response of the slider’s kinematics characteristic, contact force, driving torque, shaft center trajectory, and the penetration depth for 2-DOF nine-bar mechanism are all analyzed. Chaos phenomenon existed in the mechanism has been identified by using the phase diagrams, the Poincaré portraits, and LLEs. The effects of the different clearance sizes, different friction coefficients, and different driving speeds on dynamic behavior are studied. Bifurcation diagrams with changing clearance value, friction coefficient, and driving speed are drawn. The research could provide important technical support and theoretical basis for the further study of the nonlinear dynamics of planar mechanism.

Nonlinear dynamic characteristics analysis and chaos control of a gear transmission system in a shearer under temperature effects

2019 ◽  
Vol 233 (16) ◽  
pp. 5691-5709 ◽  
Author(s):  
Jiajun Chen ◽  
Wei Li ◽  
Gaifang Xin ◽  
Lianchao Sheng ◽  
Song Jiang ◽  
...  
Keyword(s):  
Bifurcation Diagram ◽  
Dynamic Characteristics ◽  
Nonlinear Dynamic ◽  
Coupling Effect ◽  
Transmission System ◽  
Resonance Excitation ◽  
Gear Pair ◽  
Direct Drive ◽  
Nonlinear Dynamic Model ◽  
Dimensionless Analysis

Due to changes in the working temperature in a shearer transmission system, it is easy to cause the transmission gear to work abnormally. In this paper, the first gear pair in a cutting transmission system of a permanent magnet semi-direct drive shearer was taken as the research object. The coupling effect of time-varying meshing stiffness, meshing damping, bearing clearance and gear backlash under thermal deformation were fully considered. Then, a three degree of freedom nonlinear dynamic model of the gear pair was established, and a dimensionless analysis was performed. Finally, the Runge-Kutta method was used in the numerical calculations. The motion characteristics of the system were analysed through the gear’s bifurcation diagram of the temperature at different frequencies and the bifurcation diagram of the frequency at different temperatures. The meshing state was analysed at different frequencies and temperatures. For the chaotic motion generated in the system, a periodic resonance excitation was applied to control unstable motion. This study has revealed various specific effects of the temperature on the dynamic characteristics of the system. In addition, the periodic excitation method can effectively control the nonlinear motion in the system and realise the control of the chaos under the temperature effect.

scholarly journals Nonlinear Torsional Dynamics of Star Gearing Transmission System of GTF Gearbox

2020 ◽  
Vol 2020 ◽  
pp. 1-15 ◽  
Author(s):  
Siyu Wang ◽  
Rupeng Zhu
Keyword(s):  
Nonlinear Dynamic ◽  
Damping Ratio ◽  
Global Bifurcation ◽  
Period Doubling ◽  
Transmission System ◽  
Dynamic Responses ◽  
Nonlinear Dynamic Model ◽  
Chaotic Motions ◽  
Meshing Stiffness ◽  
And Control

Considering time-varying meshing stiffness, comprehensive errors, and piecewise backlash nonlinearities of gear and spline, a torsional nonlinear dynamic model of star gear-rotor coupling transmission system of (Geared Turbofan Engine) GTF aeroengine is established. By using the Runge–Kutta numerical integration method, the dynamic responses are solved, analyzed, and illustrated with the bifurcation parameters including input rotational speed, gear backlash, damping ratio, and comprehensive meshing errors. The motions of the star gearing system and diverse nonlinear dynamic characteristics are identified through global bifurcation, FFT spectra, Poincaré map, and the phase diagram. The results reveal that the star gear-rotor system exhibits abundant torsional nonlinear behaviors, including multiperiodic, quasi-periodic, and chaotic motions. Furthermore, the roads to chaos via quasi-periodicity, period-doubling scenario, and mutation are demonstrated. These results provide an understanding of undesirable torsional dynamic motion for the GTF transmission system and provide a reference for the design and control of gear system.

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