scholarly journals Study on the Different Effects of Power and Trailer Wheelsets on Wheel Polygonal Wear

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
X. N. Zhao ◽  
G. X. Chen ◽  
Z. Y. Huang ◽  
C. G. Xia
Keyword(s):  
Vibration Frequency ◽  
Complex Eigenvalue ◽  
Brake Pad ◽  
High Speeds ◽  
Eigenvalue Method ◽  
Excited Vibration ◽  
Creep Force ◽  
Polygonal Wear ◽  
Unstable Vibration ◽  
Development Tendency

The wheels of power and trailer wheelset show different polygonal characteristics since their structures are obviously different. Therefore, the frictional self-excited vibration models of wheelset-track systems are established based on the viewpoint of the frictional self-excited vibration in reducing the wheel polygonal wear. Then, the motion stability of wheelset-track systems is studied by using the complex eigenvalue method. The results show that when the creep force between the wheel and rail is saturated, the unstable vibration frequency of the power wheelset is prone to induce 19-20th-order polygonal wear of the wheel, and the trailer wheelset is prone to induce 20-21th-order polygonal wear of the wheel. Meanwhile, the wheel polygonal wear can be effectively alleviated through changing the gearbox position of the power wheelset. And avoiding disc braking at high speeds can suppress the occurrence of wheel polygonal wear. In addition, the development tendency of wheel polygonal wear can be reduced by increasing the Young’s modulus of the brake pad, but Poisson’s ratio has little effect on the development tendency.

Friction-Induced, Self-Excited Vibration of a Pantograph-Catenary System

2013 ◽  
Vol 135 (5) ◽  
Author(s):  
W. J. Qian ◽  
G. X. Chen ◽  
W. H. Zhang ◽  
H. Ouyang ◽  
Z. R. Zhou
Keyword(s):  
Friction Coefficient ◽  
Lift Force ◽  
Spatial Location ◽  
The Self ◽  
Complex Eigenvalue ◽  
Suspension Spring ◽  
Eigenvalue Method ◽  
Excited Vibration ◽  
The Coefficient Of Friction ◽  
Catenary System

A dynamic model of a pantograph-catenary system is established. In the model, motion of the pantograph is coupled with that of the catenary by friction. Stability of the pantograph-catenary system is studied using the finite element complex eigenvalue method. Numerical results show that there is a strong propensity of self-excited vibration of the pantograph-catenary system when the friction coefficient is greater than 0.1. The dynamic transient analysis results show that the self-excited vibration of the pantograph-catenary system can affect the contact condition between the pantograph and catenary. If the amplitude of the self-excited vibration is strong enough, the contact may even get lost. Parameter sensitivity analysis shows that the coefficient of friction, static lift force, pan-head suspension spring stiffness, tension of contact wire, and the spatial location of pantograph have important influences on the friction-induced, self-excited vibration of the pantograph-catenary system. Bringing the friction coefficient below a certain level and choosing a suitable static lift force can suppress or eliminate the contact loss between the pantograph and catenary.

Effect of the unstable vibration of the disc brake system of high-speed trains on wheel polygonalization

2019 ◽  
Vol 234 (1) ◽  
pp. 80-95 ◽  
Author(s):  
BW Wu ◽  
QF Qiao ◽  
GX Chen ◽  
JZ Lv ◽  
Q Zhu ◽  
...  
Keyword(s):  
Finite Element ◽  
Formation Mechanism ◽  
High Speed ◽  
Influence Factors ◽  
The Self ◽  
Disc Brake ◽  
Excited Vibration ◽  
High Speed Trains ◽  
Creep Force ◽  
Polygonal Wear

This paper conducts a detailed investigation into the formation mechanism of wheel polygonalization in high-speed trains and its influence factors through numerical simulation. A finite element model including two rails, one wheelset, and three disc brake units is set up to study the formation mechanism of wheel polygonalization in high-speed trains based on the point of view of frictional self-excited vibration. Using the finite element complex analysis, the dynamic stability of the wheelset–track–disc brake system is studied. In addition, the influence factors on the wheel polygonalization are investigated. Results show that when the longitudinal creep force is unsaturated, the 21-order polygonal wear of wheels occurs easily due to the self-excited vibration of the disc brake unit. When the longitudinal creep force is saturated, the 12-order polygonal wear of wheels probably occurs due to the self-excited vibration of the disc brake unit. The bigger the friction coefficient between the brake disc and pad, the greater the occurrence propensity of the polygonal wear of wheels. Vertical fastener damping that is too large or too small is disadvantageous for suppressing wheel corrugation. However, increasing the lateral fastener damping is beneficial for reducing the polygonal wear of wheels. When the vertical fastener stiffness is 25 MN/m, 7-order, 9-order, and 14-order wheel polygonalization can easily occur. A higher lateral fastener stiffness is beneficial for the suppression of wheel polygonalization.

scholarly journals Analysis of influence factors of rail corrugation in small radius curve track

2021 ◽  
Vol 12 (1) ◽  
pp. 31-40
Author(s):  
Zhiqiang Wang ◽  
Zhenyu Lei
Keyword(s):  
Influence Factors ◽  
Small Radius ◽  
Track Structure ◽  
Complex Eigenvalue ◽  
Three Dimensional Model ◽  
Rail Corrugation ◽  
Finite Element Software ◽  
Rail System ◽  
Side Rail ◽  
Excited Vibration

Abstract. In order to effectively prevent and control the generation and development of rail corrugation, according to the actual line condition of the small radius curve section, the vehicle (with flexible wheel sets)–track space coupled model was established by using the multi-body dynamic software UM (Universal Mechanism), which could consider the coupled relationship in three directions of space, and the dynamic analysis for the corrugation section was carried out by using the model. Then, based on the theory of friction self-excited vibration, the three-dimensional model of a wheel–rail system was established by using the finite-element software ABAQUS, and the complex eigenvalue analysis of influence factors of rail corrugation was conducted based on wheel–rail contact parameters obtained by dynamic calculation. Through the stability analysis of the wheel–rail system with different fastener vertical and lateral stiffnesses, friction coefficients, and superelevation states, we find that properly increasing the fastener vertical and lateral stiffnesses, controlling the wheel–rail friction coefficient below 0.4, and keeping the balanced superelevation state of the track structure can effectively reduce the occurrence possibility of unstable vibration of the wheel–rail system, thus inhibiting the generation and development of rail corrugation. The excess superelevation state of the track structure results in the unstable friction self-excited vibration of the wheel–rail system at the inner wheel–inner rail, while the deficient superelevation state results in the unstable friction self-excited vibration of the wheel–rail system at the outer wheel–outer rail, which shows that the superelevation state of the track structure directly affects the formation of rail corrugation and determines the development order of corrugation of inner and outer rails. This conclusion can well explain the cause of corrugation appearing on only one side rail.

Dynamics of a Cleaning Blade Based on a 2DOF Link Model

2009 ◽  
Author(s):  
Yoshinori Inagaki ◽  
Tsuyoshi Nohara ◽  
Go Kono ◽  
Minoru Kasama ◽  
Masatsugu Yoshizawa
Keyword(s):  
Amplitude Equation ◽  
Laser Printer ◽  
Small Disturbance ◽  
Governing Equations ◽  
Supercritical Bifurcation ◽  
Narrow Region ◽  
Hamiltonian Hopf Bifurcation ◽  
Excited Vibration ◽  
Link Model ◽  
Unstable Vibration

To analyze the dynamics of a cleaning blade in a laser printer, observation of the vibration of the cleaning blade and analysis of a 2DOF model have been carried out. First, from the observation of the vibration of the actual cleaning blade, the stationary self-excited vibration has been confirmed. Next, a 2DOF model has been presented and its governing equations have been derived. The bottom of the model is assumed to always contact a floor surface, and the friction coefficient is constant and not dependent on the floor velocity. Third, by solving the equations governing the motion of the 2DOF model, five patterns of static equilibrium states have been obtained. Moreover it has been clarified from linear stability analysis that one of five patterns corresponds to the shape of the cleaning blade and is unstable for a small disturbance in a narrow region. This unstable vibration is a bifurcation classified as Hamiltonian-Hopf bifurcation. Fourth, by keeping up to the 3rd order terms, the nonlinear complex amplitude equation has been obtained, and the steady amplitude can be decided. As a result, the steady amplitude has been determined as the products of the 2nd order terms. Furthermore it has been clarified that such a self-excited vibration is classified as the supercritical bifurcation.

Modeling and Analysis of a Manipulator Joint Driven Through a Worm Gear Transmission

1989 ◽  
Author(s):  
B. W. Mooring ◽  
D. C. May ◽  
M. S. Schulte
Keyword(s):  
Linear Model ◽  
Nonlinear Model ◽  
High Velocity ◽  
Experimental System ◽  
Worm Gear ◽  
Gear Transmission ◽  
Servo Motor ◽  
Modeling And Analysis ◽  
Excited Vibration ◽  
Unstable Vibration

Abstract Worm gear transmissions are capable of high velocity ratios as well as redirection of rotation. Both of these features are desirable for some robot geometries. A problem has been encountered in several robot designs, however, where a self excited vibration occurs for some configurations of the manipulator in the joint containing the worm gear. In this work, a system which exhibits this type of undesirable motion is examined. The system consists of a DC servo motor which is used to position a flexible cantilever arm through a worm gear transmission. A nonlinear model is developed to describe the motion of the system. The model is then validated by comparing the predicted response to the observed response of an experimental system. It is demonstrated that the model accurately predicts the onset of the unstable vibration. The model is then linearized and it is shown that the linear model will predict the occurrence of the instability as well.

scholarly journals Parameter Identification of Brake Pad Shims for Complex Eigenvalue Analysis

PAMM ◽  
2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Dominik Schmid ◽  
Vincent Sessner ◽  
Nils Gräbner ◽  
Utz von Wagner ◽  
Kay André Weidenmann
Keyword(s):  
Parameter Identification ◽  
Eigenvalue Analysis ◽  
Complex Eigenvalue ◽  
Brake Pad ◽  
Complex Eigenvalue Analysis

Analysis of the Frictional Vibration of a Cleaning Blade in Laser Printers Based on a Two-Degree-Of-Freedom Model

2011 ◽  
Vol 7 (1) ◽  
Author(s):  
Go Kono ◽  
Yoshinori Inagaki ◽  
Hiroshi Yabuno ◽  
Tsuyoshi Nohara ◽  
Minoru Kasama
Keyword(s):  
Frictional Coefficient ◽  
The Self ◽  
Laser Printer ◽  
Hamiltonian Hopf Bifurcation ◽  
Excited Vibration ◽  
Negative Damping ◽  
Link Model ◽  
Unstable Vibration ◽  
Two Degree Of Freedom ◽  
Frictional Vibration

This research aims to analyze the dynamics of the self-excited vibration of a cleaning blade in a laser printer. First, it is experimentally indicated that that the self-excited vibration is not caused by the negative damping effect based on friction. Next, the excitation mechanism and dynamics of the vibration are theoretically clarified using an essential 2DOF link model, with emphasis placed on the contact between the blade and the photoreceptor. By solving the equations governing the motion of the analytical model, five patterns of static equilibrium states are obtained, and the effect of friction on the static states is discussed. It is shown that one of five patterns corresponds to the shape of the practical cleaning blade, and it is clarified through linear stability analysis that this state becomes dynamically unstable, due to both effects of friction and mode coupling. Furthermore, the amplitude of the vibration in the unstable region is determined through nonlinear analysis. The obtained results show that this unstable vibration is a bifurcation classified as a supercritical Hamiltonian-Hopf bifurcation, and confirms the occurrence of mode-coupled self-excited vibration on a cleaning blade when a constant frictional coefficient is assumed.

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