Clarifications on the Damping Mechanism Related to the Hunting Motion of the Wheel Axle of a Railway Vehicle

2017 ◽  
Vol 2017 (0) ◽  
pp. 215
Author(s):  
Barenten SUCIU
Keyword(s):  
Railway Vehicle ◽  
Hunting Motion

scholarly journals Computation of the Negative Damping Associated to the Hunting Motion of the Railway Wheelset, without Using Geometrical or Tribological Restrictions into the Model

2020 ◽  
Vol 5 (2) ◽  
pp. 210-217
Author(s):  
Barenten Suciu
Keyword(s):  
Characteristic Equation ◽  
Opposite Sign ◽  
Damping Ratio ◽  
Complex Conjugate ◽  
Railway Vehicle ◽  
Real Roots ◽  
Vibration Model ◽  
Hunting Motion ◽  
Negative Damping ◽  
Analytical Expressions

Recently, analytical expressions for the damped natural frequency and damping ratio were proposed for the so-called dynamical hunting, either by assuming that the wheel conicity can be neglected, or by imposing restrictions on the ratio between the lateral and longitudinal creep coefficients, and also, on the ratio of the track span to the yawing diameter. However, instead of a pair of complex conjugate roots, and two real roots, of opposite sign, two pairs of complex conjugate roots were obtained for the characteristic equation. Purpose of this work is to achieve accurate expressions for the damping associated to the hunting motion, without imposing geometrical or tribological limitations into the vibration model, and to evaluate the error on the damping ratio, introduced by the simplified models. Also, nature of the roots of the characteristic equation is discussed, relative to the critical speed of the railway vehicle.

The Hunting Behavior of Conventional Railway Trucks

1972 ◽  
Vol 94 (2) ◽  
pp. 752-761 ◽  
Author(s):  
N. K. Cooperrider
Keyword(s):  
Equations Of Motion ◽  
Linear Equations ◽  
Nonlinear Effects ◽  
Complex Model ◽  
Railway Vehicle ◽  
Hunting Behavior ◽  
Wheel Slip ◽  
Wheel Load ◽  
Hunting Motion ◽  
Nonlinear Equations Of Motion

Railway vehicles under certain conditions experience sustained lateral oscillations during which the wheel flanges bang from one rail to the other. It has been found that this behavior, called hunting, only occurs above certain critical forward velocities. Approximations to these critical velocities have been found from a stability analysis of the linear equations of motion for many different railway vehicle models. Hunting is characterized by violent motions that impose large loads on the vehicle and track, and bring several important nonlinear effects into play. This paper reports results of an analysis of nonlinear equations of motion written for two models of a railway truck. The influence of the nonlinear effects on stability is determined and the character of the hunting motion is investigated. One model represents a truck whose axle bearings are rigidly held in the truck frame while the truck frame is connected through a suspension system to a reference that moves along the track with constant velocity. The more complex model includes additional suspension elements between the axle bearings and truck frame. The effects of flange contact, wheel slip and Coulomb friction are described by nonlinear expressions. These results show the significant influence of flange contact on stability, and illustrate the effects of vehicle and track parameters such as rail adhesion, forward velocity, and wheel load on the forces and power dissipation at the wheel-rail interface.

Paper 8: Some Observations on Linear Theory of Railway Vehicle Instability

1965 ◽  
Vol 180 (6) ◽  
pp. 15-21
Author(s):  
R. E. D. Bishop
Keyword(s):  
Linear Theory ◽  
Limit Cycle ◽  
Railway Vehicle ◽  
Rapid Progress ◽  
General Terms ◽  
Hunting Motion ◽  
Made In

During ‘bogie hunting’, motion takes place in a limit cycle, so that a description of the motion in terms of linear theory cannot be found. It does not follow, however, that linear theory is valueless. On the contrary, rapid progress is now being made towards an understanding of the phenomenon on the strength of it. An attempt is made in this paper to examine the implications of this fact in very general terms.

Stabilization Control of Hunting Motion of Railway Vehicle Wheelset Using Gyroscopic Damper

2008 ◽  
Vol 14 (1-2) ◽  
pp. 209-230 ◽  
Author(s):  
Hiroshi Yabuno ◽  
Hirokazu Takano ◽  
Hirokazu Okamoto
Keyword(s):  
Railway Vehicle ◽  
Stabilization Control ◽  
Hunting Motion

Results of Investigation of the Properties of Railway Vehicles With the New Design of Wheelsets Using the Computer Models and Field Tests

Joint Rail ◽  
2004 ◽  
Author(s):  
Leonid V. Vinnik ◽  
Guenrikh P. Bourtchak
Keyword(s):  
Computer Model ◽  
Numerical Models ◽  
Field Tests ◽  
Physical Models ◽  
Railway Vehicle ◽  
Nonlinear Creep ◽  
Dynamic Features ◽  
Rail Wear ◽  
Hunting Motion ◽  
Angular Velocities

The results of linking research on analysis of the railway vehicle properties with the new designs of wheelsets, allowing various angular velocities of the tread rotations relative to the hubs by retaining gravitational-frictional torsional connection between them, are considered. Through an analysis of dynamic features during the hunting motion of the vehicle, carried out on the computer model using the nonlinear creep theories, the advantages of this design are found, which include first of all the decrease of wheel and rail wear, and improvement of dynamic features. The issue of metro car motion in the traction mode is specially considered. Tests on physical models and field tests of the tram and metro car verified the results received on numerical models.

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