scholarly journals Study on a Heuristic Wheelset Structure without Rail Corrugation on Sharply Curved Tracks

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
G. M. Mei ◽  
G. X. Chen ◽  
S. Yan ◽  
R. X. Chen
Keyword(s):  
Difficult Problem ◽  
The Self ◽  
Potential Solution ◽  
Parameter Sensitivity Analysis ◽  
Active Method ◽  
Rail Corrugation ◽  
Incidence Trends ◽  
Track System ◽  
Railway Industry ◽  
Excited Oscillation

Rail corrugation on low rails of sharp railway curves is still a difficult problem to solve worldwide. Nearly all low rails of the sharp railway curves incur rail corrugation. In the present study, an active method to remedy rail corrugation was studied. From the viewpoint of the frictional self-excited oscillation of a wheelset-track system causing rail corrugation, the effect of wheelset structures on rail corrugation was studied. Three frictional self-excited oscillation models of wheelset-track systems with different wheelset structures were established, which include a heuristic wheelset structure and two being used in the railway industry. The incidence trends of the self-excited oscillations of these three wheelset-track systems were studied. It was found that the wheelset structure has an important effect on rail corrugation, and that the heuristic wheelset structure can restrain or get rid of rail corrugation. With the parameter sensitivity analysis, it was found that when the friction coefficient between the wheel and rail, rail gauge, rail cant, and sleeper span changes to some extent, the heuristic wheelset structure is robust enough to prevent rail corrugation. The proposed heuristic wheelset structure can be used as a potential solution to rail corrugation on sharply curved tracks.

scholarly journals Friction-Induced Vibration of a Railway Wheelset-Track System and Its Effect on Rail Corrugation

Lubricants ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 18
Author(s):  
Guangxiong Chen
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Element Model ◽  
The Self ◽  
3D Finite Element ◽  
Rail Corrugation ◽  
Track System ◽  
Excited Vibration ◽  
Creep Force ◽  
Friction Induced Vibration

In the present study, the effect of the radius of railway curved tracks on the slip of a wheel on a rail is studied. A 3D finite-element model of a wheelset-track system is established when the creep force between the wheel and rail is saturated. The occurrence propensity of the self-excited vibration of the wheelset-track system is predicted. It is concluded that the radius of curved tracks has a strong effect on the slip of wheels on rails. In the tightly curved tracks, the slip of the wheel of the leading wheelset on the rail always occurs. The wheelset-track system has a strong occurrence propensity for unstable vibrations on the tightly curved tracks. The accuracy of the rail corrugation prediction based on the unstable vibrations of wheelset-track systems is determined to be 85–90% or higher.

Field measurement and model prediction of rail corrugation

2019 ◽  
Vol 234 (4) ◽  
pp. 381-392 ◽  
Author(s):  
GX Chen ◽  
S Zhang ◽  
BW Wu ◽  
XN Zhao ◽  
ZF Wen ◽  
...  
Keyword(s):  
Finite Element ◽  
Field Test ◽  
Model Prediction ◽  
Field Measurement ◽  
The Self ◽  
Finite Element Models ◽  
Rail Corrugation ◽  
Track System ◽  
Excited Vibration ◽  
Good Agreement

In a field test, three corrugation profiles of rails and their corresponding vibrations were measured, and the wavelengths and frequencies of rail corrugations were obtained. In the model prediction, finite-element models of the self-excited vibrations corresponding to three different wheelset–track systems were established. The corrugation frequencies of these models were predicted, and a comparison between the measured and the predicted corrugation frequencies showed that they are in good agreement. It can be concluded that the self-excited vibration of a wheelset–track system can cause rail corrugation. A benchmark condition for the validation of rail corrugation models is proposed.

A New Mechanism for Squealing Noise and Friction-Induced Vibrations in the Railway Industry

2010 ◽  
Author(s):  
G. X. Chen ◽  
Z. R. Zhou
Keyword(s):  
Time Delay ◽  
Element Model ◽  
Test Results ◽  
Motion Stability ◽  
Rail Corrugation ◽  
Track System ◽  
Excited Vibration ◽  
Railway Industry ◽  
Model Of Friction ◽  
Friction Induced Vibration

In the paper, a new mechanism for squealing vibration based on the time delay concept of friction is introduced. Firstly, several test results on the time delay between the varying normal force and the consequent varying friction are presented and discussed. Secondly, the motion stability of a friction system with the time delay is analyzed in theory. The result shows that the friction system may become unstable in the presence of the time delay. Thirdly, the advantages and disadvantage of the new mechanism are discussed. The remaining part of the paper will present several research advances in the application of friction-induced vibration theory in the railway industry. In the authors’ work, a finite element model of friction self-excited vibration of a railway wheelset-track system is established. The motion stability of the model is analyzed. Numerical results show that friction between the wheel and rail easily causes self-excited vibration of a railway wheelset-track system. The relation between the rail corrugation and friction-induced vibration is discussed. Finally, the field test results in Subway line 4 of Beijing are presented. The test results show that there exists self-excited vibration of a railway wheelset-track system when vehicles negotiate sharp curved tracks.

Erosion Experiment of Self-Excited Oscillation Pulsed Jet

2014 ◽  
Vol 937 ◽  
pp. 614-619
Author(s):  
Chuan Lin Tang ◽  
Jie Pei ◽  
Dong Hu ◽  
Xiao Ting He
Keyword(s):  
Significant Influence ◽  
Cavity Length ◽  
Experimental Studies ◽  
The Self ◽  
Erosion Depth ◽  
Pulsed Jet ◽  
Excited Oscillation ◽  
Erosion Effect ◽  
Erosion Volume ◽  
Peak Value

In order to improve the erosion effect of jet under submergence condition, experimental studies of erosion generated from the self-excited pulsed jet was carried out by using developed self-excited oscillation nozzle. The erosion volume and depth of pulsed jet were measured and taking mortar block as an erosion part. The results were that the standoff has significant influence on erosion effect. The erosion volume firstly decreases with increases in cavity length and then increases to a peak value. Erosion volume of pulsed jet is significantly higher than that of continuous jet, the erosion depth of two jet has slight difference.

Fatigue of Metal Free Reed due to Self-Excited Oscillation

2008 ◽  
Vol 33-37 ◽  
pp. 267-272
Author(s):  
Yoshinobu Shimamura ◽  
Keiichiro Tohgo ◽  
Hiroyasu Araki ◽  
Yosuke Mizuno ◽  
Shoji Kawaguchi ◽  
...  
Keyword(s):  
Fatigue Testing ◽  
The Self ◽  
Fatigue Properties ◽  
Bending Fatigue ◽  
Metal Free ◽  
Mass Damper ◽  
Excited Oscillation ◽  
Analytical Research ◽  
Fatigue Characteristics ◽  
Good Agreement

Metal free reeds are used for musical instruments like harmonica. Free reeds are small, thin cantilevers, and oscillate by blowing air. It is reported that free reeds break due to fatigue during play. In order to elongate the life of free reeds, the fatigue properties should be investigated and a motion analysis method should be developed. The experimental and analytical research on metal free reed, however, has been rarely reported. In this study, two types of fatigue testing machines were developed to obtain basic fatigue characteristics. The fatigue testing machines are designed for bending fatigue of actual free reeds whose thickness is less than 400 μm. An S-N diagram is successfully obtained up to 107 cycles by using the developed fatigue testing machines. The fracture surfaces of fatigued specimens are in good agreement with those of free reeds failed in use. Then, an analytical method for the self-excited oscillation of free reeds was developed based on a mass-damper-spring model. The proposed method can take account for the shape of free reed. The self-excited oscillation of free reeds with different shape are analyzed and in good agreement with experimental results.

Theoretical investigation into the measurability of rail unevenness and corrugation using the dynamic response of axle box and bogie

2020 ◽  
pp. 095440972092321
Author(s):  
Yurong Wang
Keyword(s):  
Dynamic Response ◽  
Standing Waves ◽  
Vehicle Speed ◽  
Long Distance ◽  
Rail Corrugation ◽  
Track Maintenance ◽  
Track System ◽  
Measurement Results ◽  
Ballasted Track ◽  
Rail Irregularity

Monitoring track unevenness is important for noise and vibration control and track maintenance. Rail corrugation and shorter wavelength track unevenness can be measured using the corrugation analysis trolley, but it is not suitable for measurement over long distance. It is of great significance to study the dynamic behavior of the response of the axle box and bogie to the unevenness excitation for a better understanding of the measurement results. In this paper, the dynamic response of the axle box and bogie to the unevenness excitation is analyzed in the frequency domain by taking account of multiple wheel–rail interactions, which is the case in practice. The response of the axle box and bogie is found to be affected by the so-called P2 resonances at low and medium frequencies and the standing waves of rail vibration at higher frequencies due to the multiple wheel–rail interactions. Based on the analysis of the response of the axle box and bogie, the measurability of track unevenness is discussed. Results show that the measurement of rail unevenness using the axle box response is mainly limited by the P2 resonance. The frequency range of measurement for the ballasted track studied is estimated to be 1–35 Hz, corresponding to the measurable unevenness wavelength of 0.6–20 m (or longer) at a vehicle speed of 20 m/s. Above 200 Hz, the standing waves of rail vibration will cause serious uncertainty in the measurement of short wavelength rail irregularity using the axle box response for the resilient track. Short pitch rail corrugation, however, can be evaluated using the axle box response due to its strong correlation with certain modes of the wheel–track system.

Stabilization of a flexible pipe conveying fluid with an active boundary control method

2020 ◽  
Vol 26 (19-20) ◽  
pp. 1824-1834
Author(s):  
Beiming Yu ◽  
Hiroshi Yabuno ◽  
Kiyotaka Yamashita
Keyword(s):  
Flow Velocity ◽  
Control Method ◽  
Bending Moment ◽  
The Self ◽  
Pipe Conveying Fluid ◽  
Stabilization Method ◽  
Critical Flow Velocity ◽  
Complex Eigenvalues ◽  
Excited Oscillation ◽  
Conveying Fluid

A method of stabilizing the self-excited oscillation of a cantilevered pipe conveying fluid because of non–self-adjointness is proposed theoretically and experimentally. Complex eigenvalues denoting the natural frequency and damping of the system vary with an increase in the flow velocity. When the flow velocity exceeds a critical value, the flow-generated damping becomes negative and the pipe is dynamically destabilized. The complex eigenvalues with respect to flow velocity are affected by boundary conditions. We, thus, propose a stabilization control actuating the boundary condition. The stabilization method is carried out by applying a bending moment proportional to the bottom displacement of the pipe. The effect of the proposed control method is shown by investigating the stability for the three lowest modes of the system depending on the feedback gain. It is theoretically clarified that the critical flow velocity is increased by the proposed control method. Furthermore, experiments are performed using a fluid conveying pipe with two piezoactuators at the downstream end. The piezoactuators apply a bending moment at the downstream end of the pipe according to the theoretically proposed method. Experimental results verify that the proposed stabilization method suppresses the self-excited oscillation.

Control Method for Elimination of Self–Excited Oscillations during Turning

2010 ◽  
Vol 164 ◽  
pp. 171-176 ◽  
Author(s):  
Tomáš Březina ◽  
Jan Vetiška ◽  
Petr Blecha ◽  
Pavel Houška
Keyword(s):  
Tool Wear ◽  
Computer Model ◽  
Pid Controller ◽  
Control Method ◽  
The Self ◽  
Machining Process ◽  
Geometric Accuracy ◽  
Turning Process ◽  
Machined Surface ◽  
Excited Oscillation

The oscillations occurring between the tool and the machined area during the turning process lead to degradation of the machined surface, cause poor geometric accuracy, accelerate tool wear and generate noise. This paper deals with the possibility of elimination of these self-excited oscillations by changing the parameters of the turning process. On the basis of the regenerative principle of self-excited oscillation generation, a computer model of the machining process was developed. Furthermore, a PID controller was proposed to control the compensation of the vibrations and its suitability for elimination of the self-excited oscillations was verified experimentally.

Efficiency Improvement of an Automatic Ball Balancer

2012 ◽  
Vol 134 (2) ◽  
Author(s):  
Yukio Ishida ◽  
Tomonori Matsuura ◽  
Xiao Long Zhang
Keyword(s):  
Critical Speed ◽  
Vibration Suppression ◽  
The Self ◽  
The Other ◽  
Efficiency Improvement ◽  
Cylindrical Chamber ◽  
Rotor Systems ◽  
Speed Range ◽  
Excited Oscillation ◽  
Inside Wall

An automatic ball balancer is a unique vibration suppression device for rotor systems. Theoretically, two balls in a cylindrical chamber of the rotor are located at the optimal positions on the opposite side to the unbalance and cancel the unbalance automatically in the super-critical speed range. However, this device is not used widely due to two malfunctions. One is the influence of friction. Due to the inevitable friction between the balls and the inside wall of the channel, the balls stop near the optimal positions and do not balance the rotor perfectly. The other is the self-excited oscillation which occurs near and above the major critical speed. The objectives of the present paper are to clarify the fundamental characteristics of a ball balancer and to introduce some simple methods to eliminate these malfunctions.

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