scholarly journals Study on the Urban Rail Transit Sleeper Spacing Considering Vehicle System

2019 ◽  
Vol 296 ◽  
pp. 01008
Author(s):  
Yu Zou ◽  
Yongpeng Wen ◽  
Qian Sun
Keyword(s):  
High Speed ◽  
Coupling Model ◽  
Vertical Vibration ◽  
Vibration Response ◽  
Urban Rail Transit ◽  
Vehicle Speed ◽  
Vertical Coupling ◽  
Vehicle System ◽  
Spectrum Density ◽  
The Impact

To design the optimal sleeper spacing of the track and reduce the vertical vibration of the rail, the influence of the sleeper spacing on the rail vibration is analysed in the vehicle-track vertical coupling model. By comparing the effects of vehicle speed and load on the vibration response of rails under different sleeper spacings, the importance of vehicle system is pointed out. According to the power spectrum density of the vertical rail displacement, the optimal sleeper spacing under the specific line is proposed, and verified via the vibration decay rate. The results show that the sleeper spacing directly affects the first-order Pinned-pinned vibration of the rail, and the effects of the speed and the load on the vibration response are different. In the low-speed section, the impact of the sleeper spacing on the vibration response is smaller, and the larger spacing can be appropriately selected to reduce the number of sleeper to save costs. However, in the high-speed section, the impact is larger, and the speed and the load should be comprehensively considered to select the optimal sleeper spacing.

Analysis on Impact Loading at Rail Welds at High Speed

2008 ◽  
Author(s):  
Guangwen Xiao ◽  
Xinbiao Xiao ◽  
Zefeng Wen ◽  
Xuesong Jin
Keyword(s):  
Impact Loading ◽  
High Speed ◽  
Hertzian Contact ◽  
Railway Vehicle ◽  
Vehicle Speed ◽  
Explicit Integration ◽  
Normal Forces ◽  
Rail Irregularity ◽  
Multi Body ◽  
The Impact

When a railway vehicle passes through a track with different weld irregularities at high speed, the impact loading of the vehicle coupled with the track is investigated in detail using a coupled vehicle/track model. In this model, a half vehicle is considered and modeled as a multi-body system. In the track model, a Timoshenko beam resting on discrete sleepers is applied to model each rail. Each sleeper is modeled as a rigid body accounting for its vertical, lateral, roll motions. A moving sleeper support model is used to simulate the interaction of the vehicle and the track. The ballast bed is replaced with equivalent masses. The equivalent dampers and springs are used to replace the connections between the parts of the vehicle and track. In calculating the coupled vehicle and track dynamics, Hertzian contact theory and the creep force theory by Shen et al. are, respectively, used to calculate the normal forces and the creep forces between the wheels and the rails. The motion equations of the vehicle-track are solved by means of an explicit integration method. The weld rail irregularity is modeled by setting a local track vertical deviation at a rail weld joint, which is described with a simplified cosine function. In the numerical analysis the effect of the different wavelength, depth, the position of the welded joint in a sleeper span, and vehicle speed is taken into account. The numerical results obtained are greatly useful in the tolerance design of welded rail profile irregularity caused by damage and hand-grinding after rail welding.

Centrifuge Simulation of Wave Propagation due to Vertical Vibration on Shallow Foundations and Vibration Attenuation Countermeasures

2005 ◽  
Vol 11 (6) ◽  
pp. 781-800 ◽  
Author(s):  
K. Itoh ◽  
X. Zeng ◽  
M. Koda ◽  
O. Murata ◽  
O. Kusakabe
Keyword(s):  
Wave Propagation ◽  
High Speed ◽  
Ground Vibration ◽  
Vertical Vibration ◽  
Shallow Foundations ◽  
Testing System ◽  
High Speed Trains ◽  
Railway System ◽  
Environmental Consideration ◽  
The Impact

When constructing a high-speed railway system in an urban area, the reduction of the ground vibration and noise generated by train passages is a vitally important environmental consideration. In this paper we focus on the development of a centrifuge vibration testing system, which can simulate dynamic loading acting on shallow foundations. The system is used to generate vertical vibration similar to that generated by high-speed trains. The characteristics of wave propagation in a shallow circular foundation on sand are investigated. The effects of two types of barriers on vibration reduction are studied. Additionally, the impact of using vibration attenuating materials to build trackbeds is evaluated.

scholarly journals Flexible-Rigid Wheelset Introduced Dynamic Effects due to Wheel Tread Flat

2021 ◽  
Vol 2021 ◽  
pp. 1-21
Author(s):  
Awel Momhur ◽  
Y. X. Zhao ◽  
Liwen Quan ◽  
Sun Yazhou ◽  
Xialong Zou
Keyword(s):  
High Speed ◽  
Statistical Approach ◽  
Impact Load ◽  
Vertical Acceleration ◽  
Vehicle Speed ◽  
Dynamic Impact ◽  
Element Analysis ◽  
Wheel Flat ◽  
Wheel Radius ◽  
The Impact

The widespread faults that occur in railway wheels and can cause a massive dynamic impact are the wheel tread flat. The current work considered changes in vehicle speed or wheel radius deviation and studied the dynamic impact load. The modal technique for the impact evaluation induced by the wheel flat was proposed via the finite element analysis (FEA) software package ANSYS, integrated into a multibody dynamics model of the high-speed train CRH2A (EMU) through SIMPACK. The irregularity track line has developed and depends on the selected simulation data points. Additionally, a statistical approach is designed to analyze the dynamic impact load response and effect and consider different wheel flat lengths and vehicle speeds. The train speed influence on the flat size of the vertical wheel-rail impact response and the statistical approach are discussed based on flexible, rigid wheelsets. The results show that the rigid wheel flat has the highest vertical wheel impact load and is more significant than the flexible wheel flat force. The consequences suggest that the wheelset flexibility can significantly improve vertical acceleration comparably to the rigid wheel flats. In addition, the rendering of the statistical approach shows that the hazard rate, PDF, and CDF influence increase when the flat wheel length increases.

Analysis of Vibration Characteristics of Friction Plate Based on Rigid-Flexible Coupling Model

2013 ◽  
Vol 572 ◽  
pp. 480-484
Author(s):  
Shen Long Li ◽  
Jiang Li Pan ◽  
Hua Bing Yin
Keyword(s):  
Dynamic Model ◽  
High Speed ◽  
Element Model ◽  
Coupling Model ◽  
Vibration Characteristics ◽  
Composition Analysis ◽  
Coupling Vibration ◽  
Flexible Coupling ◽  
Friction Plate ◽  
The Impact

The stability and reliability of the shift friction plate are the main condition to guarantee the normal working for the planetary gearbox. But the failures of the friction plate, such as fracture or broken plastic deformation, often appear during the real vehicle testing process. Currently, most studies focus on chemical composition analysis and fracture analysis for the fractured friction plate, but less study for shock damage. In this paper, we develop a multi-body dynamic model, a finite element model and a rigid-flexible coupling dynamic model to analyze and compare the vibration characteristics of the friction plate with three different support forms. The variation law of the impact force and frequency can be obtained for the tooth portion of the friction plate with different support forms. Finally, it can provide theoretical guidance for studying the failure of friction plate at high speed. Keywords: Friction Plate; Rigid-flexible Coupling; Vibration Characteristics

Prediction of Ground Vibration from High Speed Trains Using a Vehicle–Track–Ground Coupling Model

2016 ◽  
Vol 16 (08) ◽  
pp. 1550051 ◽  
Author(s):  
H. L. Yao ◽  
Z. Hu ◽  
Z. Lu ◽  
Y. X. Zhan ◽  
J. Liu
Keyword(s):  
Fourier Transform ◽  
High Speed ◽  
Dynamic Stiffness ◽  
Ground Vibration ◽  
Coupling Model ◽  
Vehicle Speed ◽  
High Speed Trains ◽  
Rail Irregularity ◽  
The Fourier Transform ◽  
The Time Domain

The dynamically induced ground vibration from high speed trains (HSTs) is investigated using a semi-analytical vehicle–track–ground coupling model. A multi-body vehicle is adopted along with rail irregularity considered in the model. The soil is simulated as a saturated poroelastic half-space with two elastic layers. The coupling system is solved in the transformed domain by applying the Fourier transform, and the dynamic stiffness matrix method is used to deal with the layered soil. The time-domain solutions are obtained by the inverse fast Fourier transform (FFT). The effects of the vehicle speed, observation location, rail irregularity, subgrade-bed stiffness, and vehicle type on the ground vibration are investigated thoroughly. The results show that all these factors can significantly affect the dynamically induced ground vibration.

scholarly journals Effect of wheel polygonalization on the Degree of Non-linearity of dynamic response of high-speed vehicle system

2021 ◽  
pp. 002029402110354
Author(s):  
Chen Shuangxi ◽  
Ni Yanting
Keyword(s):  
Dynamic Response ◽  
Health Monitoring ◽  
Extraction Method ◽  
High Speed ◽  
Vibration Response ◽  
High Speed Train ◽  
Coupled Dynamics ◽  
Vehicle System ◽  
Parameters Extraction ◽  
Non Linear

Polygonalization of the wheel describes the growth of out-of-round profiles of the wheels of railway vehicle. This problem was identified in the 1980s but its mechanism is still not well understood. The wheel-rail disturbance formed by wheel polygonalization will accelerate the fatigue fracture of the key parts of rail vehicles and seriously threaten the safety of rail vehicle. This fact has led to significant efforts in detecting and diagnosing wheel polygonalization, in particular in setting the criteria for health monitoring. Currently, the time-domain feature parameters extraction method based on data statistics and frequency-domain feature parameters extraction method based on spectrum estimation are widely applied to detect wheel polygonalization. However, the basis of spectral estimation is the Fourier transform, which is not good at dealing with non-linear vibration systems (such as vehicle-track coupled system). Aiming at the wheel polygonalization problem existing in high-speed train, the non-linear extent of vibration response of vehicle system caused by wheel polygonalization is analyzed based on vehicle-track coupled dynamics and adaptive data analysis method. A typical high-speed train model is established according to the vehicle-track coupled dynamics theory. The wheel polygonalization model is introduced and vehicle system vibration response is calculated by numerical integration. The vibration response signal is decomposed by empirical mode decomposition (EMD) to produce the intrinsic mode functions (IMFs). By calculating the intra-wave frequency modulation of IMFs, that is, the difference between instantaneous and mean frequencies and amplitudes, the non-linearity of the dynamic response is quantified. Influences of wheel polygonalization on the non-linearity of steady-state and unsteady vibration responses of vehicle system are analyzed in detail. An objective criterion for wheel polygonalization health monitoring based on Degree of Non-linearity is proposed, which provides an effective tool for prognostics and health management of trains.

Dynamic Responses Analysis of Vehicle and Track Based on Different Train Speed

2013 ◽  
Vol 706-708 ◽  
pp. 1314-1318
Author(s):  
Hong Mei Shi ◽  
Zu Jun Yu
Keyword(s):  
High Speed ◽  
Rapid Development ◽  
Coupling Model ◽  
Dynamic Responses ◽  
High Speed Railway ◽  
Vertical Coupling ◽  
Railway Infrastructure ◽  
Train Operation ◽  
Vibration Responses ◽  
Train Speed

With the rapid development of high-speed railway, dynamic interaction between vehicles and track is correspondingly strengthened. Therefore, dynamic responses analysis of the high-speed vehicles and track become more and more important to the train operation safety, riding comfort as well as the maintenance of railway infrastructure. In this paper, vehicle and track vibration equations are separately established based on the vehicle track vertical coupling model. Taking the CRH vehicle running on the existing line as an example, the random vibration responses of the vehicle and track under different running speed are analyzed in time domain through numerical integral method and MATLAB program. According to the results, the velocity of train has more influence on the vibration property of rail and wheelsets than bogie and carbody.

Coupled dynamic analysis of low and medium speed maglev vehicle-bridge interaction using SIMPACK

2020 ◽  
pp. 095440972092567
Author(s):  
Junxiong Hu ◽  
Weihua Ma ◽  
Shihui Luo
Keyword(s):  
Vertical Vibration ◽  
Dynamic Force ◽  
Vehicle Speed ◽  
Coupled Vibration ◽  
Coupled Dynamic Analysis ◽  
Maglev Vehicle ◽  
Vehicle System ◽  
Medium Speed ◽  
Levitation System ◽  
Multi Body

The low- and medium-speed maglev vehicle generally operates on elevated bridges with a levitation gap of only 8--10 mm, which makes it very sensitive to the vehicle--bridge coupled vibration. To conduct the corresponding modeling and simulation with common dynamics tools, an equivalent processing of the levitation system is required. Using the dynamics software SIMPACK, this paper first introduces the methods of building the multi-body vehicle system, levitation control system and the elastic bridge, respectively, in the SIMPACK railway module, levitation control module and SIMBEAM elastomer module, thus providing a modeling idea for the simulation of the active levitation and operation of low- and medium-speed maglev vehicles through multi-span bridges. It then goes on to simulate and analyze the coupled vibration of a 160 km/h low- and medium-speed maglev vehicle passing through 25 m + 25 m double-span continuous bridges. The research results show that the modeling method introduced in this paper can simulate the low- and medium-speed maglev vehicle--bridge coupled vibration phenomenon, which can be affected significantly by the low-order frequency of the elastic bridge, and can also be intensified under the bridge end impact when the vehicle enters and leaves the bridge. As the running speed of the vehicle increases and the dynamic force increases, the vertical vibration amplitudes of the elastic bridge mid-span, the car body as well as the levitation frame approximate a linear fitting with the vehicle speed. The variation amplitudes of the levitation gap and of the electromagnet current approximate a quadratic fitting with the vehicle speed.

scholarly journals Insights into the Effect of WJ-7 Fastener Rubber Pad to Vehicle-Rail-Viaduct Coupled Dynamics

2020 ◽  
Vol 10 (5) ◽  
pp. 1889 ◽  
Author(s):  
Linya Liu ◽  
Zhiyuan Zuo ◽  
Yunlai Zhou ◽  
Jialiang Qin
Keyword(s):  
High Temperature ◽  
High Speed ◽  
Coupling Model ◽  
Peak Frequency ◽  
Dominant Frequency ◽  
Dynamic Responses ◽  
Temperature Sensitive ◽  
Temperature Dependent ◽  
Vertical Coupling

The high-speed railway (HSR) has been a long-term hotspot in both scientific and engineering societies to enhance the long-term high quality HSR service. This study aims to investigate the WJ-7B type small resistance fastener rubber pad applied in HSR, and temperature sweep test is applied to determine the mechanical parameters of the fastener rubber pad, which are hereafter introduced into the vehicle-track-viaduct vertical coupling model via dynamic flexibility method. The track irregularity spectrum is considered as fixed-point excitation to investigate the temperature-dependent effect of fastener rubber pad on the dynamic responses. The results reveal that the rigidity of the fastener rubber pad is low temperature sensitive and high temperature stable, and the temperature variation has little effect on the vertical dynamic responses of the vehicle. The dynamic flexibility of the rail increases in amplitude and the dominant frequency decreases as the temperature of the fastener rubber pad increases. The vertical dynamic responses of the wheel-rail force, the wheelset and the rail-viaduct system gradually decrease as the temperature of the fastener rubber pad increases, and the peak frequency follows the similar rule. While under high temperature circumstances, the temperature dependent stiffness of the fastener rubber pad has little influence on the peak of the dominant frequency in the vertical dynamic response of the track-viaduct system.

Vibration Analysis of High-Speed Vehicles under the Condition of Track Random Irregularity

2011 ◽  
Vol 211-212 ◽  
pp. 525-529 ◽  
Author(s):  
Hong Mei Shi ◽  
Jia Liang Zhou
Keyword(s):  
Differential Equation ◽  
Numerical Simulation ◽  
Vibration Analysis ◽  
High Speed ◽  
Simulation Method ◽  
Coupling Model ◽  
Vertical Coupling ◽  
Vehicle Components ◽  
Track Irregularity ◽  
Random Irregularity

Track irregularity is the most important excitation source of wheel-rail system. The vibration characteristics of vehicle components and track components are analyzed in this paper under the condition of track irregularity by establishing the vehicle - track vertical coupling model. And the establishment of vibration differential equation and numerical simulation method for solving vibration response are described in detail. Finally, the results are given by MATLAB. The method is of great significance for evaluating the dynamic track irregularity and vehicle’s vibration at different running speeds.

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