scholarly journals Random Field Modeling of Track Irregularity of Beijing-Guangzhou High-Speed Railway with Karhunen-Loève Expansion

2015 ◽  
Vol 11 (6) ◽  
pp. 521437 ◽  
Author(s):  
Mengyi Zhu ◽  
Xiaohui Cheng ◽  
Lixin Miao ◽  
Xinya Sun
Keyword(s):  
Random Field ◽  
High Speed ◽  
High Speed Railway ◽  
Field Modeling ◽  
Track Irregularity

scholarly journals The Influence of an Integration Time Step on Dynamic Calculation of a Vehicle-Track-Bridge under High-Speed Railway

Mathematics ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 431
Author(s):  
Junjie Ye ◽  
Hao Sun
Keyword(s):  
High Speed ◽  
Coupled Model ◽  
Short Wave ◽  
Integration Time ◽  
Vertical Acceleration ◽  
Dynamic Calculation ◽  
Time Step ◽  
High Speed Railway ◽  
Track Irregularity ◽  
Track Bridge

In order to study the influence of an integration time step on dynamic calculation of a vehicle-track-bridge under high-speed railway, a vehicle-track-bridge (VTB) coupled model is established. The influence of the integration time step on calculation accuracy and calculation stability under different speeds or different track regularity states is studied. The influence of the track irregularity on the integration time step is further analyzed by using the spectral characteristic of sensitive wavelength. According to the results, the disparity among the effect of the integration time step on the calculation accuracy of the VTB coupled model at different speeds is very small. Higher speed requires a smaller integration time step to keep the calculation results stable. The effect of the integration time step on the calculation stability of the maximum vertical acceleration of each component at different speeds is somewhat different, and the mechanism of the effect of the integration time step on the calculation stability of the vehicle-track-bridge coupled system is that corresponding displacement at the integration time step is different. The calculation deviation of the maximum vertical acceleration of the car body, wheel-sets and bridge under the track short wave irregularity state are greatly increased compared with that without track irregularity. The maximum vertical acceleration of wheel-sets, rails, track slabs and the bridge under the track short wave irregularity state all show a significant declining trend. The larger the vibration frequency is, the smaller the range of integration time step is for dynamic calculation.

Stochastic Transverse Earthquake-Induced Damage Track Irregularity Spectrum Considering the Uncertainty of Track-Bridge System

2021 ◽  
pp. 2140004
Author(s):  
Yulin Feng ◽  
Yu Hou ◽  
Lizhong Jiang ◽  
Wangbao Zhou ◽  
Jian Yu ◽  
...  
Keyword(s):  
Simulation Model ◽  
Traffic Safety ◽  
High Speed ◽  
Residual Deformation ◽  
High Speed Railway ◽  
Marquardt Algorithm ◽  
Earthquake Action ◽  
Track Irregularity ◽  
Track Bridge ◽  
Bridge System

The track irregularity spectrum of longitudinally connected ballastless track (LCBT)-bridge systems of high-speed railway was proposed in this paper. First, a simulation model of an LCBT-continuous girder bridge was established by considering the influences of approach bridges and subgrade with track structure. Further, a large number of sample analyses were carried out by taking into account the uncertainty of LCBT-bridge systems and stochastic behaviors of ground motions based on the simulation model. The damage laws of residual deformation of track-bridge system after earthquake actions were studied. Then, an interlayer deformation coordination relationship (IDCR) considering the track irregularity caused by earthquake-induced damage of bearings was developed, and the superposed track irregularity samples were obtained. Finally, by using the improved Blackman–Turkey method and Levenberg–Marquardt algorithm, the LCBT irregularity spectrum, track irregularity spectrogram, track irregularity limit spectrum, and a fitting formula for the track irregularity spectrum on a bridge after the action of earthquakes were obtained. Results obtained from the fitting formula and IDCR were compared, and they indicated that tracks undergone significant high-frequency irregularity diseases after the earthquake action. It was found that the track irregularity spectrum could be roughly divided into three ranges: high-, medium- and low-frequency wavebands. Consequently, this led to an application of a three-segment power function for the fitting of the track irregularity spectrum after the earthquake action. The track irregularity spectrum after the action of earthquakes provides an important theoretical basis for the establishment of seismic design methods for high-speed railway bridges based on the traffic safety performance.

scholarly journals Improvement and In-Situ Application of an Evaluation Method of Ballasted-Track Condition Using Digital 2-D Image Analysis

2020 ◽  
Vol 10 (21) ◽  
pp. 7946
Author(s):  
Bongsik Park ◽  
Yeong-Tae Choi ◽  
Hyunmin Kim
Keyword(s):  
Image Analysis ◽  
High Speed ◽  
Evaluation Method ◽  
Recognition Rate ◽  
High Speed Railway ◽  
Analysis Methods ◽  
Track Condition ◽  
Ballasted Track ◽  
Track Irregularity

The advancement in digital image analysis methods has led to the development of various techniques, i.e., quantification of ballast gravel abrasion. In this study, the recognition rate of gravel aggregates has been significantly increased by improving the image analysis methods. The correlation between the track quality index (TQI), which is the standard deviation of vertical track irregularity and represents the condition of a high-speed railway, and the number of maintenance works was analyzed by performing an image analysis on the samples collected from various locations of a high-speed railway. The results revealed that roundness has the highest correlation with the TQI, whereas sphericity has the highest correlation with the number of maintenance works. The ballast replacement would be performed to improve maintenance efficiency if the abrasion of the ballast aggregates becomes approximately 10%.

Study on Methods of Lateral Deviation of Track for Static Inspecting in High-Speed Railway

2014 ◽  
Vol 638-640 ◽  
pp. 1195-1206
Author(s):  
Yang Teng Long Li ◽  
Min Yi Cen ◽  
Xuan Bai
Keyword(s):  
Newton’S Method ◽  
Newton's Method ◽  
High Speed ◽  
Measurement Data ◽  
Railway Track ◽  
Transition Curve ◽  
Lateral Deviation ◽  
High Speed Railway ◽  
Track Irregularity ◽  
Circular Curve

According to the critical factor of railway track geometric irregular, the deformations of track can be controlled. The lateral deviation is the key to determine the railway track irregularity. Currently, in the static inspected methods, the combined method of geodetic surveys and track surveying trolleys (inspecting instruments for static geometry parameter of track) is widely used in high-speed railway. Depending on some tests, the model of track irregularity in track surveying trolleys can be reconstructed by another method. According to the special features of track of high-speed railway, it is necessary to study on the accurate and effective lateral deviation algorithm which is suitable for the precise track inspection of high-speed railway. Based on some existing methods of construction layout in highway, the primary contents of this paper are: (1) reduces those methods to three algorithms, such as the Longitudinal Deviation Algorithm with Composite Simpson rule (LDACS), the Distance Function Algorithm of Newton’s method (DFAN) and Normal Perpendicular to Tangent Algorithm of Newton’s method (NPTAN), and (2) completes the algorithm steps of DFAN and NPTAN on circular curve, and proves the results of two algorithms on circular curve same, and (3) proposes the three algorithms to calculate lateral deviation and mileage of any rail detection points for inspecting the static geometric state of track in high-speed railway. Depending on some simulation data, the experimental results are: (1) the calculations of DFAN, NPTAN and LDACS, in which the number of subintervals of equal greater than or equal to five, meet the accuracy of the precise track detection of high-speed railway, and (2) the difference mileage and lateral deviation between DFAN and NPTAN are less than 0.001 mm, and (3) the efficiency of those algorithms is very considerable and the efficiency of DFAN is basically the same with NPTAN and higher than LDACS, and (4) the longer the transition curve is, the lower the efficiency and accuracy of DFAN and NPTAN are. The bigger the radius is, the higher the accuracy of LDACS is. According to the measurement data of the Chengdu Dujiangyan Railway Line (Cheng Guan Line), the above mentioned results of (1) and (2) can be proved correctly.

A Study on the Reduction Methods of the Track Irregularity in High Speed Railway

2013 ◽  
Vol 13 (5) ◽  
pp. 285-290
Author(s):  
Tae-Ku Kang ◽  
Kyung-Min Yun ◽  
Il-Yoon Choi ◽  
Nam-Hyoung Lim
Keyword(s):  
High Speed ◽  
High Speed Railway ◽  
Reduction Methods ◽  
Track Irregularity

A Measuring Method of Track Irregularity for High-Speed Railway Based on Dual-Frequency Laser Interference Technique

2013 ◽  
Vol 552 ◽  
pp. 446-451
Author(s):  
Wen Jun He ◽  
Yue Gang Fu ◽  
Yang Zheng ◽  
Lei Zhang ◽  
Jia Ke Wang ◽  
...  
Keyword(s):  
High Speed ◽  
Reference Method ◽  
Measuring Method ◽  
Dual Frequency ◽  
Laser Interference ◽  
High Speed Railway ◽  
Laser Alignment ◽  
Track Irregularity ◽  
Frequency Laser ◽  
Ray Path

A new measuring method of track irregularity for high-speed railway is proposed by using dual-frequency laser interference technique. The linear deviation between the phase-locked gauging head and the center line of the railway route can be calculated by comparing the phase difference variation of the laser beat signal in the test ray path and the reference ray path when the portable track inspection car is moving forward along the track. While we use laser ranging technique to measure gauge, after processing data, the static irregularity of track will be acquired by changing straightness deviation of phase-locked gauging head into straightness deviation of left-right two tracks. The method is different from the existing techniques for detecting high-speed railway irregularity, such as the inertial reference method, the measuring method of chord and the method of laser alignment; it utilized the accuracy of the time to accomplish the high-precision measurement of the space and achieved innovation in theory.

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