Dynamic Assessment of Ballastless Track Stiffness and Settlement in High-Speed Railway

Although ballastless track has such advantages as less maintenance and high stability, its big rigidity results in a strong wheel/rail dynamic interaction. In order to study a reasonable stiffness and uneven settlement limit for ballastless track and to optimize the dynamic performance of ballastless track under condition of high-speed running, vehicle together with ballastless track was viewed as an entire coupling system in this study. By adopting numerical simulation, we studied how the stiffness of foundation under rail and uneven settlement of subgrade influence the wheel/rail dynamic interaction. The results show that the reasonable stiffness of foundation under rail is within a range of 20∼30kN/mm, accordingly with a rail deformation within 1.3 ∼ 1.7mm. Through its dynamic analysis under different wavelengths and amplitudes, the uneven settlement of subgrade should be ≤L/1000.

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Study on Reasonable Length of Ballasted-CRTS II Ballastless Track Transition Section on High-Speed Railway Bridge

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.671-674.1301 ◽

2013 ◽

Vol 671-674 ◽

pp. 1301-1305 ◽

Cited By ~ 2

Author(s):

Yu Liu ◽

Guo Tang Zhao

Keyword(s):

High Speed ◽

Stability Index ◽

Dynamic Interaction ◽

Railway Bridge ◽

The Finite Element Method ◽

High Speed Railway ◽

Transition Section ◽

Ballastless Track ◽

Rail Deflection ◽

Random Irregularity

In view of ballasted-CRTSⅡ ballastless track transition section on the bridge of Beijing-Shanghai high-speed railway, the influence of track random irregularity and pier foundation settlement difference on acceleration and stability index of locomotive body are discussed by the finite element method. And then, by using the index of rail deflection gradient to describe the law of dynamic interaction, rail-wheel dynamic response, attenuation distance of locomotive body acceleration and change of sleeper pressure caused by under-rail stiffness difference are analyzed. Finally, the recommended value of reasonable length of transition section is put forwarded.

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Influencing Factors of Dynamic Performance of Jointless Turnout on Bridge in High-Speed Railway

2010 Joint Rail Conference, Volume 1 ◽

10.1115/jrc2010-36114 ◽

2010 ◽

Author(s):

R. Chen ◽

P. Wang ◽

X. P. Chen

Keyword(s):

High Speed ◽

Dynamic Performance ◽

Dynamic Responses ◽

Wheel Load ◽

Longitudinal Gradient ◽

High Speed Railway ◽

Coupling Vibration ◽

Vertical Stiffness ◽

Coupling System ◽

Chinese Standard

Taking the case of 18# turnout (350km/h) laid on 6×32m continuous girder, a dynamic model for coupling system of vehicle and jointless turnout on bridge was established to analyze the factors that affected dynamic performance of jointless turnout on bridge, and several aspects were taken into consideration, i.e. train’s running quality, rail stress of turnout, vibration of turnout and bridge, and deformation, etc. It is shown that influenced by vibration and deformation of bridge, the train, turnout and bridge form a coupling vibration system, whose dynamic responses are stronger than those caused by train/turnout interaction on subgrade. Wheel/rail contact of turnout zone (especially the frog) has great effect on dynamic responses of jointless turnout on bridge, thus the nose rail height of frog should be optimized to mitigate the wheel load transition and its longitudinal gradient. When a train is passing a jointless turnout on bridge, a reasonable vertical stiffness for bridge is the key to keep its safety and comfort; as for the 32m continuous girder, the ratio of deflection to span should be ≤1/9000 under the ZK load (Chinese standard).

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Dynamic Performance of High-Speed Electric Multiple Unit within Multi-Body System Simulation

Recent Patents on Mechanical Engineering ◽

10.2174/2666145412666190923104415 ◽

2019 ◽

Vol 12 (4) ◽

pp. 339-349

Author(s):

Junguo Wang ◽

Daoping Gong ◽

Rui Sun ◽

Yongxiang Zhao

Keyword(s):

High Speed ◽

Rapid Development ◽

Dynamic Performance ◽

Body System ◽

High Speed Railway ◽

Evaluation Indexes ◽

Actual Operation ◽

Multiple Unit ◽

The Stability ◽

Multi Body

Background: With the rapid development of the high-speed railway, the dynamic performance such as running stability and safety of the high-speed train is increasingly important. This paper focuses on the dynamic performance of high-speed Electric Multiple Unit (EMU), especially the dynamic characteristics of the bogie frame and car body. Various patents have been discussed in this article. Objective: To develop the Multi-Body System (MBS) model of EMU, verify whether the dynamic performance meets the actual operation requirements, and provide some useful information for dynamics and structural design of the proposed EMU. Methods: According to the technical characteristics of a typical EMU, a MBS model is established via SIMPACK, and the measured data of China high-speed railway is taken as the excitation of track random irregularity. To test the dynamic performance of the EMU, including the stability and safety, some evaluation indexes such as wheel-axle lateral forces, wheel-axle lateral vertical forces, derailment coefficients and wheel unloading rates are also calculated and analyzed in detail. Results: The MBS model of EMU has better dynamic performance especially curving performance, and some evaluation indexes of the stability and safety have also reached China’s high-speed railway standards. Conclusion: The effectiveness of the proposed MBS model is verified, and the dynamic performance of the MBS model can meet the design requirements of high-speed EMU.

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Mechanical Performance of a Ballastless Track System for the Railway Bridges of High-Speed Lines: Experimental and Numerical Study under Thermal Loading

Materials ◽

10.3390/ma14112876 ◽

2021 ◽

Vol 14 (11) ◽

pp. 2876

Author(s):

Yingying Zhang ◽

Lingyu Zhou ◽

Akim D. Mahunon ◽

Guangchao Zhang ◽

Xiusheng Peng ◽

...

Keyword(s):

High Speed ◽

Thermal Loading ◽

Mechanical Performance ◽

Track Structure ◽

Box Girder ◽

High Speed Railway ◽

Ballastless Track ◽

Track System ◽

Girder Bridge ◽

Track Slab

The mechanical performance of China Railway Track System type II (CRTS II) ballastless track suitable for High-Speed Railway (HSR) bridges is investigated in this project by testing a one-quarter-scaled three-span specimen under thermal loading. Stress analysis was performed both experimentally and numerically, via finite-element modeling in the latter case. The results showed that strains in the track slab, in the cement-emulsified asphalt (CA) mortar and in the track bed, increased nonlinearly with the temperature increase. In the longitudinal direction, the zero-displacement section between the track slab and the track bed was close to the 1/8L section of the beam, while the zero-displacement section between the track slab and the box girder bridge was close to the 3/8L section. The maximum values of the relative vertical displacement between the track bed and the bridge structure occurred in the section at three-quarters of the span. Numerical analysis showed that the lower the temperature, the larger the tensile stresses occurring in the different layers of the track structure, whereas the higher the temperature, the higher the relative displacement between the track system and the box girder bridge. Consequently, quantifying the stresses in the various components of the track structure resulting from sudden temperature drops and evaluating the relative displacements between the rails and the track bed resulting from high-temperature are helpful in the design of ballastless track structures for high-speed railway lines.

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