scholarly journals Analysis of Dynamic Characteristics of Deformed Concrete Slab Track on Transition Zone in High-Speed Train Line According to Train Speeds

2020 ◽  
Vol 10 (20) ◽  
pp. 7174
Author(s):  
Sungbum Park ◽  
Ja Yeon Kim ◽  
Jongwon Kim ◽  
Sehee Lee ◽  
Kook-Hwan Cho
Keyword(s):  
Numerical Analysis ◽  
Dynamic Characteristics ◽  
High Speed ◽  
Concrete Slab ◽  
Field Tests ◽  
Analysis Model ◽  
Transition Zones ◽  
Slab Track ◽  
Speed Range ◽  
Train Speed

A concrete track, such as Rheda 2000 is commonly used in high-speed railways in Korea, Germany, China, etc., to enhance the operational safety of trains and to reduce the maintenance costs. However, when settlement of embankment or a crack in the concrete slab track occurs, the durability of the concrete track deteriorates significantly. Transition zones are considered to be vulnerable and are often deformed in railway embankments. The characteristics of track support stiffness and stresses on the rail in a deformed section are different from those in an undeformed section. In this study, a field measurement and numerical analysis were carried out to identify the dynamic response on transition zones where the track is deformed. A numerical analysis model was built to simulate the deformed concrete slab track, and it was compared with measured data from field tests for verification. The field tests to measure the stresses on the rail were performed in a train speed range from 280 to 300 km/h. According to the numerical analysis, the dynamic characteristics of the track varied with train speeds, which were then compared with the allowable stresses of the concrete slab track.

Fatigue life evaluation of continuous welded rails on concrete slab track in Korea high-speed railway

2018 ◽  
Vol 21 (13) ◽  
pp. 1990-2004 ◽  
Author(s):  
Deok-Yong Sung ◽  
Sung-Cheon Han
Keyword(s):  
Fatigue Life ◽  
High Speed ◽  
Concrete Slab ◽  
Maintenance Cost ◽  
Surface Irregularity ◽  
Bending Stress ◽  
High Speed Railway ◽  
Slab Track ◽  
Short Period ◽  
Train Speed

There is a rapidly increasing demand for continuous welded rails. Continuous welded rails provide a more suitable installation on concrete slab tracks and more rapid and smooth movement and reduce overall maintenance cost. During the relatively short period in which concrete slab tracks have been used in Korea, there has been no documented case of rail fracture caused by repeated loading. This makes the evaluation of rail fatigue life using field data more difficult. In this study, the rail bending stress developed during high-speed train operation is obtained through analysis of vehicle–track interaction, and the correlation is analyzed by performing multiple regression analysis on train speed and rail surface irregularities. Equations for predicting the rail bending stress with regard to train speed and rail surface irregularity were derived. The effects of vehicle speed, track support stiffness, and fracture probability on the fatigue life of continuous welded rails on a concrete slab track in Korea high-speed railway were analyzed.

Dynamic Characteristic Analysis and Validation of Spindle Assembly of High Speed Machine Tool

2009 ◽  
Vol 407-408 ◽  
pp. 135-139
Author(s):  
Yao Man Zhang ◽  
Xiu Li Lin ◽  
Chun Shi Liu ◽  
Guang Qi Cai
Keyword(s):  
Machine Tool ◽  
Dynamic Characteristics ◽  
High Speed ◽  
Spindle Assembly ◽  
Analysis Model ◽  
Characteristic Analysis ◽  
Element Analysis ◽  
Nc Machine Tool ◽  
Nc Machine ◽  
High Speed Machine

To design a machine tool successfully, its essential parts should be analyzed and evaluated after design but before prototype being made. The spindle assembly is one of the most essential parts of high speed machine tool, so how the dynamic characteristics of the spindle assembly affect the performance of high speed NC machine tool are of great significance and should be studied. This paper’s research is based on a high speed machine tool manufactured by some plant. The finite element analysis model of the spindle assembly of the high speed machine tool was developed by taking the advantage of the spring-damper element to simulate the bearing supports. The modal analysis was made to confirm the dynamic characteristics of the spindle assembly, and the results were compared with the testing ones.

scholarly journals Design theories and maintenance technologies of slab tracks for high-speed railways in China: a review

2021 ◽  
Vol 3 (4) ◽  
Author(s):  
Juanjuan Ren ◽  
Shijie Deng ◽  
Kaiyao Zhang ◽  
Wei Du ◽  
Qinghong Wu
Keyword(s):  
High Speed ◽  
Field Tests ◽  
Research Trend ◽  
Future Research ◽  
Stable Operation ◽  
High Speed Railway ◽  
Slab Track ◽  
Design Theories ◽  
Future Direction

Abstract The durability and reliability of slab track structures are essential for the long-term safety and stable operation of high-speed railways. In order to provide a solid theoretical basis and technical reference for the advancement of high-speed railway quality, this paper comprehensively discusses design theories of slab track structures, service performance evolution and maintenance technologies, and reviews the innovation happening in the industry. On top of that, the damage evolution, fatigue features and durability of slab tracks, which are highly relevant to serviceability, are summarized, and the future research trend of slab track service behaviours is pointed out. In addition, this paper summarizes the rules of establishing standards for damage maintenance, typical solutions for repairing damage and methods of evaluating the maintenance outcomes that combine field tests and numerical simulations. It also envisions a future direction where advanced testing technologies would assist the evaluation of maintenance effects.

scholarly journals DYNAMIC PERFORMANCE OF LOW VIBRATION SLAB TRACK ON SHARED HIGH-SPEED PASSENGER AND FREIGHT RAILWAY

Transport ◽  
2018 ◽  
Vol 33 (3) ◽  
pp. 669-678
Author(s):  
Qinglie He ◽  
Chengbiao Cai ◽  
Shengyang Zhu ◽  
Jiawei Zhang ◽  
Wanming Zhai
Keyword(s):  
Finite Element ◽  
High Speed ◽  
Vibration Isolation ◽  
Dynamic Models ◽  
Concrete Slab ◽  
Dynamic Performance ◽  
Tension Stress ◽  
Slab Track ◽  
Track System ◽  
Supporting Layer

This work investigates dynamic performance of a low vibration slab track on a shared high-speed passenger and freight railway, and an optimal modulus of the isolation layer (rubber pad) is proposed to meet the adaptability of the track system under the dynamic actions of high speed passenger and heavy axle-load freight trains. First, detailed finite element models of the slab track with and without the rubber pad between concrete slab and supporting layer are established by using software ANSYS. Further, coupled dynamic models of passenger/freight vehicle–low vibration/tradition slab track system are developed to calculate the wheel–rail forces, which are utilized as the inputs to the finite element model. Finally, the dynamic characteristics of the low vibration slab track, the specific function of the rubber pad, and the optimal modulus of the rubber pad are studied in detail. Results show that the interaction force between the freight vehicle and low vibration slab track is more significant because of the heavy axle-load, which leads to larger vertical stress amplitudes of each track layer. Whereas the accelerations of track components induced by the passenger vehicle are much larger than those induced by the freight vehicle, due to the much faster speed that can generate high wheel–rail interaction frequency. The rubber pad of the slab track does not play a role in attenuating slab vibration; instead it causes an increase of slab acceleration and its surface tension stress. However, the rubber pad can decrease the supporting layer acceleration and the slab compression stress, which plays a significant role in vibration isolation and buffers the direct impact force on the slab caused by vehicle dynamic load. To ensure a reasonable vibration level and dynamic stress of the slab track, the optimal modulus of the rubber pad is suggested to be 3÷7.5 MPa.

Effect of Flexible Damped Bearing-Supports on the Dynamic Stability of High-Speed Turbochargers

2013 ◽  
Author(s):  
A. Alsaeed ◽  
G. Kirk ◽  
S. Bashmal
Keyword(s):  
Dynamic Stability ◽  
Dynamic Characteristics ◽  
High Speed ◽  
Element Model ◽  
Dynamic Coefficients ◽  
Speed Range ◽  
Rotor Bearing ◽  
The Stability ◽  
The Finite Element Model ◽  
Bearing System

The aim of this study is to analytically design flexible damped bearing-supports in order to improve the dynamic characteristics of the rotor-bearing system. The finite-element model of the turbocharger rotor with linearized bearing dynamic coefficients is used to solve for the logarithmic decrements and hence the stability map. The design process attempts to find the optimum dynamic characteristics of the flexible damped bearing-support that would give best dynamic stability of the rotor-bearing system. The method is successful in greatly improving the dynamic stability of the turbocharger and may also lead to a total linear stability throughout the entire speed range when used besides the enhanced-performance hydrodynamic bearings.

Simulation Analysis of Bidirectional Fluid-Solid Coupling for Hydrodynamic Coupling

2015 ◽  
Vol 744-746 ◽  
pp. 1128-1132 ◽  
Author(s):  
Wen Xing Ma ◽  
Xiao Wen Shen ◽  
Xiu Quan Lu ◽  
Long Fei Ji
Keyword(s):  
Numerical Analysis ◽  
Dynamic Characteristics ◽  
Structural Design ◽  
Theoretical Basis ◽  
High Speed ◽  
Simulation Analysis ◽  
Turbine Blades ◽  
Great Power ◽  
Analysis Method ◽  
Hydrodynamic Coupling

In this paper, bi-directional fluid-solid coupling numerical analysis method was introduced into the structural design of hydrodynamic coupling, this method was adopted to simulate the impeller strength and analyze the dynamic characteristics of the turbine blades, as well as the influences of turbine blades deformation the inside flow filed of hydrodynamic coupling was discussed. The work provides a theoretical basis for the design of the hydrodynamic coupling with the great power and high speed.

Experimental Study on Vertical Stiffness of WJ-8 Fastener for High-Speed Railway

2015 ◽  
Vol 723 ◽  
pp. 100-103 ◽  
Author(s):  
Can Liu ◽  
Zhi Ping Zeng ◽  
Jia Yu Yuan ◽  
Bin Wu ◽  
Kun Teng Zhu
Keyword(s):  
High Speed ◽  
Plate Theory ◽  
Vertical Displacement ◽  
Track Structure ◽  
Static Stiffness ◽  
Analysis Model ◽  
Element Analysis ◽  
Vertical Stiffness ◽  
Slab Track ◽  
Ballastless Track

The rail vertical displacement of CRTSII slab track structure under vertical static loads was analyzed in this paper by using 1:1 full-scale track model, based on which the WJ-8 fastener vertical static stiffness was calculated, and the rationality of the fastener vertical stiffness values and the relationship between the values and load were studied. According to the beam-plate theory and beam-solid theory for slab ballastless track, a finite element analysis model of CRTSII slab track structure was established. The rail vertical displacement under the same case as test was calculated by using the measured fastener vertical stiffness value. The rationality of the method for testing and the fastener vertical static stiffness is verified through comparing the calculated values with experimental ones.

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