Moving element analysis of discretely supported high-speed rail systems

2017 ◽  
Vol 232 (3) ◽  
pp. 783-797 ◽  
Author(s):  
Jian Dai ◽  
Kok Keng Ang ◽  
Minh Thi Tran ◽  
Van Hai Luong ◽  
Dongqi Jiang
Keyword(s):  
High Speed ◽  
Railway Track ◽  
High Speed Train ◽  
Element Analysis ◽  
High Speed Rail ◽  
Mass System ◽  
Rail System ◽  
Rail Systems ◽  
Track System ◽  
The Difference

In this paper, a computational scheme in conjunction with the moving element method has been proposed to investigate the dynamic response of a high-speed rail system in which the discrete sleepers on the subgrade support the railway track. The track foundation is modeled as a beam supported by uniformly spaced discrete spring-damper units. The high-speed train is modeled as a moving sprung-mass system that travels over the track. The effect of the stiffness of the discrete supports, train speed, and railhead roughness on the dynamic behavior of the train–track system has been investigated. As a comparison, the response of a continuously supported high-speed rail system that uses a foundation stiffness equivalent to that of a discretely supported track has been obtained. The difference in results between the “equivalent” continuously supported and the discretely supported high-speed rails has been compared and discussed. In general, the study found that a high-speed train that travels over a discretely supported track produces more severe vibrations than that travels over a continuously supported track of equivalent foundation stiffness.

scholarly journals Moving element analysis of high-speed rail system accounting for hanging sleepers

2018 ◽  
Vol 148 ◽  
pp. 05007 ◽  
Author(s):  
Jian Dai ◽  
Kok Keng Ang ◽  
Dongqi Jiang
Keyword(s):  
Dynamic Response ◽  
High Speed ◽  
High Speed Train ◽  
Train Track ◽  
Element Analysis ◽  
High Speed Rail ◽  
Factors Affecting ◽  
Rail System ◽  
Track System ◽  
Ballasted Track

It is very common in the ballasted track system that sleepers are not well supported by the ballast materials due to the uneven settlement of the ballast under repeated train passage. These unsupported track elements are often termed as hanging sleepers and they can lead to undesirable effects due to increased dynamic response of the train-track system, especially when the speed of the train is high. In this paper, we present a computation scheme in conjunction with the moving element method for the analysis of high-speed train-track dynamics accounting for hanging sleepers. The proposed computational scheme will be first verified by comparison with available analytical results. The dynamic response of a high-speed train traveling on a ballasted track considering unsupported sleepers is next investigated. Various factors affecting the response of the high-speed rail system including the speed of the train, the number of hanging sleepers and the pattern of the hanging sleepers will be examined and discussed.

Probabilistic Analysis of Flying Ballast on High-Speed Rail Lines

2017 ◽  
Author(s):  
Jieyi Deng ◽  
Guoqing Jing ◽  
Xiang Liu
Keyword(s):  
Risk Factors ◽  
High Speed ◽  
Safety Concern ◽  
Rolling Stock ◽  
Probabilistic Assessment ◽  
High Speed Train ◽  
Modeling Framework ◽  
High Speed Rail ◽  
Rail Systems ◽  
Ballasted Track

Safety is a top priority for the development of worldwide high-speed rail systems. Ballast flying is a particular safety concern when a high-speed train is traveling above a certain speed on the ballasted track. Displaced ballast particles from the track may cause damages to rolling stock, as well as the track infrastructure and wayside structures close to the sides of way. The objective of this research is to develop a probabilistic modeling framework to estimate the probability of ballast flight on specific segments or routes, accounting for several principal risk factors. Based on the probabilistic assessment, we propose a methodology to quantify the probability of flying ballast under certain scenarios. The methodology can be further developed, ultimately enabling a normative risk assessment for flying ballast risk management.

scholarly journals SOCIAL EXCLUSION AND HIGH SPEED RAIL: THE CASE STUDY OF SPAIN

2016 ◽  
Author(s):  
Francesca Pagliara ◽  
Fabrizio Menicocci ◽  
Jose Manuel Vassallo ◽  
Juan Gomez
Keyword(s):  
Social Exclusion ◽  
High Speed ◽  
Revealed Preference ◽  
Transport Systems ◽  
Long Distance ◽  
High Speed Rail ◽  
Socioeconomic Characteristics ◽  
Rail System ◽  
Rail Systems

Very few contributions in the literature have dealt with the issue of social exclusion related to High Speed Rail systems. The objective of this manuscript is to understand what are the factors excluding users from choosing High Speed Rail services considering as case study Spain. For this purpose, a Revealed Preference survey was employed in November and December 2015. A questionnaire was submitted to users of the Spanish transport systems travelling for long distance-journeys. The aim was that of investigating their perception of High Speed Rail system and the factors inhibiting passengers or excluding them from its use. Data about their socioeconomic characteristics were collected as well. The main result of the survey has been that a relationship between social exclusion and High Speed Rail in Spain is present, especially in terms of geographical exclusion.DOI: http://dx.doi.org/10.4995/CIT2016.2016.3100

ANALYSIS OF HIGH-SPEED RAIL ACCOUNTING FOR JUMPING WHEEL PHENOMENON

2014 ◽  
Vol 11 (03) ◽  
pp. 1343007 ◽  
Author(s):  
KOK KENG ANG ◽  
JIAN DAI ◽  
MINH THI TRAN ◽  
VAN HAI LUONG
Keyword(s):  
High Speed ◽  
Computational Study ◽  
Dynamic Responses ◽  
Contact Model ◽  
High Speed Train ◽  
Train Track ◽  
Hertz Contact ◽  
High Speed Rail ◽  
Track System ◽  
Hertz Contact Model

In this paper, a computational study using the moving element method (MEM) was carried out to investigate the dynamic response of a high-speed train–track system. Results obtained using Hertz contact model and linearized Hertz contact model are compared and discussed. The dynamic responses of a train travelling across a uniform foundation and a transition region are also investigated. Parametric study is performed to understand the effect of various factors on the occurrence and patterns of the jumping wheel phenomenon such as the variation of foundation stiffness, travelling speed of the train and the severity of railhead roughness.

Tribological and dynamical analysis of a brake pad with multiple blocks for a high-speed train

2019 ◽  
Vol 234 (11) ◽  
pp. 1771-1788
Author(s):  
YK Wu ◽  
JL Mo ◽  
B Tang ◽  
JW Xu ◽  
B Huang ◽  
...  
Keyword(s):  
High Speed ◽  
Wear Behavior ◽  
Dynamical Analysis ◽  
Brake Disc ◽  
Brake Pad ◽  
High Speed Train ◽  
Brake Squeal ◽  
Element Analysis ◽  
Single Block ◽  
Middle Ring

In this research, the tribological and dynamical characteristics of a brake pad with multiple blocks are investigated using experimental and numerical methods. A dynamometer with a multiblock brake pad configuration on a brake disc is developed and a series of drag-type tests are conducted to study the brake squeal and wear behavior of a high-speed train brake system. Finite element analysis is performed to derive physical explanations for the observed experimental phenomena. The experimental and numerical results show that the rotational speed and braking force have important influences on the brake squeal; the trends of the multiblock and single-block systems are different. In the multiblock brake pad, the different blocks exhibit significantly different magnitudes of contact stresses and vibration accelerations. The blocks located in the inner and outer rings have higher vibration acceleration amplitudes and stronger vibration energies than the blocks located in the middle ring.

scholarly journals A Review of Different Aspects of Applying Asphalt and Bituminous Mixes under a Railway Track

Materials ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 169
Author(s):  
Kazem Jadidi ◽  
Morteza Esmaeili ◽  
Mehdi Kalantari ◽  
Mehdi Khalili ◽  
Moses Karakouzian
Keyword(s):  
High Speed ◽  
Review Paper ◽  
Railway Track ◽  
High Speed Train ◽  
Slab Track ◽  
Bituminous Mixtures ◽  
Railway Tracks ◽  
Potential Applications ◽  
Heavy Loads ◽  
Design And Construction

Asphalt is a common material that is used extensively for roadways. Furthermore, bituminous mixes have been used in railways, both as asphalt and as mortar. Different agencies and research institutes have investigated and suggested various applications. These studies indicate the benefits of bituminous material under railways, such as improving a substructure’s stiffness and bearing capacity; enhancing its dynamic characteristics and response, especially under high-speed train loads; waterproofing the subgrade; protecting the top layers against fine contamination. These potential applications can improve the overall track structure performance and lead to minimizing settlement under heavy loads. They can also guarantee an appropriate response under high-speed loads, especially in comparison to a rigid slab track. This review paper documents the literature related to the utilization of asphalt and bituminous mixes in railway tracks. This paper presents a critical review of the research in the application of asphalt and bituminous mixes in railway tracks. Additionally, this paper reviews the design and construction recommendations and procedures for asphalt and bituminous mixes in railway tracks as practiced in different countries. This paper also provides case studies of projects where asphalt and bituminous mixes have been utilized in railway tracks. It is anticipated that this review paper will facilitate (1) the exchange of ideas and innovations in the area of the design and construction of railway tracks and (2) the development of unified standards for the design and construction of railway tracks with asphalt and bituminous mixtures.

Research on the Effects of Welding Sequence on Welding Residual Stress of High-Speed Train Based on SYSWELD

2011 ◽  
Vol 399-401 ◽  
pp. 1806-1811
Author(s):  
Yong Hong Chen ◽  
Peng Chen ◽  
Ai Qin Tian
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
High Speed ◽  
Element Model ◽  
Welding Residual Stress ◽  
High Speed Train ◽  
Distribution Law ◽  
Element Analysis ◽  
Welding Sequence ◽  
Maximum Residual Stress

The finite element model of the roof of aluminum high-speed train was established, double ellipsoid heat source was employed, and heat elastic-plastic theory was used to simulate welding residual stress of the component under different welding sequence based on the finite element analysis software SYSWELD. The distribution law of welding residual stress was obtained. And the effects of the welding sequence on the value and distribution of residual stress was analyzed. The numerical results showed that the simulation data agree well with experimental test data. The maximum residual stress appears in the weld seam and nearby. The residual stress value decreases far away from the welding center. Welding sequence has a significant impact on the final welding residual stress when welding the roof of aluminum body. The side whose residual stress needs to be controlled should be welded first.

scholarly journals A study on small-world characteristics of Chinaäó»s high-speed railway networks

2016 ◽  
Author(s):  
Xin Yuan ◽  
Guo Liu ◽  
Kun Hui Ye
Keyword(s):  
High Speed ◽  
Small World ◽  
Clustering Coefficient ◽  
High Speed Rail ◽  
Attribute Data ◽  
The Social ◽  
The Difference ◽  
Global And Local ◽  
The Relationship ◽  
Space Method

The small-world model provides a useful perspective and method to study the topological structure and intrinsic characteristics of high-speed rail networks (HRNs). In this paper, the P-space method is used to examine global and local HRNs in China, meanwhile the adjacency matrix is developed, then the social network analysis and visualization tool UCINET is used to calculate the spatial and attribute data of HRNs at national and local levels in China. The small-world characteristics of whole HRNs are discussed, three networks which have different properties are determined, and a comparative analysis of the small-world effect is detected. Then, the relationship between the construction of high-speed rail and regional development of China is analysed. The results show that: 1) China's HRNs have small average path length ( L ) and large clustering coefficient (C ), representing a typical small-world network; 2) Local HRNs have a certain correlation with economic development. The reasons for the difference of HRNs with respect to characteristics among regions are eventually discussed.

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