Middle-Frequency Wheel-Rail Contact Forces of High Speed Trains and the Validation of a Model with Field Measurements

2012 ◽  
Author(s):  
X.C. Jin
Keyword(s):  
High Speed ◽  
Field Measurements ◽  
Contact Forces ◽  
High Speed Trains

A Nonlinear Rail Vehicle Dynamics Computer Program SAMS/Rail: Part 1—Theory and Formulations

2009 ◽  
Author(s):  
Khaled E. Zaazaa ◽  
Brian Whitten ◽  
Brian Marquis ◽  
Erik Curtis ◽  
Magdy El-Sibaie ◽  
...  
Keyword(s):  
High Speed ◽  
Dynamic Performance ◽  
Three Dimensional ◽  
Contact Element ◽  
Contact Forces ◽  
Simulation Code ◽  
Vehicle Performance ◽  
Normal Contact ◽  
Advantages And Disadvantages ◽  
High Speed Trains

Accurate prediction of railroad vehicle performance requires detailed formulations of wheel-rail contact models. In the past, most dynamic simulation tools used an offline wheel-rail contact element based on look-up tables that are used by the main simulation solver. Nowadays, the use of an online nonlinear three-dimensional wheel-rail contact element is necessary in order to accurately predict the dynamic performance of high speed trains. Recently, the Federal Railroad Administration, Office of Research and Development has sponsored a project to develop a general multibody simulation code that uses an online nonlinear three-dimensional wheel-rail contact element to predict the contact forces between wheel and rail. In this paper, several nonlinear wheel-rail contact formulations are presented, each using the online three-dimensional approach. The methods presented are divided into two contact approaches. In the first Constraint Approach, the wheel is assumed to remain in contact with the rail. In this approach, the normal contact forces are determined by using the technique of Lagrange multipliers. In the second Elastic Approach, wheel/rail separation and penetration are allowed, and the normal contact forces are determined by using Hertz’s Theory. The advantages and disadvantages of each method are presented in this paper. In addition, this paper discusses future developments and improvements for the multibody system code. Some of these improvements are currently being implemented by the University of Illinois at Chicago (UIC). In the accompanying “Part 2” and “Part 3” to this paper, numerical examples are presented in order to demonstrate the results obtained from this research.

scholarly journals Field measurements of aerodynamic pressures in tunnels induced by high speed trains

2012 ◽  
Vol 100 (1) ◽  
pp. 19-29 ◽  
Author(s):  
Yung-Yen Ko ◽  
Cheng-Hsing Chen ◽  
Ing-Tsang Hoe ◽  
Shin-Tsyr Wang
Keyword(s):  
High Speed ◽  
Field Measurements ◽  
High Speed Trains

scholarly journals Wind Load Characteristics of Wind Barriers Induced by High-Speed Trains Based on Field Measurements

2019 ◽  
Vol 9 (22) ◽  
pp. 4865 ◽  
Author(s):  
Zou ◽  
Fu ◽  
He ◽  
Cai ◽  
Zhou ◽  
...  
Keyword(s):  
High Speed ◽  
Field Measurements ◽  
Wind Pressure ◽  
Wind Loads ◽  
Head Wave ◽  
Pulse Excitation ◽  
Multi Resolution Analysis ◽  
High Speed Trains ◽  
Resolution Analysis ◽  
Wind Barrier

This paper focuses on field measurements and analyses of train-generated wind loads on wind barriers (3.0 m height and porosity 0%) with respect to different running speeds of the CRH380A EMU vehicle. Multi-resolution analysis was conducted to identify the pressure distribution in different frequency bands. Results showed that the wind pressure on the wind barrier caused by train-induced wind had two significant impacts with opposite directions, which were the “head wave” and “tail wave”. The peak wind pressure on the wind barrier was approximately proportional to the square of the speed of the train, and the peak wind pressure decreased rapidly along the wind barrier height from the bottom of the wind barrier. The maximum wind pressure occurred at the rail surface height. Furthermore, results of the multi-resolution analysis illustrated that the energy of the frequency band from 0 to 2.44 Hz accounted for 94% of the total energy. This indicated that the low-frequency range component of the wind pressure dominated the design of the wind barrier. The frequency of pulse excitation of train-induced wind loads may overlap with the natural frequency of barriers, and may lead to fatigue failure due to cyclic loads generated by the repeated passage of high-speed trains. In addition, the speed of the train had a negligible effect on the energy distribution of the wind pressure in the frequency domain, while the extreme pressure increased slightly with the increase of the speed of the train.

Realizing a Self-powered Real-time Monitoring System on High-speed Trains

2021 ◽  
Vol 263 (6) ◽  
pp. 434-441
Author(s):  
S.K. Lai ◽  
C. Wang ◽  
L.H. Zhang ◽  
Y.Q. Ni
Keyword(s):  
Real Time ◽  
High Speed ◽  
Energy Harvester ◽  
Contact Forces ◽  
Dynamic Responses ◽  
Real Time Monitoring ◽  
Harvesting Technique ◽  
High Speed Trains ◽  
Noise Data ◽  
Self Powered

The development of the worldwide high-speed rail network is expanding at a rapid pace, imposing great challenges on the operation safety. Recent advances in wireless communications and information technology can integrate the Internet of Things and cloud computing to form a real-time monitoring platform of high-speed trains. To realize this system, a sustainable power source is indispensable. In this case, an ideal solution is to deploy a vibration-based energy harvester instead of batteries for the electrical supply of wireless sensors/devices, as vibrations induced by rail/wheel contact forces and vehicle dynamics are an abundant energy source. To address this challenge, a multi-stable, broadband and tri-hybrid energy harvesting technique was recently proposed, which can work well under low-frequency, low-amplitude, and time-varying ambient sources. In this work, we will introduce our idea, following the recently proposed energy harvester and the dynamic responses of a train vehicle, to design a self-sustained sensing system on trains. Supported by this self-powered system, accelerometers and microphones deployed on an in-service train (in axle boxes/bogie frames) can measure vibration and noise data directly. The correlation of the vibration and noise data can then be analyzed simultaneously to identify the dynamic behavior (e.g., wheel defects) of a moving train.

Field measurements of the evolution of wheel wear and vehicle dynamics for high-speed trains

2017 ◽  
Vol 56 (8) ◽  
pp. 1187-1206 ◽  
Author(s):  
Huailong Shi ◽  
Jianbin Wang ◽  
Pingbo Wu ◽  
Chunyuan Song ◽  
Wanxiu Teng
Keyword(s):  
Vehicle Dynamics ◽  
High Speed ◽  
Field Measurements ◽  
Wheel Wear ◽  
High Speed Trains

Battery Self-Traction System for High-Speed Trains

2020 ◽  
Vol 140 (5) ◽  
pp. 349-355
Author(s):  
Hirokazu Kato ◽  
Kenji Sato
Keyword(s):  
High Speed ◽  
High Speed Trains ◽  
Traction System

Modeling of Tread Block Contact Mechanics Using Linear Viscoelastic Theory3

2008 ◽  
Vol 36 (3) ◽  
pp. 211-226 ◽  
Author(s):  
F. Liu ◽  
M. P. F. Sutcliffe ◽  
W. R. Graham
Keyword(s):  
High Speed ◽  
Slip Rate ◽  
Material Model ◽  
Contact Forces ◽  
Block Modeling ◽  
Rate Dependent ◽  
Linear Viscoelastic Material ◽  
Linear Viscoelastic ◽  
The Impact ◽  
Good Agreement

Abstract In an effort to understand the dynamic hub forces on road vehicles, an advanced free-rolling tire-model is being developed in which the tread blocks and tire belt are modeled separately. This paper presents the interim results for the tread block modeling. The finite element code ABAQUS/Explicit is used to predict the contact forces on the tread blocks based on a linear viscoelastic material model. Special attention is paid to investigating the forces on the tread blocks during the impact and release motions. A pressure and slip-rate-dependent frictional law is applied in the analysis. A simplified numerical model is also proposed where the tread blocks are discretized into linear viscoelastic spring elements. The results from both models are validated via experiments in a high-speed rolling test rig and found to be in good agreement.

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