A 3D Dynamic Train-track Interaction Model to Study Track Performance Under Trains Running at Critical Speed PDF Download
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Author: Yin Gao
Publisher:
ISBN:
Category :
Languages : en
Pages : 94
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Book Description
Author: Yin Gao
Publisher:
ISBN:
Category :
Languages : en
Pages : 94
Get Book Here
Book Description
Author: Yin Gao
Publisher:
ISBN:
Category :
Languages : en
Pages :
Get Book Here
Book Description
Railroad transportation, especially high-speed passenger rail, has been developing at sensational speed, creating the needs to evaluate the track safety and predict the potential hazards for railroad operation. As train speed increases, the responses of the train and track substructure present larger dynamic behavior, which raises problems in passenger comfort, operational safety and track structures. With the boom of modeling and computing techniques, numerical simulation becomes a more feasible, safe and effective tool to identify the problems in railroad engineering. In this dissertation, a self-developed three-dimensional train-track interaction model is formulated, validated and implemented to predict the potential risks and explore the mechanisms of rail track problems.The developed 3D dynamic track-subgrade interaction model includes a train model, 2D discrete support track model and 3D computation-efficient finite element (FE) soil subgrade model. The rail beam is modeled as a Euler-Bernoulli Beam. The 2D track model discretizes the tie and ballast as rigid bodies with designated spacing. The discretely supported system enables the track model to take the track longitudinal variations into consideration. The subgrade model is simulated by finite element method with quadrilateral elements. Since the subgrade of a tangent track is considered as homogeneous in the moving direction, the formulation of the subgrade is derived in a computing-efficient way by expanding the longitudinal direction in the frequency domain. Therefore, the computing time is significantly reduced. The entire model is a self-developed program, which is coded in MATLAB.Field data collected in x, y, z directions were used to validate the accuracy of the dynamic track-subgrade interaction model. Testing sites were located on Amtraks highest speed (240 km/hr) line near Kingston, Rhode Island, on the Northeast Corridor in United States. Track deflections and the ground wave motion measured in the field were compared with those predicted by the 3D dynamic track-subgrade interaction model.Some applications of the 3D dynamic track-subgrade interaction model are included in this dissertation, as follow.Critical speed study: Amtrak requires more frequent maintenance for the North East Corridor (NEC) at Kingston, Rhode Island (known as the Great Swamp area). It was suspected that a condition, known as critical speed, might exist at this particular location. The conventional definition of critical speed of a railroad system is the speed at which vibrations propagate within the track structure and subgrade at a speed close to the Rayleigh wave velocity of the subgrade soil. As trains travel at speeds approaching the critical speed, all track components are expected to present significantly increased vibrations. However, no historical data indicated such dramatic increment in track responses at the Great Swamp area. Therefore, the 3D dynamic track-subgrade interaction model was used to evaluate the track performance under the current range of operation speeds and predicted the track responses at train speeds higher than the track speed limits. According to the results and analysis, the critical speed effect at the Kingston site could not be comprehensively explained by the conventional definition of the critical speed. Therefore, a two-level explanation is used to address the phenomenon at this site.Hanging tie detection: the hanging tie condition is that in which voids have developed beneath the ties, causing tie-ballast gaps. The existence of the tie-ballast gaps can result in larger peak accelerations at the unsupported or poorly supported ties. This will increase the dynamic contact force between tie and ballast, and then further deteriorate the track structure. However, currently the railroad industry has difficulties in identifying hanging ties in the field since the problem is buried beneath the track. Therefore, the previously developed model was used to propose a fast, nondestructive screening method to identify the hanging tie problem. The method utilized a dynamic track model to characterize the track's Moving Deflection Spectrum (MDS) under different tie-supporting scenarios. The MDSs of tracks without a hanging tie problem have a clear peak at the Tie Spacing Frequency. However, tracks have a hanging tie problem if the MDSs present a significantly increased peak in the low frequency region (the frequency below the Tie Spacing Frequency). The modeling results were further validated by the field investigations conducted on three metro lines in Boston and St. Louis. Accelerometers were mounted on a high-rail vehicle to measure the acceleration of the moving wheels. The MDSs were then calculated to predict the potential locations of hanging ties. The locations of hanging ties predicted by the model matched the field observations. Tie movements characterization: modeling techniques were used to predict the movements of railroad ties under moving train passage in this study. The ballast and other track substructures performances are largely dependent on the tie-ballast contact. Therefore, characterizing the tie movements could potentially bring new concepts to the conventional laboratory tests and practical maintenance for railroad engineering. In order to obtain the tie movements numerically, two steps were made by combining a commercial vehicle dynamics model with a track model established in the commercial software ABAQUS. The modeling results showed that the motion of ties not only contains translational movements, but also rotations. The field tests to validate this finding were conducted on an Amtrak high-speed passenger line and a freight railroad short line. The measuring units were mounted on ties to record the accelerations and the changes in Euler angles of the ties in three orthogonal directions. The measurements of tie displacements and rotations in the field tests had good agreement with the modeling results. Moreover, field tests indicated that the tie-ballast gaps may cause higher accelerations and angular velocities of ties. Then the effect of tie rotation was investigated by discrete element modeling. The modeling results showed that the acceleration of individual ballast particles and ballast contact forces could have significant increase when the tie rotation is considered.Overall, the 3D train-track interaction model is capable of simulating the railroad tracks of various conditions by integrating the discrete supports and 3D subgrade model. The model can be a reliable and effective tool for railroad industry. The versatility of the model makes it have great potential for future research and references.
Author: Kannan Govindan
Publisher: Springer Nature
ISBN: 9811627940
Category : Technology & Engineering
Languages : en
Pages : 1422
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Book Description
This book presents select papers from the International Conference on Energy, Material Sciences and Mechanical Engineering (EMSME) - 2020. The book covers the three core areas of energy, material sciences and mechanical engineering. The topics covered include non-conventional energy resources, energy harvesting, polymers, composites, 2D materials, systems engineering, materials engineering, micro-machining, renewable energy, industrial engineering and additive manufacturing. This book will be useful to researchers and professionals working in the areas of mechanical and industrial engineering, materials applications, and energy technology.
Author: João Pombo
Publisher: Springer
ISBN: 3319616277
Category : Science
Languages : en
Pages : 177
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Book Description
This volume brings together scientific experts in different areas that contribute to the Railway Track & Transportation Engineering challenges, evaluate the State-of-the-Art, identify the shortcomings and opportunities for research and promote the interaction with the industry. In particular, scientific topics that are addressed in this volume include railway ballasted track degradation/settlement problems and stabilization/reinforcement technologies, switches and crossings and related derailments causes, train-induced vibrations and mitigation measures, operations, management and performance of ground transportation, and traffic congestion and safety procedures. This volume is part of the proceedings of the 1st GeoMEast International Congress and Exhibition on Sustainable Civil Infrastructures, Egypt 2017.
Author: Weihua Zhang
Publisher: Academic Press
ISBN: 0128134011
Category : Technology & Engineering
Languages : en
Pages : 612
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Book Description
Dynamics of Coupled Systems in High-Speed Railways: Theory and Practice presents the relationship between various coupled systems that can affect train operation, including interaction between track and train, the pantograph-catenary system and train, power supply system and train, and airflow and train, with respect to the structure and characteristics of high-speed railway. The overall simulation optimization and control are achieved based on an analysis of the dynamics generated by coupled systems in high-speed trains, with a theoretical framework for the dynamics presented in the book. Presents the first book available on the dynamics of coupled systems in high-speed trains Provides a systematic view of high-speed vehicle dynamics, covering the issues that are especially concerned for high speed operations, such as high-speed pantograph and catenary, aerodynamic characteristics and running stability of high-speed trains Covers the optimization of dynamic performance, the design of parameters, the simulation of high-speed train service processes, and the identification of high-speed train state and condition assessment
Author: Xiaoyan Lei
Publisher: Springer
ISBN: 9811020396
Category : Technology & Engineering
Languages : en
Pages : 431
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Book Description
This book systematically summarizes the latest research findings on high-speed railway track dynamics, made by the author and his research team over the past decade. It explores cutting-edge issues concerning the basic theory of high-speed railways, covering the dynamic theories, models, algorithms and engineering applications of the high-speed train and track coupling system. Presenting original concepts, systematic theories and advanced algorithms, the book places great emphasis on the precision and completeness of its content. The chapters are interrelated yet largely self-contained, allowing readers to either read through the book as a whole or focus on specific topics. It also combines theories with practice to effectively introduce readers to the latest research findings and developments in high-speed railway track dynamics. It offers a valuable resource for researchers, postgraduates and engineers in the fields of civil engineering, transportation, highway & railway engineering.
Author: Karl Popp
Publisher: Springer Science & Business Media
ISBN: 3540454764
Category : Technology & Engineering
Languages : en
Pages : 503
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Book Description
During the last decades completely new technologies for high speed railway vehicles have been developed. The primary goals have been to increase traction, axle load, and travelling speed, and to guarantee the safety of the passengers. However, new developments have revealed new limitations: settlement and destruction of the ballast and the subgrade lead to deterioration of the track; irregular wear of the wheels causes an increase in overall load and deterioration in passenger comfort; and damage of the running surfaces of the rail and the wheel is becoming more frequent. These problems have been investigated in the Priority Programme SPP 1015 supported by the Deutsche Forschungsgemeinschaft (DFG), with the goal of better understanding of the dynamic interaction of vehicle and track, and the long-term behavior of the components of the system. The book contains the scientific results of the programme as presented at the concluding colloquium held at University of Stuttgart, Germany, 2002.
Author: Sirong Yi
Publisher: Academic Press
ISBN: 0128129344
Category : Technology & Engineering
Languages : en
Pages : 326
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Book Description
Dynamic Analysis of High-Speed Railway Alignment: Theory and Practice elaborates on the dynamic analysis theory and method on spatial alignment parameters of high-speed railways, revealing the interaction mechanism between vehicle-track dynamic performance and track parameters of high-speed railways. It ascertains the influence rules of track structure and track geometry on vehicle-track dynamic performance, establishes the relationship models between vehicle-track dynamic performance and curve dynamic characteristic parameters, and defines the calculation relationship between lateral acceleration of car body on curves and track parameters. This book can be used as a reference book for scientific researchers, engineering technicians and management engaged in railway engineering, and will be very helpful for railway technicians who want to learn more about route planning, design, and construction and maintenance technologies of high-speed railways. Presents the dynamic effects between the running speed of high-speed trains on curves and spatial curve technical parameters Provides dynamic analysis, theory and methods on curve parameters of high-speed railways and improves the calculation theory on spatial alignment of high-speed railways Covers minimum curve radius, transition curve length, minimum radius of vertical curve, steepest slope, minimum slope length and length of intermediate straight line
Author: Wanming Zhai
Publisher: Springer Nature
ISBN: 9813292830
Category : Technology & Engineering
Languages : en
Pages : 417
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Book Description
This book systematically presents the theory, numerical implementation, field experiments and practical engineering applications of the ‘Vehicle–Track Coupled Dynamics’. Representing a radical departure from classic vehicle system dynamics and track dynamics, the vehicle–track coupled dynamics theory considers the vehicle and track as one interactive and integrated system coupled through wheel–rail interaction. This new theory enables a more comprehensive and accurate solution to the train–track dynamic interaction problem which is a fundamental and important research topic in railway transportation system, especially for the rapidly developed high-speed and heavy-haul railways. It has been widely applied in practical railway engineering. Dr. Wanming Zhai is a Chair Professor of Railway Engineering at Southwest Jiaotong University, where he is also chairman of the Academic Committee and Director of the Train and Track Research Institute. He is a member of the Chinese Academy of Sciences and one of the leading scientists in railway system dynamics. Professor Zhai is Editor-in-Chief of both the International Journal of Rail Transportation, published by Taylor & Francis Group, and the Journal of Modern Transportation, published by Springer. In addition, he is a trustee of the International Association for Vehicle System Dynamics, Vice President of the Chinese Society of Theoretical and Applied Mechanics, and Vice President of the Chinese Society for Vibration Engineering. /div
Author: Alexey Vostrukhov
Publisher: LAP Lambert Academic Publishing
ISBN: 9783846599563
Category :
Languages : en
Pages : 200
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Book Description
The research presented in this book was carried out in the framework of doctorate studies at Nizhny Novgorod State University (1998-2001) and at Faculty of Civil Engineering and Geosciences of Delft University of Technology (2001-2002) under supervision of Prof. G.A.Utkine, Prof. ir. A.C.W.M. Vrouwenvelder, and Prof. A.V.Metrikine, to whom I would like to express words of an unlimited gratitude, especially to Andrei Metrikine for his enthusiasm, attention, care, patience and specific sense of humor.
