DOCSLIB.ORG

Field and Analytical Investigation of a 3D Dynamic Train-Track Interaction Model at Critical Speeds

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Field and Analytical Investigation of a 3D Dynamic Train-Track Interaction Model at Critical Speeds The Pennsylvania State University The Graduate School Department of Civil and Environmental Engineering FIELD AND ANALYTICAL INVESTIGATION OF A 3D DYNAMIC TRAIN-TRACK INTERACTION MODEL AT CRITICAL SPEEDS A Dissertation in Civil Engineering by Yin Gao 2016 Yin Gao Submitted in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy August 2016 ii The dissertation of Yin Gao was reviewed and approved* by the following: Hai Huang Associate Professor of Rail Transportation Engineering Dissertation Adviser Co-chair of Committee Shelley Marie Stoffels Professor of Civil Engineering Co-chair of Committee Tong Qiu Associate Professor of Civil and Environmental Engineering Jamal Rostami Associate Professor of Energy and Mineral Engineering Patrick Fox Professor of Civil and Environmental Engineering Department Head of Civil and Environmental Engineering *Signatures are on file in the Graduate School iii ABSTRACT 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 Amtrak’s 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 iv 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 v 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. vi TABLE OF CONTENTS ABSTRACT ............................................................................................................................. iii TABLE OF CONTENTS ......................................................................................................... vi LIST OF FIGURES ................................................................................................................. x LIST OF TABLES ................................................................................................................... xv ACKNOWLEDGEMENTS ..................................................................................................... xvi Chapter 1 RESEARCH INTRODUCTION, MOTIVATION, OBJECTIVES AND METHODOLOGY ........................................................................................................... 1 Introduction and Motivation ............................................................................................ 1 Objectives......................................................................................................................... 2 Scope and Methodology ................................................................................................... 3 Expected Contribution ..................................................................................................... 4 Engineering Significance ................................................................................................. 4 Chapter 2 BACKGROUND AND LITERATURE REVIEW ................................................. 6 A Brief Introduction to Railway Engineering .................................................................. 6 Railway Vehicle ............................................................................................................... 11 Vehicle Modeling ............................................................................................................
Load more

Recommended publications
  • Calculated Estimation of Railway Wheels Equivalent Conicity Influence on Critical Speed of Railway Passenger Car
    MATEC Web of Conferences 157, 03006 (2018) https://doi.org/10.1051/matecconf/201815703006 MMS 2017 Calculated estimation of railway wheels equivalent conicity influence on critical speed of railway passenger car Juraj Gerlici1,*, Rostyslav Domin2, Ganna Cherniak2, Tomáš Lack1 1University of Žilina, Faculty of Mechanical Engineering, Department of Transport and Handling Machines, 010 26 Žilina, Slovak Republic 2Volodymyr Dahl East Ukrainian National University, Department of Rail Transport, 93400 Sewerodonetsk, Ukraine Abstract. The article presents the results of determining the equivalent conicity characterizing the geometric interaction of wheels and rails on 1520 mm track. The cases of interactions of rails and wheelsets, wheels of which have different profiles, are considered. The computer model of the motion speed of the passenger car is developed. According to the results of computer simulation, critical speeds for the bogie moving through the tracks of indented gauge are received. Based on the results of the simulation analysis, the significant dependence of the value of the equivalent conicity on the critical speed is confirmed. The necessity of considering the limit values of equivalent conicity in tests of high-speed rolling stock is emphasized. Keywords: railway wheels, equivalent conicity, critical speed, passenger vehicle 1 Introduction The increase of speed of passenger trains up to 160-200 km/h brings new technological level on the Ukrainian railways. Cars of high-speed trains must fully comply with international requirements, both in the level of comfort, and in terms of safety. In this regard, the task of ensuring the stability of motion of the high-speed rolling stock must be resolved as a matter of priority.
    [Show full text]
  • 1976 Technical Documentation Locomotive Truck Hunting M.Pdf
    TECHNICAL DOCUMENTATION LOCOMOTIVE TRUCK HUNTING MODEL V. K. Garg OHO G. C. Martin P. W. Hartmann J. G. Tolomei mnnnn irnational Government-Industry 04 - Locomotives ch Program on Track Train Dynamics R-219 TE C H N IC A L DOCUMENTATION rnn nnn LOCOMOTIVE TRUCK HUNTING MODEL V. K. Garg G. C. Martin P. W. Hartmann a a J. G. Tolomei dD 11 TT|[inr i3^1 i i H§ic§ An International Government-Industry Research Program on Track Train Dynamics Chairman L. A. Peterson J. L. Cann Director Vice President Office of Rail Safety Research Steering Operation and Maintenance Federal Railroad Administration Canadian National Railways G. E. Reed Vice Chairman Director Committee W. J. Harris, Jr. Railroad Sales Vice President AMCAR Division Research and Test Department ACF Industries Association of American Railroads D. V. Sartore or the E. F. Lind Chief Engineer Design Project Director-Phase I Burlington Northern, Inc. Track Train Dynamics Southern Pacific Transportation Co. P. S. Settle Tack Tain President M. D. Armstrong Railway Maintenance Corporation Chairman Transportation Development Agency W. W. Simpson Dynamics Canadian Ministry of Transport Vice President Engineering W. S. Autrey Southern Railway System Chief Engineer Atchison, Topeka & Santa Fe Railway Co. W. S. Smith Vice President and M. W. Beilis Director of Transportation Manager General Mills, Inc. Locomotive Engineering General Electric Company J. B. Stauffer Director M. Ephraim Transportation Test Center Chief Engineer Federal Railroad Administration Electro Motive Division General Motors Corporation R. D. Spence (Chairman) J. G. German President Vice President ConRail Engineering Missouri Pacific Co. L. S. Crane (Chairman) President and Chief W.
    [Show full text]
  • For Precise Evaluation of Wheel-Rail Contact Mechanics and Dynamics [Doctoral Thesis]", in Mechanical Engineering
    Accurate Wheel-rail Dynamic Measurement using a Scaled Roller Rig Karan Kothari Thesis submitted to the faculty of the Virginia Polytechnic Institute and State University in partial fulfillment of the requirements for the degree of Masters of Science In Mechanical Engineering Mehdi Ahmadian, Chair Steve C Southward Reza Mirzaeifar June 19, 2018 Blacksburg, VA Keywords: scaled roller rig, dynamic measurements, wheel-rail contact, traction forces, angle of attack, third-body layer, wheel wear Accurate Wheel-rail Dynamic Measurement using a Scaled Roller Rig Karan Kothari Abstract (academic) The primary purpose of this study is to perform accurate dynamic measurements on a scaled roller rig designed and constructed by Virginia Tech and the Federal Railroad Administration (VT-FRA Roller Rig). The study also aims at determining the effect of naturally generated third-body layer deposits (because of the wear of the wheel and/or roller) on creep or traction forces. The wheel- rail contact forces, also referred to as traction forces, are critical for all aspects of rail dynamics. These forces are quite complex and they have been the subject of several decades of research, both in experiments and modeling. The primary intent of the VT-FRA Roller Rig is to provide an experimental environment for more accurate testing and evaluation of some of the models currently in existence, as well as evaluate new hypothesis and theories that cannot be verified on other roller rigs available worldwide. The Rig consists of a wheel and roller in a vertical configuration that allows for closely replicating the boundary conditions of railroad wheel-rail contact via actively controlling all the wheel-rail interface degrees of freedom: angle of attack, cant angle, normal load and lateral displacement, including flanging.
    [Show full text]
  • The Effect of Crosswinds on Ride Comfort in High Speed Trains Running on Curves Dyna, Vol
    Dyna ISSN: 0012-7353 [email protected] Universidad Nacional de Colombia Colombia Aizpun-Navarro, Miguel; Sesma-Gotor, Ignacio The effect of crosswinds on ride comfort in high speed trains running on curves Dyna, vol. 82, núm. 194, diciembre, 2015, pp. 46-51 Universidad Nacional de Colombia Medellín, Colombia Available in: http://www.redalyc.org/articulo.oa?id=49643211006 How to cite Complete issue Scientific Information System More information about this article Network of Scientific Journals from Latin America, the Caribbean, Spain and Portugal Journal's homepage in redalyc.org Non-profit academic project, developed under the open access initiative The effect of crosswinds on ride comfort in high speed trains running on curves Miguel Aizpun-Navarro a & Ignacio Sesma-Gotor b a Escuela de Ingeniería Mecánica, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile. [email protected] b Departamento de Mecánica Aplicada, CEIT, Donostia San Sebastián, España. [email protected] Received: July 25th, 2014. Received in revised form: March 15th, 2015. Accepted: November 8th, 2015 Abstract The effect of crosswinds on the risk of railway vehicles overturning has been a major issue ever since manufacturers began to produce lighter vehicles that run at high speeds. However, ride comfort can also be influenced by crosswinds, and this effect has not been thoroughly analyzed. This article describes the effect of crosswinds on ride comfort in high speed trains when running on curves and for several wind velocities under a Chinese hat wind scenario, which is the scenario recommended by the standard. Simulation results show that the combination of crosswinds and the added stiffness of the lateral bumpstop on the secondary suspension can become a significant source of instability, leading to flange-to-flange contact and greatly jeopardizing ride comfort.
    [Show full text]
  • Hunting Stability Analysis of Railway Systems Term Project in Vehicle Dynamics Course@IIT Hyderabad
    Hunting stability analysis of railway systems Term Project in Vehicle Dynamics Course@IIT Hyderabad Borrowed from – ‘Hunting By stability analysis of a Chetan S me15mtech11022 railway vehicle system using Anvesh Kumar me15mtech11020 a novel non-linear creep model’ by Yung Chang Saitheja V me15mtech11032 Cheng Course Instructor: Dr. Ashok Kumar Pandey What is hunting oscillation? • Wheels of ‘traction railway system’ have a cone angle. • At high speed , adhesion force is in-sufficient in maintaining stability and the wheels start to oscillate. • This oscillation about the mean position where it is ‘trying’ to find the equilibrium position is called hunting. • We pretty much know the obvious implications of these oscillation. Approach to hunting oscillation solution • Various models a. Linear Figure 1 b. Non-linear • A modified non-linear concept is propose by the author. • Why linear to non-linear? Figure 2 Cad Model of Locomotive Cad Model of suspension system Car Body Model It has three parts : 1. Wheel 2. Bogie/Truck 3. Car Figure 3 Governing equations of wheel-sets Figure 4 Governing equations of wheel-sets Equations for non-linear creep forces Governing equations of wheel-sets Equations for non-linear creep forces(Continued) Assumptions • α푖푗 = 1 (to convert non-linear to linear) • ϕ푤푖푗 = (λ푦푖푗)/a (roll angle of front and rear wheels) • ϕ푠푒 = 0 (super-elevation angle of curved track) • W=푊푒푥푡 (external load) Proposed linear model Proposed linear model(continued) Stability Analysis using Lyapunov • How to use it in this model? Note:
    [Show full text]
  • Critical Speed Analysis of Railcars and Wheelsets on Curved and Straight Track Joanna Charlotte Moody Bates College
    Bates College SCARAB Honors Theses Capstone Projects Spring 5-2014 Critical Speed Analysis of Railcars and Wheelsets on Curved and Straight Track Joanna Charlotte Moody Bates College Follow this and additional works at: http://scarab.bates.edu/honorstheses Recommended Citation Moody, Joanna Charlotte, "Critical Speed Analysis of Railcars and Wheelsets on Curved and Straight Track" (2014). Honors Theses. 107. http://scarab.bates.edu/honorstheses/107 This Open Access is brought to you for free and open access by the Capstone Projects at SCARAB. It has been accepted for inclusion in Honors Theses by an authorized administrator of SCARAB. For more information, please contact [email protected]. Critical Speed Analysis of Railcars and Wheelsets on Curved and Straight Track An Honors Thesis Presented to the Department of Physics and Astronomy Bates College in partial fulfillment of the requirements for the Degree of Bachelor of Science by Joanna Moody Lewiston, Maine April 1, 2014 Acknowledgments Ihavehadtoovercomemanystressfulobstaclesalongthewaytowardtheculminationof this thesis; however, I was fortunate enough not to have to tackle these obstacles alone. This thesis would not be all that it is had I not had the support of many people, including my professors, both within and outside the physics department, my friends, and my family. In particular, I would like to thank my thesis advisor, Nathan Lundblad, for allowing me to pursue my passion and for being willing to advise a thesis outside of his comfort zone. He has not only been an indispensable resource to me in composing this thesis, but has also served as a mentor for me since my first year at Bates.
    [Show full text]
  • Conventional Line Speed Increases and Development of Shinkansen Asahi Mochizuki
    Breakthrough in Japanese Railways 7 Conventional Line Speed Increases and Development of Shinkansen Asahi Mochizuki This article explains some technical developments in speed Increasing speeds on conventional lines increase until the opening of the shinkansen in 1964, centred In a nutshell, the history of railway technology is the history on lines belonging to JR companies (formerly Japanese of increased speeds and enhanced transport capacity. National Railways or JNR). Looking at the example of the Tokaido Line, Japan’s main trunk line, many modifications were constantly being made Increasing Speeds on Conventional Lines to shorten the travel time between Tokyo and Osaka. Even so, the maximum speed up to the 1950s was 95 km/h. Non-shinkansen lines (often including non-JR railways) in However, electrification toward the end of this era made Japan are commonly called conventional lines. Japan is a it possible to shorten journey times without increasing mountainous country, and most conventional lines were built maximum speed (Figure 1). to the narrow gauge of 1067 mm, but some private lines The limiting factors were the tractive power of steam and use standard gauge (1435 mm). When trying to increase the weak ground under the roadbed, which limited maximum operating speeds in the era of stream-hauled trains, narrow axle loads. For comparison, on the standard-gauge South gauge proved to have intrinsic disadvantages and the many Manchurian Railway, operating speed of 110 km/h was curves and grades in Japan’s mountainous areas also attained by express trains built in 1934 using Japanese hampered speed increase. technology. Some speed increase with electric locomotives Against this background, electric trains—especially was possible by electrification, but electrification was not electric multiple units (EMUs)—seems to offer the greatest popular for various reasons.
    [Show full text]
  • The Effect of Crosswinds on Ride Comfort in High Speed Trains Running on Curves
    The effect of crosswinds on ride comfort in high speed trains running on curves Miguel Aizpun-Navarro a & Ignacio Sesma-Gotor b a Escuela de Ingeniería Mecánica, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile. [email protected] b Departamento de Mecánica Aplicada, CEIT, Donostia San Sebastián, España. [email protected] Received: July 25th, 2014. Received in revised form: March 15th, 2015. Accepted: November 8th, 2015 Abstract The effect of crosswinds on the risk of railway vehicles overturning has been a major issue ever since manufacturers began to produce lighter vehicles that run at high speeds. However, ride comfort can also be influenced by crosswinds, and this effect has not been thoroughly analyzed. This article describes the effect of crosswinds on ride comfort in high speed trains when running on curves and for several wind velocities under a Chinese hat wind scenario, which is the scenario recommended by the standard. Simulation results show that the combination of crosswinds and the added stiffness of the lateral bumpstop on the secondary suspension can become a significant source of instability, leading to flange-to-flange contact and greatly jeopardizing ride comfort. Moreover, this comfort problem is an issue even when the wheel unloading ratio is well below the standard’s limits and vehicle safety can be guaranteed. Keywords: Rail vehicle models; crosswind stability; ride quality. Influencia del viento lateral en el confort de vehículos ferroviarios de alta velocidad circulando en curvas Resumen La influencia del viento lateral en el descarrilamiento de los vehículos ferroviarios es un factor crítico desde que se comenzaron a producir vehículos ligeros que circulan a altas velocidades.
    [Show full text]
  • Improving the Track Friendliness of a Four-Axle Railway Vehicle Using an Inertance-Integrated Lateral Primary Suspension
    Improving the Track Friendliness of a Four-Axle Railway Vehicle Using an Inertance-Integrated Lateral Primary Suspension T.D. Lewisa, Y. Lia∗, G.J. Tuckerb, J.Z. Jianga, Y. Zhaob, S.A. Neilda, M.C. Smithc, R. Goodallb and N. Dinmored aFaculty of Engineering, University of Bristol, UK; bInstitute of Railway Research, University of Huddersfield, UK; dDepartment of Engineering, University of Cambridge, UK; eRSSB, London, UK. WORD COUNT: ∼7000 words ARTICLE HISTORY Compiled June 11, 2019 ABSTRACT Improving the track friendliness of a railway vehicle can make a significant con- tribution to improving the overall cost effectiveness of the rail industry. Rail surface damage in curves can be reduced by using vehicles with a lower Primary Yaw Stiff- ness (PYS); however, a lower PYS can reduce high-speed stability and have a nega- tive impact on ride comfort. Previous studies have shown that this trade-off between track friendliness and passenger comfort can be successfully combated by using an inerter in the primary suspension; however, these previous studies used simplified vehicle models, contact models, and track inputs. Considering a realistic four-axle passenger vehicle model, this paper investigates the extent to which the vehicle's PYS can be reduced with inertance-integrated primary lateral suspensions without increasing Root Mean Square (RMS) lateral accelerations when running over a 5 km example track. The vehicle model, with inertance-integrated primary lateral suspen- sions, has been created in VAMPIRE R , and the vehicle dynamics are captured over a range of vehicle velocities and wheel-rail equivalent conicities. Based on systematic optimisations using network-synthesis theory, several beneficial inertance-integrated configurations are identified.
    [Show full text]
  • Estimation of Bogie Performance Criteria Through On-Board Condition Monitoring
    Estimation of Bogie Performance Criteria Through On-Board Condition Monitoring Parham Shahidi1, Dan Maraini1, Brad Hopkins1, and Andrew Seidel1 1Amsted Rail Company, Inc. Chicago, IL, 60606, USA [email protected] [email protected] [email protected] [email protected] ABSTRACT utilize two bogies underneath the car body to carry the lading. Railroad terminology refers to the most widely In this paper, bogie performance criteria are reviewed and it distributed bogie type in North America as the three-piece is shown that a real-time, on-board condition monitoring bogie. Figure 1 gives a general overview of the components system can efficiently monitor these criteria to improve of the three-piece bogie. The three main components of this failure mode detection in freight rail operations. Although system are the two side frames and connecting bolster. the dynamics of rail car bogie performance are well understood in the industry, this topic has recently received renewed attention through impending regulatory changes. These changes seek to extend empty rail car performance criteria to include loaded rail cars as well. Currently, the monitoring of bogie performance is primarily accomplished by wayside detection systems in North America. These systems are only sparsely deployed in the track network and do not offer the ability to monitor bogies continuously. The lack of these elements leads to unexpected downtimes resulting in costly reactive maintenance and lengthy periods of time before an adequate performance history can be established. This paper reviews performance criteria which Figure 1. Standard North American three-piece bogie critically influence bogie performance and proposes a vibration based condition monitoring strategy to estimate This bogie type is also commonly used in Russia, China, system component deterioration and their contribution to the Australia and most African countries.
    [Show full text]
  • Rolling Contact Fatigue Life of Rail for Different Slip Conditions
    2243 Rolling Contact Fatigue Life of Rail for Different Slip Conditions Abstract Jay Prakash Srivastava a,* A three-dimensional elastic-plastic finite element analysis (FEA) is car- Prabir Kumar Sarkar a ried out to estimate the rolling contact fatigue (RCF) crack initiation b V R Kiran Meesala life for varied slip range on the rail arising from operational variations. Vinayak Ranjan c The wheel load produces Hertzian contact pressure. Variation in en- gine traction induces slip variations that evolves thermal load in terms a Department of Mechanical Engineering, of heat flux. The aperiodic rolling of wheel on rail develops non-pro- Indian Institute of Technology (ISM), portional multiaxial fatigue loading. Present study combines these ef- Dhanbad, Jharkhand-826004, INDIA fects by translating the wheel load on rail for multiple (twelve) pass in b Senior Design Engineer, The Tata presence of thermal load, contact pressure and traction through a pro- Power Company Limited Strategic posed simulation. The temperature dependent Chaboche material Engineering Division, Bangalore - model with nonlinear kinematic hardening law is implemented to esti- 560100, INDIA mate the stresses and plastic strains governing the multiaxial fatigue c Department of Mechanical Engineering, condition at the interface. The location of maximum von Mises stress, Bennett University, Greater Noida, Ut- found at a material point on or a layer below the rail-head, contem- tar Pradesh-201310, INDIA plates the fatigue crack initiation site. A coded search algorithm helps to identify the critical plane of crack initiation corresponding to the * Corresponding Author: maximum fatigue parameter (FP). In contrast to available predictions [email protected] of RCF life considering contact pressure and/or traction or frictional heat in isolation, present study combines all these loads together and http://dx.doi.org/10.1590/1679-78254161 provides a more realistic result by numerical simulation.
    [Show full text]
  • Effects of Top-Of-Rail Friction Modifiers on the Friction, Wear and Cracks of Railway Rails
    DOCTORAL T H E SIS Saad Ahmed Khan Saad Department of Civil, Environmental and Natural Resources Engineering Division of Operation, Maintenance and Acoustics ISSN 1402-1544 ISBN 978-91-7790-272-0 (print) ISBN 978-91-7790-273-7 (pdf) Effects of top-of-rail friction modifiers Effects of top-of-rail friction modifiers on the friction, wear and cracks of railway rails and cracks of railway Effects of top-of-rail friction wear modifiers on the friction, Luleå University of Technology 2019 on the friction, wear and cracks of railway rails Saad Ahmed Khan Operation and maintenance engineering Effects of top-of-rail friction modifiers on the friction, wear and cracks of railway rails Saad Ahmed Khan Division of Operation, Maintenance and Acoustics Department of Civil, Environmental and Natural Resources Engineering Luleå University of Technology Printed by Luleå University of Technology, Graphic Production 2019 ISSN 1402-1544 ISBN 978-91-7790-272-0 (print) ISBN 978-91-7790-273-7 (pdf) Luleå 2019 www.ltu.se ACKNOWLEDGEMENTS The research work presented in this thesis was carried out between March 2015 and February 2019 at the Division of Operation, Maintenance and Acoustics of Luleå University of Technology. I gratefully acknowledge Luleå Railway Research Center (JVTC) and the Swedish Transport Administration (Trafikverket) for financing the project. I would like to express my gratitude to my supervisor, Professor Jan Lundberg, and my co-supervisors, Dr Christer Stenström and Associate Professor Matti Rantatalo. I am thankful for the confidence that they have placed in my capability to conduct this research work, and for all their support through sharing their ideas, proposing improvements, proofreading manuscripts, finding new ways, and always adopting a positive approach.
    [Show full text]