The running safety of high-speed trains has become a major concern of the current railway research with the rapid development of high-speed railways around the world.The basic safety requirement is to prevent the dera...The running safety of high-speed trains has become a major concern of the current railway research with the rapid development of high-speed railways around the world.The basic safety requirement is to prevent the derailment.The root causes of the dynamic derailment of highspeed trains operating in severe environments are not easy to identify using the field tests or laboratory experiments.Numerical simulation using an advanced train–track interaction model is a highly efficient and low-cost approach to investigate the dynamic derailment behavior and mechanism of high-speed trains.This paper presents a three-dimensional dynamic model of a high-speed train coupled with a ballast track for dynamic derailment analysis.The model considers a train composed of multiple vehicles and the nonlinear inter-vehicle connections.The ballast track model consists of rails,fastenings,sleepers,ballasts,and roadbed,which are modeled by Euler beams,nonlinear spring-damper elements,equivalent ballast bodies,and continuous viscoelastic elements,in which the modal superposition method was used to reduce the order of the partial differential equations of Euler beams.The commonly used derailment safety assessment criteria around the world are embedded in the simulation model.The train–track model was then used to investigate the dynamic derailment responses of a high-speed train passing over a buckled track,in which the derailmentmechanism and train running posture during the dynamic derailment process were analyzed in detail.The effects of train and track modelling on dynamic derailment analysis were also discussed.The numerical results indicate that the train and track modelling options have a significant effect on the dynamic derailment analysis.The inter-vehicle impacts and the track flexibility and nonlinearity should be considered in the dynamic derailment simulations.展开更多
It is important to study the subgrade characteristics of high-speed railways in consideration of the water–soil coupling dynamic problem,especially when high-speed trains operate in rainy regions.This study develops ...It is important to study the subgrade characteristics of high-speed railways in consideration of the water–soil coupling dynamic problem,especially when high-speed trains operate in rainy regions.This study develops a nonlinear water–soil interaction dynamic model of slab track coupling with subgrade under high-speed train loading based on vehicle–track coupling dynamics.By using this model,the basic dynamic characteristics,including water–soil interaction and without water induced by the high-speed train loading,are studied.The main factors-the permeability coefficien and the porosity-influencin the subgrade deformation are investigated.The developed model can characterize the soil dynamic behaviour more realistically,especially when considering the influenc of water-rich soil.展开更多
Two types of high power alternating current(AC) locomotive in China are prone to serious high-order polygonal wear, which has significant negative effects on the operation of locomotives. This study investigates facto...Two types of high power alternating current(AC) locomotive in China are prone to serious high-order polygonal wear, which has significant negative effects on the operation of locomotives. This study investigates factors influencing polygonal wear in locomotive wheels and determines methods of minimizing operation damage. We designed experiments to analyze the process of polygonization formation of wheels to identify the key influencing factors, finding that natural vibration of wheelsets is the central inherent factor of wheel polygonization and that these vibrations can be easily stimulated by wheel or rail irregularities. We found that poor re-profiling quality is the key external factor in these irregularities. The wheelset bending resonance is activated when the remaining wheel polygonal wear has a wavelength of 200 mm in the 1/3 octave band, in turn leading to significant increases of wheel polygonal wear. In this study, we review a new wheelset design that can mitigate and/or eliminate the polygonal wheel wear due to increased stiffness in wheel bending. We evaluate the potential capacity of the newly designed wheelset and propose two proven effective measures to further improve the wheel re-profiling quality for polygonal wear.展开更多
基金supported by the National Basic Research Program(973)of China(2011CB711103)the National Natural Science Foundation of China(U1134202)+1 种基金the Program for Changjiang Scholars and Innovative Research Team in University(IRT1178 and SWJTU12ZT01)the 2013 Cultivation Program for the Excellent Doctoral Dissertation of Southwest Jiaotong University
文摘The running safety of high-speed trains has become a major concern of the current railway research with the rapid development of high-speed railways around the world.The basic safety requirement is to prevent the derailment.The root causes of the dynamic derailment of highspeed trains operating in severe environments are not easy to identify using the field tests or laboratory experiments.Numerical simulation using an advanced train–track interaction model is a highly efficient and low-cost approach to investigate the dynamic derailment behavior and mechanism of high-speed trains.This paper presents a three-dimensional dynamic model of a high-speed train coupled with a ballast track for dynamic derailment analysis.The model considers a train composed of multiple vehicles and the nonlinear inter-vehicle connections.The ballast track model consists of rails,fastenings,sleepers,ballasts,and roadbed,which are modeled by Euler beams,nonlinear spring-damper elements,equivalent ballast bodies,and continuous viscoelastic elements,in which the modal superposition method was used to reduce the order of the partial differential equations of Euler beams.The commonly used derailment safety assessment criteria around the world are embedded in the simulation model.The train–track model was then used to investigate the dynamic derailment responses of a high-speed train passing over a buckled track,in which the derailmentmechanism and train running posture during the dynamic derailment process were analyzed in detail.The effects of train and track modelling on dynamic derailment analysis were also discussed.The numerical results indicate that the train and track modelling options have a significant effect on the dynamic derailment analysis.The inter-vehicle impacts and the track flexibility and nonlinearity should be considered in the dynamic derailment simulations.
基金supported by the National Natural Science Foundation of China (Grants U1134202,51305360)the National Basic Research Programof China(Grant2011CB711103)the 2015 Doctoral Innovation Funds of Southwest Jiaotong University
文摘It is important to study the subgrade characteristics of high-speed railways in consideration of the water–soil coupling dynamic problem,especially when high-speed trains operate in rainy regions.This study develops a nonlinear water–soil interaction dynamic model of slab track coupling with subgrade under high-speed train loading based on vehicle–track coupling dynamics.By using this model,the basic dynamic characteristics,including water–soil interaction and without water induced by the high-speed train loading,are studied.The main factors-the permeability coefficien and the porosity-influencin the subgrade deformation are investigated.The developed model can characterize the soil dynamic behaviour more realistically,especially when considering the influenc of water-rich soil.
基金supported by the National Basic Research Program(973)of China(No.2011CB711103)the National High-Tech R&D Program(863)of China(No.2011AA11A103-2-2)the National Natural Science Foundations of China(Nos.U1134202,U1434201,and 51475390)
基金supported by the National Natural Science Foundation of China(Nos.U1134202,51275430,and 51305361)the National Basic Research Program (973) of China(No.2011CB711103)the Program for Changjiang Scholars and Innovative Research Team in University(Nos.IRT1178 and SWJTU12ZT01),China
基金supported by the National Natural Science Foundation of China(Nos.51475390 and U1434201)the National High-Tech R&D Program(863)of China(No.2011AA11A103-2-2)the Program for Changjiang Scholars and Innovative Research Team in University(Nos.IRT1178 and SWJTU12ZT01),China
基金supported by the National Natural Science Foundation of China(Nos.51475390 and U1434201)the National High-Tech R&D Program(863)of China(No.2011AA11A103-4-2)+1 种基金the Fundamental Research Funds for the Central Universitiesthe 2013 Doctoral Innovation Funds of Southwest Jiaotong University,China
基金Project supported by the National Natural Science Foundation of China (Nos. 51475390 and U 1434201), the National Key Technology R&D Program of China (Nos. 2016YFB1200506-08 and 2016YFB1200503-02), and the Scientific Research Foundation of State Key Laboratory of Traction Power (No. 2015TPL_T08), China
基金supported by the National Natural Science Foundation of China(No.U1134202)the National Basic Research Program(973)of China(No.2011CB711103)+2 种基金the Program for Changjiang Scholars and Innovative Research Team in University(Nos.IRT1178 and SWJTU12ZT01)the Fundamental Research Funds for the Central Universitiesthe 2014 Doctoral Innovation Funds of Southwest Jiaotong University,China
基金Project supported by the National Natural Science Foundation of China (Nos. U 1434201, 51275427, and 51605394), and the Scientific Research Foundation of State Key Laboratory of Traction Power (No. 2015TPL_T01 ), China
基金supported by the National Natural Science Foundation of China(No.U1134202)the National Basic Research Program(973)of China(No.2011CB711103)+1 种基金the Program for Changjiang Scholars and Innovative Research Team in University(Nos.IRT1178 and SWJTU12ZT01)the 2013 Cultivation Program for the Excellent Doctoral Dissertation of Southwest Jiaotong University,China
基金Project supported by the National Natural Science Foundation of China (Nos. U1434201 and 51475390), the National Key Technology R&D Program of China (Nos. 2016YFB1200503-02 and 2016YFB1200506-08), and the 2015 Doctoral Innovation Funds of Southwest Jiaotong University, China
基金supported by the National Natural Science Foundation oChina(No.U1134202)the National Basic Research Program(973)oChina(No.2011CB711103)+1 种基金the Program for Changjiang Scholarsand Innovative Research Team in University(Nos.IRT1178 andSWJTU12ZT01)the Applied Basic Research Program of SichuanProvince(No.2013JY0039),China
基金Project supported by the National Natural Science Foundation of China(Nos.U1134202 and 51305360)the National Basic Research Program(973 Program) of China(No.2011CB711103)the 2015 Doctoral Innovation Funds of Southwest Jiaotong University,China
基金Project supported by the National Natural Science Foundation of China (No. 51875484)the Scientific Research Foundation of the State Key Laboratory of Traction Power of Southwest Jiaotong University (No. 2017TPL_T05)the Opening Project of The State Key Laboratory of Heavy Duty AC Drive Electric Locomotive Systems Integration (No. 2017ZJKF01),China。
文摘Two types of high power alternating current(AC) locomotive in China are prone to serious high-order polygonal wear, which has significant negative effects on the operation of locomotives. This study investigates factors influencing polygonal wear in locomotive wheels and determines methods of minimizing operation damage. We designed experiments to analyze the process of polygonization formation of wheels to identify the key influencing factors, finding that natural vibration of wheelsets is the central inherent factor of wheel polygonization and that these vibrations can be easily stimulated by wheel or rail irregularities. We found that poor re-profiling quality is the key external factor in these irregularities. The wheelset bending resonance is activated when the remaining wheel polygonal wear has a wavelength of 200 mm in the 1/3 octave band, in turn leading to significant increases of wheel polygonal wear. In this study, we review a new wheelset design that can mitigate and/or eliminate the polygonal wheel wear due to increased stiffness in wheel bending. We evaluate the potential capacity of the newly designed wheelset and propose two proven effective measures to further improve the wheel re-profiling quality for polygonal wear.