Rolling stock manufacturers are finding structural solutions to reduce power required by the vehicles,and the lightweight design of the car body represents a possible solution.Optimization processes and innovative mat...Rolling stock manufacturers are finding structural solutions to reduce power required by the vehicles,and the lightweight design of the car body represents a possible solution.Optimization processes and innovative materials can be combined in order to achieve this goal.In this framework,we propose the redesign and optimization process of the car body roof for a light rail vehicle,introducing a sandwich structure.Bonded joint was used as a fastening system.The project was carried out on a single car of a modern tram platform.This preliminary numerical work was developed in two main steps:redesign of the car body structure and optimization of the innovated system.Objective of the process was the mass reduction of the whole metallic structure,while the constraint condition was imposed on the first frequency of vibration of the system.The effect of introducing a sandwich panel within the roof assembly was evaluated,focusing on the mechanical and dynamic performances of the whole car body.A mass saving of 63%on the optimized components was achieved,corresponding to a 7.6%if compared to the complete car body shell.In addition,a positive increasing of 17.7%on the first frequency of vibration was observed.Encouraging results have been achieved in terms of weight reduction and mechanical behaviour of the innovated car body.展开更多
Automated operation and artificial intelligence technology have become essential for ensuring the safety, efficiency, and punctuality of railways, with applications such as ATO (Automatic Train Operation). In this stu...Automated operation and artificial intelligence technology have become essential for ensuring the safety, efficiency, and punctuality of railways, with applications such as ATO (Automatic Train Operation). In this study, the authors propose a method to efficiently simulate the kinematic characteristics of railroad vehicles depending on their speed zone. They utilized the function overloading function supported by a programming language and applied the fourth-order Lunge-Kutta method for dynamic simulation. By constructing an object model, the authors calculated vehicle characteristics and TPS and compared them with actual values, verifying that the developed model represents the real-life vehicle characteristics accurately. The study highlights potential improvements in automated driving and energy consumption optimization in the railway industry.展开更多
This paper introduces the application of new automatic welding technologies in railway vehicles manufacturing industry, and presents the state of art of advanced friction stir welding technology, semi-penetration lase...This paper introduces the application of new automatic welding technologies in railway vehicles manufacturing industry, and presents the state of art of advanced friction stir welding technology, semi-penetration laser welding technology and laser-arc hybrid welding technology in manufacturing aluminum alloy body shell, stainless steel body shell and bogie. This paper also analyzes the application and development trend of three welding technologies in the future.展开更多
The 2DOF dynamic equations of the doable railway suspended vehicle for automatic transportation in the welding shop are established. The sensitivities are analyzed. The parameter design is researched in ADAMS in terms...The 2DOF dynamic equations of the doable railway suspended vehicle for automatic transportation in the welding shop are established. The sensitivities are analyzed. The parameter design is researched in ADAMS in terms of the inner railway radius, wheelbase, gauge, girder length of the doable railway suspended vehicle for automatic transportation in the welding product line. The mutual-restriction among the design variables is discussed and the selective ranges of the variables are confirmed. The result shows that the stability of the doable railway suspended vehicle for automatic transportation in the welding product line depends on parameters of the inner railway radius, wheelbase, gauge, girder length. The optimal results of the optimal objective and design variables have research significance for the virtual prototype of the doable suspension railway automation vehicle. The optimal results are input into the simulation model iteratively and the simulation results are fed back to the physical prototype. The veracity and reliability of peoformance forecast are improved so that the manufacture cost of the doable suspension railway automation vehicle is reduced significantly.展开更多
Anti-slip control systems are essential for railway vehicle systems with traction.In order to propose an effective anti-slip control system,adhesion information between wheel and rail can be useful.However,direct meas...Anti-slip control systems are essential for railway vehicle systems with traction.In order to propose an effective anti-slip control system,adhesion information between wheel and rail can be useful.However,direct measurement or observation of adhesion condition for a railway vehicle in operation is quite demanding.Therefore,a proportional–integral controller,which operates simultaneously with a recently proposed swarm intelligencebased adhesion estimation algorithm,is proposed in this study.This approach provides determination of the adhesion optimum on the adhesion-slip curve so that a reference slip value for the controller can be determined according to the adhesion conditions between wheel and rail.To validate the methodology,a tram wheel test stand with an independently rotating wheel,which is a model of some low floor trams produced in Czechia,is considered.Results reveal that this new approach is more effective than a conventional controller without adhesion condition estimation.展开更多
Since the concept of active suspensions appeared,its large possible benefits has attracted continuous exploration in the field of railway engineering.With new demands of higher speed,better ride comfort and lower main...Since the concept of active suspensions appeared,its large possible benefits has attracted continuous exploration in the field of railway engineering.With new demands of higher speed,better ride comfort and lower maintenance cost for railway vehicles,active suspensions are very promising technologies.Being the starting point of commercial application of active suspensions in rail vehicles,tilting trains have become a great success in some countries.With increased technical maturity of sensors and actuators,active suspension has unprecedented development opportunities.In this work,the basic concepts are summarized with new theories and solutions that have appeared over the last decade.Experimental studies and the implementation status of different active suspension technologies are described as well.Firstly,tilting trains are briefly described.Thereafter,an indepth study for active secondary and primary suspensions is performed.For both topics,after an introductory section an explanation of possible solutions existing in the literature is given.The implementation status is reported.Active secondary suspensions are categorized into active and semi-active suspensions.Primary suspensions are instead divided between acting on solid-axle wheelsets and independently rotating wheels.Lastly,a brief summary and outlook is presented in terms of benefits,research status and challenges.The potential for active suspensions in railway applications is outlined.展开更多
Virtual prototype is an important idea to resolve design problems of railway vehicle. A different development method, which is based on national product and autonomous development, and would like to reflect the specia...Virtual prototype is an important idea to resolve design problems of railway vehicle. A different development method, which is based on national product and autonomous development, and would like to reflect the specialty of railway vehicle development in China, is presented. According to the developing process of railway vehicle, the research contents and developing method are pointed out. The integration between CAD and performance analysis software on dynamics and strength is mainly considered. In CAD environment, the properties for dynamics computing are extracted directly from the model and exported with model. This method can avoid data losing caused by model rebuilding in CAE software, and increase the direct dependence of product CAD. Then the vehicle model with properties will be used for real-time dynamics and kinematics analysis and simulation. Therefore, the strength of the parts can be analyzed. The results of dynamics and strength analysis will be fed back to optimize the design model. All operations are dispatched by a control platform, and all data are managed according to the principle of PDM. Testing results show this method is correct.展开更多
A state-of-art review is given to the new advances on fatigue reliability design and analysis methods of Chinese railway vehicle's structures. First, the structures are subject to a complicated random fatigue stressi...A state-of-art review is given to the new advances on fatigue reliability design and analysis methods of Chinese railway vehicle's structures. First, the structures are subject to a complicated random fatigue stressing history and this history should be determined by combining dynamic simulation and on-line inspection. Second, the random fatigue constitutions belong to an intrinsic fatigue phenomenon and a probabilistic model is developed to well describe them with two measurements of survival probability and confidence, similar model is also presented for the random stress-life rela- tions and extrapolated appropriately into Song fatigue life regime. Third, concept of the fatigue limit should be understood as the fatigue strength at a given fatigue life and a so-called local Basquin model method is proposed for measuring the random strengths. In addition, drawing and application methods of the Goodman-Smith diagram for integrally characterizing the random fatigue strengths are established in terms of ten kilometers. Fourth, a reliability stress-based method is constructed with a consideration of the random constitutive relations. These new advances form a new frame work for railway fatigue reliability design and analysis.展开更多
The nonlinear hunting stability of railway vehicles is studied theoretically and experimentally in this paper.The Hopf bifurcation point is determined throug...The nonlinear hunting stability of railway vehicles is studied theoretically and experimentally in this paper.The Hopf bifurcation point is determined through calculating the eigenvalues of the system linearization equations incorporating with the golden cut method.The bifurcated limit cycles are computed by use of the shooting method to solve the boundary value problem of the system differential equations.Experimental validation to the numerical results is carricd out by utilizing the full scale roller test rig.展开更多
<span style="font-family:Verdana;">Transportation of freight and passengers by train is one of the oldest types of transport, and has now taken root in most of the developing countries especially in Af...<span style="font-family:Verdana;">Transportation of freight and passengers by train is one of the oldest types of transport, and has now taken root in most of the developing countries especially in Africa. Recently, with the advent and development of high-speed trains, continuous monitoring of the railway vehicle suspension is of significant importance. For this reason, railway vehicles should be monitored continuously to avoid catastrophic events, ensure comfort, safety, and also improved performance while reducing life cycle costs. The suspension system is a very important part of the railway vehicle which supports the car-body and the bogie, isolates the forces generated by the track unevenness at the wheels and also controls the attitude of the car-body with respect to the track surface for ride comfort. Its reliability is directly related to the vehicle safety. The railway vehicle suspension often develops faults;worn springs and dampers in the primary and secondary suspension. To avoid a complete system failure, early detection of fault in the suspension of trains is of high importance. The main contribution of the research work is the prediction of faulty regimes of a</span> <span style="font-family:Verdana;">railway vehicle suspension based on a hybrid model. The hybrid model</span><span style="font-family:Verdana;"> framework is in four folds;first, modeling of vehicle suspension system to generate vertical acceleration of the railway vehicle, parameter estimation or identification was performed to obtain the nominal parameter values of the vehicle suspension system based on the measured data in the second fold, furthermore, a supervised machine learning model was built to predict faulty and healthy state of the suspension system components (damage scenarios) based on support vector machine (SVM) and lastly, the development of a new SVM model with the damage scenarios to predict faults on the test data. The level of degradation at which the spring and damper becomes faulty for both pri</span><span style="font-family:Verdana;">mary and secondary suspension system was determined. The spring and</span><span style="font-family:Verdana;"> damper becomes faulty when the nominal values degrade by 50% and 40% and 30% and 40% for the secondary and primary suspension system respectively. The proposed model was able to predict faulty components with an accuracy of 0.844 for the primary and secondary suspension system.</span>展开更多
Using stochastic dynamic simulation for railway vehicle collision still faces many challenges,such as high modelling complexity and time-consuming.To address the challenges,we introduce a novel data-driven stochastic ...Using stochastic dynamic simulation for railway vehicle collision still faces many challenges,such as high modelling complexity and time-consuming.To address the challenges,we introduce a novel data-driven stochastic process modelling(DSPM)approach into dynamic simulation of the railway vehicle collision.This DSPM approach consists of two steps:(i)process description,four kinds of kernels are used to describe the uncertainty inherent in collision processes;(ii)solving,stochastic variational inferences and mini-batch algorithms can then be used to accelerate computations of stochastic processes.By applying DSPM,Gaussian process regression(GPR)and finite element(FE)methods to two collision scenarios(i.e.lead car colliding with a rigid wall,and the lead car colliding with another lead car),we are able to achieve a comprehensive analysis.The comparison between the DSPM approach and the FE method revealed that the DSPM approach is capable of calculating the corresponding confidence interval,simultaneously improving the overall computational efficiency.Comparing the DSPM approach with the GPR method indicates that the DSPM approach has the ability to accurately describe the dynamic response under unknown conditions.Overall,this research demonstrates the feasibility and usability of the proposed DSPM approach for stochastic dynamics simulation of the railway vehicle collision.展开更多
Changchun Railway Vehicle Co.,Ltd.(CRC) was founded in March 2002.Initiated by China's North Locomotive & Rolling Stock Industry (group) Corporation,and based on the main business as well as the capital of the...Changchun Railway Vehicle Co.,Ltd.(CRC) was founded in March 2002.Initiated by China's North Locomotive & Rolling Stock Industry (group) Corporation,and based on the main business as well as the capital of the former Changchun Car Company,CRC was founded as new joint-stock company,展开更多
The relevant standard requirements both in domestic and abroad provide the basis for designing air-conditioning system of railway vehicles present. However, there are great differences in the fresh air volume indicato...The relevant standard requirements both in domestic and abroad provide the basis for designing air-conditioning system of railway vehicles present. However, there are great differences in the fresh air volume indicators among different standards requirements, and the requirements of each vehicle procurement contracts are also different. The design of air-conditioning become difficult above these. In this paper, the fresh air volume of different type railway vehicles is analyzed from health and equipment electricity consumption according to the railway vehicles air-conditioning system standard requirements in domestic and abroad. Some advises for designing air-conditioning system of railway vehicles through the fresh air volume calculation and comparison for domestic air-conditioning system of railway vehicles was provided.展开更多
The study of nonlinear oscillations and chaos of a railway freight car is undertaken. The vehicle is considered as a multiple rigid body system with 9 degrees of freedom. The vehicle forward speed is taken as the con...The study of nonlinear oscillations and chaos of a railway freight car is undertaken. The vehicle is considered as a multiple rigid body system with 9 degrees of freedom. The vehicle forward speed is taken as the control parameter of the system. Hopf bifurcation point, limit cycles, quasiperiodic and chaotic motions of the system are computed by use of numerical methods. The identification of periodic, quasiperiodic and chaotic motions of the system is carried out by using the methods of phase plane portrait and Poincare map. Numerical results show that chaotic motion appears via the route of quasiperiodicity when the vehicle runs over a certain speed.展开更多
A comprehensive modeling strategy for studying the thermomechanical tribological behaviors is proposed in this work.The wear degradation considering the influence of temperature(T)is predicted by Archard wear model wi...A comprehensive modeling strategy for studying the thermomechanical tribological behaviors is proposed in this work.The wear degradation considering the influence of temperature(T)is predicted by Archard wear model with the help of the UMESHMOTION subroutine and arbitrary Lagrangian–Eulerian(ALE)remeshing technique.Adopting the proposed method,the thermomechanical tribological behaviors of railway vehicle disc brake system composed of forged steel brake disc and Cu-based powder metallurgy(PM)friction block are studied systematically.The effectiveness of the proposed methodology is validated by experimental test on a self-designed scaled brake test bench from the perspectives of interface temperature,wear degradation,friction noise and vibration,and contact status evolution.This work can provide an effective way for the investigation of thermomechanical tribological behaviors in the engineering field.展开更多
In order to reduce the wheel profile wear of highspeed trains and extend the service life of wheels, a dynamic model for a high-speed vehicle was set up, in which the wheelset was regarded as flexible body, and the ac...In order to reduce the wheel profile wear of highspeed trains and extend the service life of wheels, a dynamic model for a high-speed vehicle was set up, in which the wheelset was regarded as flexible body, and the actual measured track irregularities and line conditions were considered. The wear depth of the wheel profile was calculated by the well-known Archard wear law. Through this model, the influence of the wheel profile, primary suspension stiffness, track gage, and rail cant on the wear of wheel profile were studied through multiple iterafive calculations. Numerical simulation results show that the type XP55 wheel profile has the smallest cumulative wear depth, and the type LM wheel profile has the largest wear depth. To reduce the wear of the wheel profile, the equivalent conicity of the wheel should not be too large or too small. On the other hand, a small primary vertical stiffness, a track gage around 1,435-1,438 mm, and a rail cant around 1:35-1:40 are beneficial for dynamic performance improvement and wheel wear alleviation.展开更多
A theoretical model has been developed to investigate vertical dynamic interactions between railway vehicles and tracks. Wheel rail forces and dynamic responses of vehicle and track components can be simulated with...A theoretical model has been developed to investigate vertical dynamic interactions between railway vehicles and tracks. Wheel rail forces and dynamic responses of vehicle and track components can be simulated with the model. The model has been applied to the study of high speed and heavy haul railway dynamic problems. In order to verify the model completely, a full scale field experiment was performed on the Chinese Datong Qinhuangdao railway. Accelerations of rail, sleeper and ballast were measured and compared with the simulated results both in time domain and in frequency domain.展开更多
Polygonisation is a common nonuniform wear phenomenon occurring in railway vehicle wheels and has a severe impact on the vehicle–track system,ride comfort,and lineside residents.This paper first summarizes periodic d...Polygonisation is a common nonuniform wear phenomenon occurring in railway vehicle wheels and has a severe impact on the vehicle–track system,ride comfort,and lineside residents.This paper first summarizes periodic defects of the wheels,including wheel polygonisation and wheel corrugation,occurring in railways worldwide.Thereafter,the effects of wheel polygonisation on the wheel–rail interaction,noise and vibration,and fatigue failure of the vehicle and track components are reviewed.Based on the different causes,the formation mechanisms of periodic wheel defects are classified into three categories:(1)initial defects of wheels,(2)natural vibration of the vehicle–track system,and(3)thermoelastic instability.In addition,the simulation methods of wheel polygonisation evolution and countermeasures to mitigate wheel polygonisation are presented.Emphasis is given to the characteristics,effects,causes,and solutions of wheel polygonisation in metro vehicles,locomotives,and highspeed trains in China.Finally,the guidance is provided on further understanding the formation mechanisms,monitoring technology,and maintenance criterion of wheel polygonisation.展开更多
The brake unit bracket of a bogie frame is an important load-carrying component, particularly under emergency start/stop conditions. Conventional infinite/safe life approaches provide an over-conservative recommendati...The brake unit bracket of a bogie frame is an important load-carrying component, particularly under emergency start/stop conditions. Conventional infinite/safe life approaches provide an over-conservative recommendation for the allowable strength and lifetime, which hinders the lightweight design of modern railway vehicles. In this study, to ensure the reliability and durability of a brake unit bracket, an attempt was made to integrate the nominal stress method and an advanced damage tolerance method. First, a complex bogie frame was modelled using solid elements instead of plate and beam elements. A hot spot stress region on the bracket was found under an eight-stage load spectrum obtained from the Wuhan–Guangzhou high-speed railway line. Based on the probability of foreign damage, a semi-elliptical surface crack was then assumed for residual life assessment. The results obtained by the cumulative damage and damage tolerance methods show that the brake unit bracket can operate for over 30 years. Moreover, even if a 2-mm depth crack exists, the brake unit bracket can be safely operated for more than 2.27 years, with the hope that the crack can be detected in subsequent maintenance procedures. Finally, an appropriate safety margin was suggested which provides a basis for the life prediction and durability assessment of brake unit brackets of high-speed railways.展开更多
Taking Beijing–Shanghai High-speed Railway(the section of Zhenjiangnan Station) for example,this paper applied UAV remote sensing data and GIS spatial analysis to analyze current land use types in this section,on thi...Taking Beijing–Shanghai High-speed Railway(the section of Zhenjiangnan Station) for example,this paper applied UAV remote sensing data and GIS spatial analysis to analyze current land use types in this section,on this basis used landscape pattern indices that showed high correlation with land use changes for the quantitative analysis and evaluation of ecosystem structure in the study area and also landscape pattern after the construction of high-speed railway.The results showed that UAV images performed well in the evaluation of railway landscape ecological environment,landscape structure and features represented by the selected landscape pattern indices in this paper were applicable,and capable of ensuring scientific evaluation of ecological environmental impact;the overall landscape pattern of the Zhenjiangnan Station section(Beijing–Shanghai High-speed Railway) after completion was moderate,and local ecosystem was damaged,thus scientific and reasonable ecological planning was required to design and change landscape structure.展开更多
文摘Rolling stock manufacturers are finding structural solutions to reduce power required by the vehicles,and the lightweight design of the car body represents a possible solution.Optimization processes and innovative materials can be combined in order to achieve this goal.In this framework,we propose the redesign and optimization process of the car body roof for a light rail vehicle,introducing a sandwich structure.Bonded joint was used as a fastening system.The project was carried out on a single car of a modern tram platform.This preliminary numerical work was developed in two main steps:redesign of the car body structure and optimization of the innovated system.Objective of the process was the mass reduction of the whole metallic structure,while the constraint condition was imposed on the first frequency of vibration of the system.The effect of introducing a sandwich panel within the roof assembly was evaluated,focusing on the mechanical and dynamic performances of the whole car body.A mass saving of 63%on the optimized components was achieved,corresponding to a 7.6%if compared to the complete car body shell.In addition,a positive increasing of 17.7%on the first frequency of vibration was observed.Encouraging results have been achieved in terms of weight reduction and mechanical behaviour of the innovated car body.
文摘Automated operation and artificial intelligence technology have become essential for ensuring the safety, efficiency, and punctuality of railways, with applications such as ATO (Automatic Train Operation). In this study, the authors propose a method to efficiently simulate the kinematic characteristics of railroad vehicles depending on their speed zone. They utilized the function overloading function supported by a programming language and applied the fourth-order Lunge-Kutta method for dynamic simulation. By constructing an object model, the authors calculated vehicle characteristics and TPS and compared them with actual values, verifying that the developed model represents the real-life vehicle characteristics accurately. The study highlights potential improvements in automated driving and energy consumption optimization in the railway industry.
文摘This paper introduces the application of new automatic welding technologies in railway vehicles manufacturing industry, and presents the state of art of advanced friction stir welding technology, semi-penetration laser welding technology and laser-arc hybrid welding technology in manufacturing aluminum alloy body shell, stainless steel body shell and bogie. This paper also analyzes the application and development trend of three welding technologies in the future.
基金Supported by Country Innovative Fund Project(05C26112200399)
文摘The 2DOF dynamic equations of the doable railway suspended vehicle for automatic transportation in the welding shop are established. The sensitivities are analyzed. The parameter design is researched in ADAMS in terms of the inner railway radius, wheelbase, gauge, girder length of the doable railway suspended vehicle for automatic transportation in the welding product line. The mutual-restriction among the design variables is discussed and the selective ranges of the variables are confirmed. The result shows that the stability of the doable railway suspended vehicle for automatic transportation in the welding product line depends on parameters of the inner railway radius, wheelbase, gauge, girder length. The optimal results of the optimal objective and design variables have research significance for the virtual prototype of the doable suspension railway automation vehicle. The optimal results are input into the simulation model iteratively and the simulation results are fed back to the physical prototype. The veracity and reliability of peoformance forecast are improved so that the manufacture cost of the doable suspension railway automation vehicle is reduced significantly.
基金supported by University of Pardubice,Czechia,Eskisehir Technical University,Turkey,and Newcastle University,United Kingdom.
文摘Anti-slip control systems are essential for railway vehicle systems with traction.In order to propose an effective anti-slip control system,adhesion information between wheel and rail can be useful.However,direct measurement or observation of adhesion condition for a railway vehicle in operation is quite demanding.Therefore,a proportional–integral controller,which operates simultaneously with a recently proposed swarm intelligencebased adhesion estimation algorithm,is proposed in this study.This approach provides determination of the adhesion optimum on the adhesion-slip curve so that a reference slip value for the controller can be determined according to the adhesion conditions between wheel and rail.To validate the methodology,a tram wheel test stand with an independently rotating wheel,which is a model of some low floor trams produced in Czechia,is considered.Results reveal that this new approach is more effective than a conventional controller without adhesion condition estimation.
基金Funding was provided by Horizon 2020 Framework Programme(Grant No.777564).
文摘Since the concept of active suspensions appeared,its large possible benefits has attracted continuous exploration in the field of railway engineering.With new demands of higher speed,better ride comfort and lower maintenance cost for railway vehicles,active suspensions are very promising technologies.Being the starting point of commercial application of active suspensions in rail vehicles,tilting trains have become a great success in some countries.With increased technical maturity of sensors and actuators,active suspension has unprecedented development opportunities.In this work,the basic concepts are summarized with new theories and solutions that have appeared over the last decade.Experimental studies and the implementation status of different active suspension technologies are described as well.Firstly,tilting trains are briefly described.Thereafter,an indepth study for active secondary and primary suspensions is performed.For both topics,after an introductory section an explanation of possible solutions existing in the literature is given.The implementation status is reported.Active secondary suspensions are categorized into active and semi-active suspensions.Primary suspensions are instead divided between acting on solid-axle wheelsets and independently rotating wheels.Lastly,a brief summary and outlook is presented in terms of benefits,research status and challenges.The potential for active suspensions in railway applications is outlined.
基金supported by National Science Found for Distinguished Young Scholars of China (No.50525518).
文摘Virtual prototype is an important idea to resolve design problems of railway vehicle. A different development method, which is based on national product and autonomous development, and would like to reflect the specialty of railway vehicle development in China, is presented. According to the developing process of railway vehicle, the research contents and developing method are pointed out. The integration between CAD and performance analysis software on dynamics and strength is mainly considered. In CAD environment, the properties for dynamics computing are extracted directly from the model and exported with model. This method can avoid data losing caused by model rebuilding in CAE software, and increase the direct dependence of product CAD. Then the vehicle model with properties will be used for real-time dynamics and kinematics analysis and simulation. Therefore, the strength of the parts can be analyzed. The results of dynamics and strength analysis will be fed back to optimize the design model. All operations are dispatched by a control platform, and all data are managed according to the principle of PDM. Testing results show this method is correct.
基金Selected from Proceedings of the 7th International Conference on Frontiers of Design and Manufacturing(ICFDM'2006)This project is supported by National Natural Science Foundation of China(No.50375130,No.50575189)+1 种基金Foundation for the Author of National Excellent Doctoral Dissertation of China(No.2002034)Program for New Century Excellent Talents in University,China(No.040890).
文摘A state-of-art review is given to the new advances on fatigue reliability design and analysis methods of Chinese railway vehicle's structures. First, the structures are subject to a complicated random fatigue stressing history and this history should be determined by combining dynamic simulation and on-line inspection. Second, the random fatigue constitutions belong to an intrinsic fatigue phenomenon and a probabilistic model is developed to well describe them with two measurements of survival probability and confidence, similar model is also presented for the random stress-life rela- tions and extrapolated appropriately into Song fatigue life regime. Third, concept of the fatigue limit should be understood as the fatigue strength at a given fatigue life and a so-called local Basquin model method is proposed for measuring the random strengths. In addition, drawing and application methods of the Goodman-Smith diagram for integrally characterizing the random fatigue strengths are established in terms of ten kilometers. Fourth, a reliability stress-based method is constructed with a consideration of the random constitutive relations. These new advances form a new frame work for railway fatigue reliability design and analysis.
文摘The nonlinear hunting stability of railway vehicles is studied theoretically and experimentally in this paper.The Hopf bifurcation point is determined through calculating the eigenvalues of the system linearization equations incorporating with the golden cut method.The bifurcated limit cycles are computed by use of the shooting method to solve the boundary value problem of the system differential equations.Experimental validation to the numerical results is carricd out by utilizing the full scale roller test rig.
文摘<span style="font-family:Verdana;">Transportation of freight and passengers by train is one of the oldest types of transport, and has now taken root in most of the developing countries especially in Africa. Recently, with the advent and development of high-speed trains, continuous monitoring of the railway vehicle suspension is of significant importance. For this reason, railway vehicles should be monitored continuously to avoid catastrophic events, ensure comfort, safety, and also improved performance while reducing life cycle costs. The suspension system is a very important part of the railway vehicle which supports the car-body and the bogie, isolates the forces generated by the track unevenness at the wheels and also controls the attitude of the car-body with respect to the track surface for ride comfort. Its reliability is directly related to the vehicle safety. The railway vehicle suspension often develops faults;worn springs and dampers in the primary and secondary suspension. To avoid a complete system failure, early detection of fault in the suspension of trains is of high importance. The main contribution of the research work is the prediction of faulty regimes of a</span> <span style="font-family:Verdana;">railway vehicle suspension based on a hybrid model. The hybrid model</span><span style="font-family:Verdana;"> framework is in four folds;first, modeling of vehicle suspension system to generate vertical acceleration of the railway vehicle, parameter estimation or identification was performed to obtain the nominal parameter values of the vehicle suspension system based on the measured data in the second fold, furthermore, a supervised machine learning model was built to predict faulty and healthy state of the suspension system components (damage scenarios) based on support vector machine (SVM) and lastly, the development of a new SVM model with the damage scenarios to predict faults on the test data. The level of degradation at which the spring and damper becomes faulty for both pri</span><span style="font-family:Verdana;">mary and secondary suspension system was determined. The spring and</span><span style="font-family:Verdana;"> damper becomes faulty when the nominal values degrade by 50% and 40% and 30% and 40% for the secondary and primary suspension system respectively. The proposed model was able to predict faulty components with an accuracy of 0.844 for the primary and secondary suspension system.</span>
基金supported by the National Key Research and Development Project(No.2019YFB1405401)the National Natural Science Foundation of China(No.5217120056)。
文摘Using stochastic dynamic simulation for railway vehicle collision still faces many challenges,such as high modelling complexity and time-consuming.To address the challenges,we introduce a novel data-driven stochastic process modelling(DSPM)approach into dynamic simulation of the railway vehicle collision.This DSPM approach consists of two steps:(i)process description,four kinds of kernels are used to describe the uncertainty inherent in collision processes;(ii)solving,stochastic variational inferences and mini-batch algorithms can then be used to accelerate computations of stochastic processes.By applying DSPM,Gaussian process regression(GPR)and finite element(FE)methods to two collision scenarios(i.e.lead car colliding with a rigid wall,and the lead car colliding with another lead car),we are able to achieve a comprehensive analysis.The comparison between the DSPM approach and the FE method revealed that the DSPM approach is capable of calculating the corresponding confidence interval,simultaneously improving the overall computational efficiency.Comparing the DSPM approach with the GPR method indicates that the DSPM approach has the ability to accurately describe the dynamic response under unknown conditions.Overall,this research demonstrates the feasibility and usability of the proposed DSPM approach for stochastic dynamics simulation of the railway vehicle collision.
文摘Changchun Railway Vehicle Co.,Ltd.(CRC) was founded in March 2002.Initiated by China's North Locomotive & Rolling Stock Industry (group) Corporation,and based on the main business as well as the capital of the former Changchun Car Company,CRC was founded as new joint-stock company,
文摘The relevant standard requirements both in domestic and abroad provide the basis for designing air-conditioning system of railway vehicles present. However, there are great differences in the fresh air volume indicators among different standards requirements, and the requirements of each vehicle procurement contracts are also different. The design of air-conditioning become difficult above these. In this paper, the fresh air volume of different type railway vehicles is analyzed from health and equipment electricity consumption according to the railway vehicles air-conditioning system standard requirements in domestic and abroad. Some advises for designing air-conditioning system of railway vehicles through the fresh air volume calculation and comparison for domestic air-conditioning system of railway vehicles was provided.
文摘The study of nonlinear oscillations and chaos of a railway freight car is undertaken. The vehicle is considered as a multiple rigid body system with 9 degrees of freedom. The vehicle forward speed is taken as the control parameter of the system. Hopf bifurcation point, limit cycles, quasiperiodic and chaotic motions of the system are computed by use of numerical methods. The identification of periodic, quasiperiodic and chaotic motions of the system is carried out by using the methods of phase plane portrait and Poincare map. Numerical results show that chaotic motion appears via the route of quasiperiodicity when the vehicle runs over a certain speed.
基金financial support of the National Natural Science Foundation of China(52105160 and U22A20181)the Natural Science Foundation of Sichuan Province(2022NSFSC1877)+1 种基金China Postdoctoral Science Foundation(2022M720537)the Fundamental Research Funds for the Central Universities(2682021CX028).
文摘A comprehensive modeling strategy for studying the thermomechanical tribological behaviors is proposed in this work.The wear degradation considering the influence of temperature(T)is predicted by Archard wear model with the help of the UMESHMOTION subroutine and arbitrary Lagrangian–Eulerian(ALE)remeshing technique.Adopting the proposed method,the thermomechanical tribological behaviors of railway vehicle disc brake system composed of forged steel brake disc and Cu-based powder metallurgy(PM)friction block are studied systematically.The effectiveness of the proposed methodology is validated by experimental test on a self-designed scaled brake test bench from the perspectives of interface temperature,wear degradation,friction noise and vibration,and contact status evolution.This work can provide an effective way for the investigation of thermomechanical tribological behaviors in the engineering field.
基金the support of the National Natural Science Foundation of China (No. 51005189)the National Key Technology R&D Program of China (2009BAG12A01)
文摘In order to reduce the wheel profile wear of highspeed trains and extend the service life of wheels, a dynamic model for a high-speed vehicle was set up, in which the wheelset was regarded as flexible body, and the actual measured track irregularities and line conditions were considered. The wear depth of the wheel profile was calculated by the well-known Archard wear law. Through this model, the influence of the wheel profile, primary suspension stiffness, track gage, and rail cant on the wear of wheel profile were studied through multiple iterafive calculations. Numerical simulation results show that the type XP55 wheel profile has the smallest cumulative wear depth, and the type LM wheel profile has the largest wear depth. To reduce the wear of the wheel profile, the equivalent conicity of the wheel should not be too large or too small. On the other hand, a small primary vertical stiffness, a track gage around 1,435-1,438 mm, and a rail cant around 1:35-1:40 are beneficial for dynamic performance improvement and wheel wear alleviation.
文摘A theoretical model has been developed to investigate vertical dynamic interactions between railway vehicles and tracks. Wheel rail forces and dynamic responses of vehicle and track components can be simulated with the model. The model has been applied to the study of high speed and heavy haul railway dynamic problems. In order to verify the model completely, a full scale field experiment was performed on the Chinese Datong Qinhuangdao railway. Accelerations of rail, sleeper and ballast were measured and compared with the simulated results both in time domain and in frequency domain.
基金the National Natural Science Foundation of China(Grant Nos.51875484,U1734201,51805450,51775455,U1434201 and 51475390)the Science and Technology Program of Sichuan Province of China(Grant No.2020YFQ0024)+1 种基金the Scientific Research Foundation of the State Key Laboratory of Traction Power of Southwest Jiaotong University(Grant Nos.2020TPL-T03 and 2020TPL-T12)China Postdoctoral Science Foundation(Grant No.2020M673281).
文摘Polygonisation is a common nonuniform wear phenomenon occurring in railway vehicle wheels and has a severe impact on the vehicle–track system,ride comfort,and lineside residents.This paper first summarizes periodic defects of the wheels,including wheel polygonisation and wheel corrugation,occurring in railways worldwide.Thereafter,the effects of wheel polygonisation on the wheel–rail interaction,noise and vibration,and fatigue failure of the vehicle and track components are reviewed.Based on the different causes,the formation mechanisms of periodic wheel defects are classified into three categories:(1)initial defects of wheels,(2)natural vibration of the vehicle–track system,and(3)thermoelastic instability.In addition,the simulation methods of wheel polygonisation evolution and countermeasures to mitigate wheel polygonisation are presented.Emphasis is given to the characteristics,effects,causes,and solutions of wheel polygonisation in metro vehicles,locomotives,and highspeed trains in China.Finally,the guidance is provided on further understanding the formation mechanisms,monitoring technology,and maintenance criterion of wheel polygonisation.
基金Supported by National Natural Science Foundation of China(Grant No.11572267)Sichuan Science and Technology Program(Grant No.2017JY0216)+1 种基金Open Research Project of State Key Laboratory for Strength and Vibration of Mechanical Structures of China(Grant No.SV2016-KF-21)Open Research Project of State Key Laboratory of Traction Power of China(Grant No.2018TPL_T03)
文摘The brake unit bracket of a bogie frame is an important load-carrying component, particularly under emergency start/stop conditions. Conventional infinite/safe life approaches provide an over-conservative recommendation for the allowable strength and lifetime, which hinders the lightweight design of modern railway vehicles. In this study, to ensure the reliability and durability of a brake unit bracket, an attempt was made to integrate the nominal stress method and an advanced damage tolerance method. First, a complex bogie frame was modelled using solid elements instead of plate and beam elements. A hot spot stress region on the bracket was found under an eight-stage load spectrum obtained from the Wuhan–Guangzhou high-speed railway line. Based on the probability of foreign damage, a semi-elliptical surface crack was then assumed for residual life assessment. The results obtained by the cumulative damage and damage tolerance methods show that the brake unit bracket can operate for over 30 years. Moreover, even if a 2-mm depth crack exists, the brake unit bracket can be safely operated for more than 2.27 years, with the hope that the crack can be detected in subsequent maintenance procedures. Finally, an appropriate safety margin was suggested which provides a basis for the life prediction and durability assessment of brake unit brackets of high-speed railways.
基金Sponsored by Environmental Protection Fund of China-"123 Project"of Liaoning Environmental Scientific Research&Education(CEPF2010-123-2-10)
文摘Taking Beijing–Shanghai High-speed Railway(the section of Zhenjiangnan Station) for example,this paper applied UAV remote sensing data and GIS spatial analysis to analyze current land use types in this section,on this basis used landscape pattern indices that showed high correlation with land use changes for the quantitative analysis and evaluation of ecosystem structure in the study area and also landscape pattern after the construction of high-speed railway.The results showed that UAV images performed well in the evaluation of railway landscape ecological environment,landscape structure and features represented by the selected landscape pattern indices in this paper were applicable,and capable of ensuring scientific evaluation of ecological environmental impact;the overall landscape pattern of the Zhenjiangnan Station section(Beijing–Shanghai High-speed Railway) after completion was moderate,and local ecosystem was damaged,thus scientific and reasonable ecological planning was required to design and change landscape structure.