This paper reviews the current status of investigation on snow accumulation on the bogies of high-speed trains(HSTs) running in snowy region. First, the background of the snow issue occurring to the HST and the contra...This paper reviews the current status of investigation on snow accumulation on the bogies of high-speed trains(HSTs) running in snowy region. First, the background of the snow issue occurring to the HST and the contra-measures for the snow issue proposed in the past decades are provided by reviewing previous studies. Next, the methodology for investigating the snow issue developed by High-Speed Train Research Center of Central South University is introduced, including the numerical simulation research platform and the experimental devices for two-phase flow wind tunnel tests. Then, effective anti-snow flow control schemes for guiding the underbody airflow and their impact on the motion and accretion of snow in the installation region of the bogies are presented. Finally, the remaining investigating challenge for the snow issue of HST and the future research with respect to the challenge are provided from an engineering application viewpoint.展开更多
The current research of rail corrugation mainly focuses on the mechanisms of its formation and development. Compared with the root causes and development mechanisms, the wheel-rail impacts, the fatigue failure of vehi...The current research of rail corrugation mainly focuses on the mechanisms of its formation and development. Compared with the root causes and development mechanisms, the wheel-rail impacts, the fatigue failure of vehicle-track parts, and the loss of ride comfort due to rail corrugation should also be taken into account. However, the influences of rail corrugation on vehicle and track vibration, and failure of vehicle and track structural parts are barely discussed in the literature. This paper presents an experimental and numerical investigation of the structural vibration of metro bogies caused by rail corrugation. Extensive experiments are conducted to investigate the effects of short-pitch rail corrugation on the vibration accelerations of metro bogies. A dynamic model of a metro vehicle coupled with a concrete track is established to study the influence of rail corrugation on the structural vibration of metro bogies. The field test results indicate that the short-pitch rail corrugation generates strong vibrations on the axle-boxes and the bogie frames, therefore, accelerates the fatigue failure of the bogie components. The numerical results show that short-pitch rail corrugation may largely reduce the fatigue life of the coil spring, and improving the damping value of the primary vertical dampers is likely to reduce the strong vibration induced by short-pitch rail corrugation. This research systematically studies the effect of rail corrugation on the vibration of metro bogies and proposes some remedies for mitigating strong vibrations of metro bogies and reducing the incidence of failure in primary coil springs, which would be helpful in developing new metro bogies and track maintenance procedures.展开更多
Studies have shown that Zhuan K6 bogies can effectively reduce wheel-rail wear and consumption of heavy-duty trains and enhance vehicle vertical dynamic performance. However, in recent years, during the operation and ...Studies have shown that Zhuan K6 bogies can effectively reduce wheel-rail wear and consumption of heavy-duty trains and enhance vehicle vertical dynamic performance. However, in recent years, during the operation and maintenance of Zhuan K6 bogies, it has been discovered that two common operating failures of Zhuan K6 bogies need further improvement. The two major problems of wheel/rail unilateral wear, consumption and axle box rubber pads cracking and peeling, which are exposed during the operation of the Zhuan K6 bogie, are analyzed, the reasons are found and corresponding countermeasures are put forward.展开更多
Clarifying the correlation of multi-level mechanical parameters of structures in complex dynamic systems is a prerequisite for determining the accruing fatigue damage.In this paper,we adopt the independent component a...Clarifying the correlation of multi-level mechanical parameters of structures in complex dynamic systems is a prerequisite for determining the accruing fatigue damage.In this paper,we adopt the independent component analysis algorithm in unsupervised learning and tap the latent correlation between measured forces and stresses of high-speed train bogies.It is revealed that there exists a strong correlation between the vertical force and the stress at the junction of the transverse beam and the side frame,a site prone to fatigue.Stresses reconstructed by strongly correlated independent components account for more than 70%of the fatigue damage,which in turn supports the finding that the vertical forces are the main contribution to the fatigu e damage at the junction of the transverse beam and the side frame.This strong correlation between vertical forces and stresses effectively reduce the error in fatigue damage prediction and provide insights into fatigue life enhancement of critical structures of dynamic systems beyond high-speed trains.展开更多
In strong wind-snow environments,the icing phenomenon in the bogie region can adversely affect the operational safety of highspeed trains.This study aims to design an ice-melting system that applies to high-speed trai...In strong wind-snow environments,the icing phenomenon in the bogie region can adversely affect the operational safety of highspeed trains.This study aims to design an ice-melting system that applies to high-speed train bogies and investigate its de-icing performance.The icing experiments with a scaled real bogie were first conducted in the icing and snowing wind tunnel at Central South University in China to obtain the icing distribution and thickness characteristics in the bogie region.Based on the results of icing experiments,a heating ice-melting system was designed,and the flat plate ice-melting experiments with different ice thicknesses were further carried out.The influence of ice-melting power,ice thickness,and the angle between the ice layer and the incoming flow on ice-melting characteristics was comprehensively analyzed.Findings indicate that ice-melting power and ice thickness are negatively and positively correlated with ice-melting time,respectively.As the angle between the ice layer and the incoming flow increases,the ice-melting time first increases and then decreases.Additionally,considering ice-melting energy consumption,lower ice-melting power results in reduced energy consumption for the same ice thickness and inclination angle.The ice-melting characteristics obtained in this study can provide valuable information and insights for the design of bogie ice-melting schemes and ice-melting energy saving for high-speed trains operating in cold regions.展开更多
Size and weight limitations mean that ordinary railway vehicles with two double-axle bogies cannot deliver some extremely heavy cargo and products.Thus,a newly designed high-speed freight electric multiple unit(EMU)eq...Size and weight limitations mean that ordinary railway vehicles with two double-axle bogies cannot deliver some extremely heavy cargo and products.Thus,a newly designed high-speed freight electric multiple unit(EMU)equipped with two bogie groups each with two double-axle bogies connected by a transition frame is an alternative means of transporting heavy products because of its greater load capacity.However,because it is still in the design stage,its dynamic performance is yet to be researched,something that is urgently required because of the more-complicated structure and more-intensive wheel-rail interactions than those of traditional high-speed railway vehicles.Therefore,to reveal the dynamic performance,this study establishes a three-dimensional dynamic model of a trailer vehicle in a high-speed freight EMU equipped with four double-axle bogies based on the classical theory of vehicle-track coupled dynamics.In this dynamic model,the vertical,horizontal,rolling,pitching,and yaw motions of the major components excited by random irregularities in the track geometry are considered fully.The results indicate that the derailment coefficient and stability index of this vehicle are both at excellent levels for the simulated conditions.The wheel unloading ratio appears to be larger but still within the safety range when the vehicle runs in a straight line,but it is close to or can even exceed the limit value when the vehicle runs at 400 km/h on a specified curved line.展开更多
Digital twin is one of the key technologies driving the digitalization and intelligence of railway transportation equipment.The development of enabling technologies such as big data,industrial internet of things,and a...Digital twin is one of the key technologies driving the digitalization and intelligence of railway transportation equipment.The development of enabling technologies such as big data,industrial internet of things,and artificial intelligence has facilitated the deep integration of digital twin technology with railway transportation,promoting the high-quality development of the railway transportation industry.This paper studies the design,manufacturing,operation,and maintenance scenarios and requirements of high-speed train sets.Based on the current status of the application and development trends of digital twin technology,it proposes the overall architecture and functional architecture of a digital train for high-speed train sets.The paper also presents the engineering implementation of key high-speed train set bogie systems,providing valuable information for the future construction of digital trains for high-speed train sets.展开更多
Purpose–This paper aims to offer a novel viewpoint for improving performance and reliability by developing and optimizing suspension components in a Y25 bogie through material optimization based on wheel–rail intera...Purpose–This paper aims to offer a novel viewpoint for improving performance and reliability by developing and optimizing suspension components in a Y25 bogie through material optimization based on wheel–rail interactions under variable load and track conditions.Design/methodology/approach–The suspension system,a critical component ensuring adaptation to road and load conditions in all vehicle types,is especially vital in heavy freight and passenger trains.In this context,the suspension set of the Y25 bogie–commonly used in T€urkiye and Europe–was modelled using CATIAV5,and stress analyses have been performed by way of ANSYS using the finite element analysis(FEA)method.E300-520-M cast steel was selected for the bogie frame,while two different spring steels,61SiCr7 and 51CrV4,were considered for the suspension springs.The modeled system was subjected to numerical analysis under loading conditions.The resulting stresses and displacements were compared with the mechanical properties of the selected materials to validate the design.Findings–The results demonstrate that the mechanical strength and deformation characteristics of the suspension components vary according to the applied external loads.The stress and displacement responses of the system were found to be within the allowable limits of the selected materials,confirming the structural integrity and reliability of the design.The suspension set is deemed suitable for the prescribed material and environmental conditions,suggesting potential for practical application in real-world rail systems.Originality/value–This research contributes to the design and optimization of bogie suspension systems using advanced CAD/CAE tools.It thinks that the material selection and numerical validation approach presented here can guide future designs in heavy load rail applications and potentially improve both safety and performance.展开更多
Due to the advantages of comfort and safety,high-speed trains are gradually becoming the mainstream public transport in China.Since the operating speed and mileage of high-speed trains have achieved rapid growth,it is...Due to the advantages of comfort and safety,high-speed trains are gradually becoming the mainstream public transport in China.Since the operating speed and mileage of high-speed trains have achieved rapid growth,it is more and more urgent to ensure their reliability and safety.As an important component in the bogies of highspeed trains,the health state of the bearing directly affects the operational safety of the trains.It is therefore necessary to diagnoze the faults of bearings in the bogies of high-speed trains as early as possible.In this paper,the bearing fault diagnostic methods for high-speed trains have been systematically summarized with their challenges and perspectives.First,it briefly introduces the structure of bearings in the bogies as well as the fault characteristic frequencies.Then,a brief review of the research on vibration-based signal processing methods and machine learning methods has been provided.Finally,the challenges and future developments of vibrationbased bearing fault diagnostic methods for high-speed trains have been analyzed.展开更多
An investigation of the effect of simplifying bogie regions on the aerodynamic performance of a high-speed train was carried out by studying four train models,to explore possible ways to optimise the train underbody s...An investigation of the effect of simplifying bogie regions on the aerodynamic performance of a high-speed train was carried out by studying four train models,to explore possible ways to optimise the train underbody structure,improve the underbody aerodynamic performance,and reduce the aerodynamic drag.The shear stress transport(SST)k-ωturbulence model was used to study the airflow features of the high-speed train with different bogie regions at Re=2.25×10^(6).The calculated aerodynamic drag and surface pressure were compared with the experimental benchmark of wind tunnel tests.The results show that the SST k-ωmodel presents high accuracy in predicting the flow fields around the train,and the numerical results closely agree with the experimental data.Compared with the train with simplified bogies,the aerodynamic drag of the train with a smooth surface and the train with enclosed bogie cavities/inter-carriage gaps decreases by 38.2%and 30.3%,respectively,while it increases by 10.8%for the train with cavities but no bogies.Thus,enclosing bogie cavities shows a good capability of aerodynamic drag reduction for a new generation of highspeed trains.展开更多
One of the major problems in structural fatigue life analysis is establishing structural load spectra under actual operating conditions.This study conducts theoretical research and experimental validation of quasi-sta...One of the major problems in structural fatigue life analysis is establishing structural load spectra under actual operating conditions.This study conducts theoretical research and experimental validation of quasi-static load spectra on bogie frame structures of high-speed trains.The quasistatic load series that corresponds to quasi-static deformation modes are identified according to the structural form and bearing conditions of high-speed train bogie frames.Moreover,a force-measuring frame is designed and manufactured based on the quasi-static load series.The load decoupling model of the quasi-static load series is then established via calibration tests.Quasi-static load–time histories,together with online tests and decoupling analysis,are obtained for the intermediate range of the Beijing—Shanghai dedicated passenger line.The damage consistency calibration of the quasi-static discrete load spectra is performed according to a damage consistency criterion and a genetic algorithm.The calibrated damage that corresponds with the quasi-static discrete load spectra satisfies the safety requirements of bogie frames.展开更多
This paper investigates the main scale analysis of the aerodynamic noise in the foremost bogie area by the large-eddy simulation(LES)and the Ffowcs Williams-Hawkings(FW-H)analogy.The mechanism of the aerodynamic noise...This paper investigates the main scale analysis of the aerodynamic noise in the foremost bogie area by the large-eddy simulation(LES)and the Ffowcs Williams-Hawkings(FW-H)analogy.The mechanism of the aerodynamic noise in this area has been excavated.The aerodynamic excitation results show that the bogie divides the bogie compartment into two cavities,each of which contains a large circulating flow and presents multi-peak characteristics in the frequency domain.The far-field noise results suggest that in the speed range of 200−350 km/h,the aerodynamic noise mechanism in the bogie area is the same.Cavity noise is the main noise mechanism in the foremost bogie area,and the bogie divides the bogie cabin into two cavities,thereby changing the aerodynamic noise in this area.展开更多
Load spectra research for bogie frame requires establishing the load?stress relationship on working condition, which has been omitted by the researchers. With the load?stress of the bogie frame of an intercity Electri...Load spectra research for bogie frame requires establishing the load?stress relationship on working condition, which has been omitted by the researchers. With the load?stress of the bogie frame of an intercity Electric Multiple Unit(Hereinafter referred to as EMU) as the research object, an optimization model of the load?stress transfer relationship is established. The load?stress coe cient for EMU bogie frame was calibrated in the laboratory bench and online test was arranged on Dazhou?Chengdu line. Comparison of nonlinear and linear neural networks proves that the linear transitive relation between the load and stress of the bogie frame in the operating process is highly suitable. An optimization model of the load?stress transfer coe cient is obtained. The data calculated with the modified coe cient are closer to the dynamic stress results in the actual operating process than the data calculated with the calibration coe cient. The coe cient of the modified transitive relation is una ected by operating area, empty load, heavy load, or other conditions in the operating process of the intercity EMU. The real loads in actual situations are obtained. The model of online load?stress relationship that is highly suitable for line stress calculation is finally established. The research is helpful for further damage calculation and inferring the time history signal of the load in load spectra research.展开更多
There exist three problems in the calculation of lateral vibration of the train-track time-variant system athome and abroad and the method to solve them is presented. Spatially coupling vibration analysis model of tra...There exist three problems in the calculation of lateral vibration of the train-track time-variant system athome and abroad and the method to solve them is presented. Spatially coupling vibration analysis model of train-track time-variant system is put forward. Each vehicle is modeled as a multi-body system with 26 degrees of freedomand the action of coupler is also considered. The track structure is modeled as an assembly of track elements with 30degrees of freedom, then the spatially coupling vibration matrix equation of the train-track time-variant system is es-tablished on the basis of the principle of total potential energy with stationary value and the "set-in-right-position"rule. The track vertical geometric irregularity is considered as the excitation source of the vertical vibration of thesystem, and the hunting wave of car bogie frame is taken as the excitation source of lateral vibration of the system.The spatially coupling vibration matrix equation of the system is solved by Wilson-θ direct integration method. Theapproximation of the calculated results to the spot test results demonstrates the feasibility and effectiveness of thepresented analysis method. Finally, some other vibration responses of the system are also obtained.展开更多
Inspired by the fact that bogies and bottom equipment generally contribute a great deal of aerodynamic drag to high-speed trains,this paper puts forward a simple method of mounting some small deflectors before and/or ...Inspired by the fact that bogies and bottom equipment generally contribute a great deal of aerodynamic drag to high-speed trains,this paper puts forward a simple method of mounting some small deflectors before and/or after the bogie cabins to optimize the underbody flow and reduce the aerodynamic drag of high-speed trains.The flow fields of the high-speed train models with and without bottom deflectors are numerically studied by the IDDES method.The effectiveness and further mechanism of the bottom deflectors on aerodynamic drag reduction are analyzed.It is demonstrated that the bottom deflectors could guide the underbody flow to the ground and prevent it from hitting on the bogies and bottom equipment of the train,resulting in a significant aerodynamic drag reduction effect.Moreover,the effects of different mounting locations of bottom deflectors on drag reduction are discussed as well,and an optimal mounting configuration with a drag reduction effect of up to about 12%is finally obtained.Nevertheless,the mounted deflector is also proved capable of significantly reducing the interference range of the underbody flow and reducing the slipstream of the train,which possesses a higher guarantee for the safety of railway workers and passengers waiting on the platforms.This work provides a new idea for aerodynamic drag reduction of high-speed trains,and is of great significance in energy conservation and consumption reduction.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
The current method of estimating the fatigue life of railway structures is to calculating the equivalent stress amplitude based on the measured stress data. However, the random of the measured data is not considered. ...The current method of estimating the fatigue life of railway structures is to calculating the equivalent stress amplitude based on the measured stress data. However, the random of the measured data is not considered. In this paper, a new method was established to compute the equivalent stress amplitude to evaluate the fatigue damage based on the measurable randomness, since the equivalent stress is the key parameter for assessment of structure fatigue life and load derivation. The equivalent stress amplitude of a high-speed train welded bogie frame was found to obey normal distribution under uniform operation route that verified by on-track dynamic stress data, and the proposed model is, in effect, an improved version of the mathematical model used to calculate the equivalent stress amplitude. The data of a long-term, on-track dynamic stress test program was analyzed to find that the normal distribution parameters of equivalent stress amplitude values differ across different operation route. Thus, the fatigue damage of the high-speed train welded bogie frame can be evaluated by the proposed method if the running schedule of the train is known a priori. The results also showed that the equivalent stress amplitude of the region connected to the power system is more random than in other regions of the bogie frame.展开更多
Establishing structural load spectrum under actual operating conditions is a major problem in structural fatigue life analysis. This study introduces the load measuring method for the bogie frame structure. The load-m...Establishing structural load spectrum under actual operating conditions is a major problem in structural fatigue life analysis. This study introduces the load measuring method for the bogie frame structure. The load-measuring frame based on quasi-static can measure different load systems synchronously. The t-test method is employed to evaluate the least test time of deducing the parent distribution. In order to fit the load spectrum distribution accurately, the kernel density estimation method is employed which is based on the sample characteristics. The expansion factor method is used to deduce the maximum load. The formula of standardized load spectrum derives from the deduced maximum load, the linear factor between operating condition length and cumulative frequency and the parent distribution of each load system. The damage consistency criterion is performed by solving the objective function with constraint conditions. The calibrated damage provides a suitable representation of the real damage under actual operating conditions. By processing and analyzing the load spectrum and stress spectrum data of the measured lines, it is verified that the standardized load spectrum established in this paper is superior to the European specification and the Japanese specification in evaluating the fatigue reliability of the structure.展开更多
To investigate the deposition distribution of snow particles in the bogie surfaces of a high-speed train,a snow particle deposition model,based on the critical capture velocity and the critical shear velocity,was elab...To investigate the deposition distribution of snow particles in the bogie surfaces of a high-speed train,a snow particle deposition model,based on the critical capture velocity and the critical shear velocity,was elaborated.Simulations based on the unsteady Reynolds-Averaged Navier-Stokes(RANS)approach coupled with Discrete Phase Model(DPM)were used to analyze the motion of snow particles.The results show that the cross beam of the bogie frame,the anti-snake damper,the intermediate brake clamps in the rear wheels,the traction rod and the anti-rolling torsion bar are prone to accumulate snow.The accumulation mass relating to the vertical surface in the rear region,horizontal surface in the front region and the corner area of the bogie is high.The average snow accumulation mass for each component ordered from high to low is as follow:traction rod,frame,bolster,brake clamp 2,anti-rolling torsion bar,brake clamp 1,transverse damper,axle box 2,axle box 1,air spring,anti-snake damper,tread cleaning device.The snow accumulation mass on the front components of the bogie is more significant than that relating to the rear components.Particularly,the average snow accumulation mass of rear brake clamp 2 and axle box 2 is about twice as high as that of the front brake clamp 1 and axle box 1.展开更多
基金Project(2016YFB1200404)supported by the National Key Research and Development Program of ChinaProjects(51605044,U1534210)supported by the National Science Foundation of China。
文摘This paper reviews the current status of investigation on snow accumulation on the bogies of high-speed trains(HSTs) running in snowy region. First, the background of the snow issue occurring to the HST and the contra-measures for the snow issue proposed in the past decades are provided by reviewing previous studies. Next, the methodology for investigating the snow issue developed by High-Speed Train Research Center of Central South University is introduced, including the numerical simulation research platform and the experimental devices for two-phase flow wind tunnel tests. Then, effective anti-snow flow control schemes for guiding the underbody airflow and their impact on the motion and accretion of snow in the installation region of the bogies are presented. Finally, the remaining investigating challenge for the snow issue of HST and the future research with respect to the challenge are provided from an engineering application viewpoint.
基金Supported by National Natural Science Foundation of China(Grant Nos.U1361117,51305360)PhD Programs Foundation of Ministry of Education of China(Grant No.20130184110005)+1 种基金Cultivation Program for the Excellent Doctoral Dissertation of Southwest Jiaotong UniversityGuangzhou Metro Corporation Program of China
文摘The current research of rail corrugation mainly focuses on the mechanisms of its formation and development. Compared with the root causes and development mechanisms, the wheel-rail impacts, the fatigue failure of vehicle-track parts, and the loss of ride comfort due to rail corrugation should also be taken into account. However, the influences of rail corrugation on vehicle and track vibration, and failure of vehicle and track structural parts are barely discussed in the literature. This paper presents an experimental and numerical investigation of the structural vibration of metro bogies caused by rail corrugation. Extensive experiments are conducted to investigate the effects of short-pitch rail corrugation on the vibration accelerations of metro bogies. A dynamic model of a metro vehicle coupled with a concrete track is established to study the influence of rail corrugation on the structural vibration of metro bogies. The field test results indicate that the short-pitch rail corrugation generates strong vibrations on the axle-boxes and the bogie frames, therefore, accelerates the fatigue failure of the bogie components. The numerical results show that short-pitch rail corrugation may largely reduce the fatigue life of the coil spring, and improving the damping value of the primary vertical dampers is likely to reduce the strong vibration induced by short-pitch rail corrugation. This research systematically studies the effect of rail corrugation on the vibration of metro bogies and proposes some remedies for mitigating strong vibrations of metro bogies and reducing the incidence of failure in primary coil springs, which would be helpful in developing new metro bogies and track maintenance procedures.
文摘Studies have shown that Zhuan K6 bogies can effectively reduce wheel-rail wear and consumption of heavy-duty trains and enhance vehicle vertical dynamic performance. However, in recent years, during the operation and maintenance of Zhuan K6 bogies, it has been discovered that two common operating failures of Zhuan K6 bogies need further improvement. The two major problems of wheel/rail unilateral wear, consumption and axle box rubber pads cracking and peeling, which are exposed during the operation of the Zhuan K6 bogie, are analyzed, the reasons are found and corresponding countermeasures are put forward.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFB4301103)the National Natural Science Foundation of China(Grant Nos.11988102,52402485,and U2368215)+1 种基金the China Postdoctoral Science Foundation(Grant No.2024M763362)the Youth Innovation Promotion Association of the Chinese Academy of Sciences(Grant No.Y2022009)。
文摘Clarifying the correlation of multi-level mechanical parameters of structures in complex dynamic systems is a prerequisite for determining the accruing fatigue damage.In this paper,we adopt the independent component analysis algorithm in unsupervised learning and tap the latent correlation between measured forces and stresses of high-speed train bogies.It is revealed that there exists a strong correlation between the vertical force and the stress at the junction of the transverse beam and the side frame,a site prone to fatigue.Stresses reconstructed by strongly correlated independent components account for more than 70%of the fatigue damage,which in turn supports the finding that the vertical forces are the main contribution to the fatigu e damage at the junction of the transverse beam and the side frame.This strong correlation between vertical forces and stresses effectively reduce the error in fatigue damage prediction and provide insights into fatigue life enhancement of critical structures of dynamic systems beyond high-speed trains.
基金support of the National Natural Science Foundation of China(Grants No.52322215,52388102 and U2368213).
文摘In strong wind-snow environments,the icing phenomenon in the bogie region can adversely affect the operational safety of highspeed trains.This study aims to design an ice-melting system that applies to high-speed train bogies and investigate its de-icing performance.The icing experiments with a scaled real bogie were first conducted in the icing and snowing wind tunnel at Central South University in China to obtain the icing distribution and thickness characteristics in the bogie region.Based on the results of icing experiments,a heating ice-melting system was designed,and the flat plate ice-melting experiments with different ice thicknesses were further carried out.The influence of ice-melting power,ice thickness,and the angle between the ice layer and the incoming flow on ice-melting characteristics was comprehensively analyzed.Findings indicate that ice-melting power and ice thickness are negatively and positively correlated with ice-melting time,respectively.As the angle between the ice layer and the incoming flow increases,the ice-melting time first increases and then decreases.Additionally,considering ice-melting energy consumption,lower ice-melting power results in reduced energy consumption for the same ice thickness and inclination angle.The ice-melting characteristics obtained in this study can provide valuable information and insights for the design of bogie ice-melting schemes and ice-melting energy saving for high-speed trains operating in cold regions.
基金supported by the National Key R&D Program of China(Grant No.2017YFB1201300)the National Natural Science Foundation of China(Grant No.51775453)+1 种基金the Fundamental Research Funds for the State Key Laboratory of Traction Power of Southwest Jiaotong University(Grant No.2019TPL-T09)the Fundamental Research Funds for the Central Universities(Grant No.2682019YQ04)。
文摘Size and weight limitations mean that ordinary railway vehicles with two double-axle bogies cannot deliver some extremely heavy cargo and products.Thus,a newly designed high-speed freight electric multiple unit(EMU)equipped with two bogie groups each with two double-axle bogies connected by a transition frame is an alternative means of transporting heavy products because of its greater load capacity.However,because it is still in the design stage,its dynamic performance is yet to be researched,something that is urgently required because of the more-complicated structure and more-intensive wheel-rail interactions than those of traditional high-speed railway vehicles.Therefore,to reveal the dynamic performance,this study establishes a three-dimensional dynamic model of a trailer vehicle in a high-speed freight EMU equipped with four double-axle bogies based on the classical theory of vehicle-track coupled dynamics.In this dynamic model,the vertical,horizontal,rolling,pitching,and yaw motions of the major components excited by random irregularities in the track geometry are considered fully.The results indicate that the derailment coefficient and stability index of this vehicle are both at excellent levels for the simulated conditions.The wheel unloading ratio appears to be larger but still within the safety range when the vehicle runs in a straight line,but it is close to or can even exceed the limit value when the vehicle runs at 400 km/h on a specified curved line.
基金the National Key R&D Program of China(Grant No.2022YFB4301303)the Major Scientific Research Project of CRRC Qingdao Sifang Co.,Ltd.(Grant No.SF/JS-Xu Zi-2024–439).
文摘Digital twin is one of the key technologies driving the digitalization and intelligence of railway transportation equipment.The development of enabling technologies such as big data,industrial internet of things,and artificial intelligence has facilitated the deep integration of digital twin technology with railway transportation,promoting the high-quality development of the railway transportation industry.This paper studies the design,manufacturing,operation,and maintenance scenarios and requirements of high-speed train sets.Based on the current status of the application and development trends of digital twin technology,it proposes the overall architecture and functional architecture of a digital train for high-speed train sets.The paper also presents the engineering implementation of key high-speed train set bogie systems,providing valuable information for the future construction of digital trains for high-speed train sets.
文摘Purpose–This paper aims to offer a novel viewpoint for improving performance and reliability by developing and optimizing suspension components in a Y25 bogie through material optimization based on wheel–rail interactions under variable load and track conditions.Design/methodology/approach–The suspension system,a critical component ensuring adaptation to road and load conditions in all vehicle types,is especially vital in heavy freight and passenger trains.In this context,the suspension set of the Y25 bogie–commonly used in T€urkiye and Europe–was modelled using CATIAV5,and stress analyses have been performed by way of ANSYS using the finite element analysis(FEA)method.E300-520-M cast steel was selected for the bogie frame,while two different spring steels,61SiCr7 and 51CrV4,were considered for the suspension springs.The modeled system was subjected to numerical analysis under loading conditions.The resulting stresses and displacements were compared with the mechanical properties of the selected materials to validate the design.Findings–The results demonstrate that the mechanical strength and deformation characteristics of the suspension components vary according to the applied external loads.The stress and displacement responses of the system were found to be within the allowable limits of the selected materials,confirming the structural integrity and reliability of the design.The suspension set is deemed suitable for the prescribed material and environmental conditions,suggesting potential for practical application in real-world rail systems.Originality/value–This research contributes to the design and optimization of bogie suspension systems using advanced CAD/CAE tools.It thinks that the material selection and numerical validation approach presented here can guide future designs in heavy load rail applications and potentially improve both safety and performance.
基金supported by the National Natural Science Foundation of China(52375078).
文摘Due to the advantages of comfort and safety,high-speed trains are gradually becoming the mainstream public transport in China.Since the operating speed and mileage of high-speed trains have achieved rapid growth,it is more and more urgent to ensure their reliability and safety.As an important component in the bogies of highspeed trains,the health state of the bearing directly affects the operational safety of the trains.It is therefore necessary to diagnoze the faults of bearings in the bogies of high-speed trains as early as possible.In this paper,the bearing fault diagnostic methods for high-speed trains have been systematically summarized with their challenges and perspectives.First,it briefly introduces the structure of bearings in the bogies as well as the fault characteristic frequencies.Then,a brief review of the research on vibration-based signal processing methods and machine learning methods has been provided.Finally,the challenges and future developments of vibrationbased bearing fault diagnostic methods for high-speed trains have been analyzed.
基金Project(2020YFF0304103-03) supported by the National Key Research and Development Program of ChinaProject(2020JJ4737) supported by the Natural Science Foundation of Hunan Province,China+1 种基金Project (202045014) supported by the Central University Financial Funds,ChinaProject(P2019J023) supported by the Science and Technology Research Program of China National Railway Group Co.,Ltd。
文摘An investigation of the effect of simplifying bogie regions on the aerodynamic performance of a high-speed train was carried out by studying four train models,to explore possible ways to optimise the train underbody structure,improve the underbody aerodynamic performance,and reduce the aerodynamic drag.The shear stress transport(SST)k-ωturbulence model was used to study the airflow features of the high-speed train with different bogie regions at Re=2.25×10^(6).The calculated aerodynamic drag and surface pressure were compared with the experimental benchmark of wind tunnel tests.The results show that the SST k-ωmodel presents high accuracy in predicting the flow fields around the train,and the numerical results closely agree with the experimental data.Compared with the train with simplified bogies,the aerodynamic drag of the train with a smooth surface and the train with enclosed bogie cavities/inter-carriage gaps decreases by 38.2%and 30.3%,respectively,while it increases by 10.8%for the train with cavities but no bogies.Thus,enclosing bogie cavities shows a good capability of aerodynamic drag reduction for a new generation of highspeed trains.
基金supported by the National Natural Science Foundation of China(U1134201)partly supported by the National High Technology Research and Development Program of China(0912JJ0104-DL00-H-HZ-001-20100105)
文摘One of the major problems in structural fatigue life analysis is establishing structural load spectra under actual operating conditions.This study conducts theoretical research and experimental validation of quasi-static load spectra on bogie frame structures of high-speed trains.The quasistatic load series that corresponds to quasi-static deformation modes are identified according to the structural form and bearing conditions of high-speed train bogie frames.Moreover,a force-measuring frame is designed and manufactured based on the quasi-static load series.The load decoupling model of the quasi-static load series is then established via calibration tests.Quasi-static load–time histories,together with online tests and decoupling analysis,are obtained for the intermediate range of the Beijing—Shanghai dedicated passenger line.The damage consistency calibration of the quasi-static discrete load spectra is performed according to a damage consistency criterion and a genetic algorithm.The calibrated damage that corresponds with the quasi-static discrete load spectra satisfies the safety requirements of bogie frames.
基金Project(2017YFB1201103)supported by the National Key Research and Development Plan of ChinaProject(2019zzts540)supported by the Graduate Student Independent Innovation Project of Central South University,China。
文摘This paper investigates the main scale analysis of the aerodynamic noise in the foremost bogie area by the large-eddy simulation(LES)and the Ffowcs Williams-Hawkings(FW-H)analogy.The mechanism of the aerodynamic noise in this area has been excavated.The aerodynamic excitation results show that the bogie divides the bogie compartment into two cavities,each of which contains a large circulating flow and presents multi-peak characteristics in the frequency domain.The far-field noise results suggest that in the speed range of 200−350 km/h,the aerodynamic noise mechanism in the bogie area is the same.Cavity noise is the main noise mechanism in the foremost bogie area,and the bogie divides the bogie cabin into two cavities,thereby changing the aerodynamic noise in this area.
基金Supported by National Natural Science Foundation of China(Grant No.U1134201)National Key Research and Development Program of China(Grant No.2016YFB1200404-08)National Key Research and Development Program of China(Grant No.2016YFB1200505-11)
文摘Load spectra research for bogie frame requires establishing the load?stress relationship on working condition, which has been omitted by the researchers. With the load?stress of the bogie frame of an intercity Electric Multiple Unit(Hereinafter referred to as EMU) as the research object, an optimization model of the load?stress transfer relationship is established. The load?stress coe cient for EMU bogie frame was calibrated in the laboratory bench and online test was arranged on Dazhou?Chengdu line. Comparison of nonlinear and linear neural networks proves that the linear transitive relation between the load and stress of the bogie frame in the operating process is highly suitable. An optimization model of the load?stress transfer coe cient is obtained. The data calculated with the modified coe cient are closer to the dynamic stress results in the actual operating process than the data calculated with the calibration coe cient. The coe cient of the modified transitive relation is una ected by operating area, empty load, heavy load, or other conditions in the operating process of the intercity EMU. The real loads in actual situations are obtained. The model of online load?stress relationship that is highly suitable for line stress calculation is finally established. The research is helpful for further damage calculation and inferring the time history signal of the load in load spectra research.
基金Project (50078006) supported by the National Natural Science Foundation of China Project (2001G029) supported by the Foundation of the Science and Technology Section of the Railway Bureau
文摘There exist three problems in the calculation of lateral vibration of the train-track time-variant system athome and abroad and the method to solve them is presented. Spatially coupling vibration analysis model of train-track time-variant system is put forward. Each vehicle is modeled as a multi-body system with 26 degrees of freedomand the action of coupler is also considered. The track structure is modeled as an assembly of track elements with 30degrees of freedom, then the spatially coupling vibration matrix equation of the train-track time-variant system is es-tablished on the basis of the principle of total potential energy with stationary value and the "set-in-right-position"rule. The track vertical geometric irregularity is considered as the excitation source of the vertical vibration of thesystem, and the hunting wave of car bogie frame is taken as the excitation source of lateral vibration of the system.The spatially coupling vibration matrix equation of the system is solved by Wilson-θ direct integration method. Theapproximation of the calculated results to the spot test results demonstrates the feasibility and effectiveness of thepresented analysis method. Finally, some other vibration responses of the system are also obtained.
基金supported by the National Key Research&Development Projects(Grant No.2017YFB0202801)the Strategic Priority Research Program of the Chinese Academy of Sciences(class B)(Grant No.XDB22020000)Research project of Chinese Academy of Sciences(Grant No.XXH13506-204).
文摘Inspired by the fact that bogies and bottom equipment generally contribute a great deal of aerodynamic drag to high-speed trains,this paper puts forward a simple method of mounting some small deflectors before and/or after the bogie cabins to optimize the underbody flow and reduce the aerodynamic drag of high-speed trains.The flow fields of the high-speed train models with and without bottom deflectors are numerically studied by the IDDES method.The effectiveness and further mechanism of the bottom deflectors on aerodynamic drag reduction are analyzed.It is demonstrated that the bottom deflectors could guide the underbody flow to the ground and prevent it from hitting on the bogies and bottom equipment of the train,resulting in a significant aerodynamic drag reduction effect.Moreover,the effects of different mounting locations of bottom deflectors on drag reduction are discussed as well,and an optimal mounting configuration with a drag reduction effect of up to about 12%is finally obtained.Nevertheless,the mounted deflector is also proved capable of significantly reducing the interference range of the underbody flow and reducing the slipstream of the train,which possesses a higher guarantee for the safety of railway workers and passengers waiting on the platforms.This work provides a new idea for aerodynamic drag reduction of high-speed trains,and is of great significance in energy conservation and consumption reduction.
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Supported by National Key Research and Development Program of China(Grant No.2018YFB1201704)National Natural Science Foundation of China(Major Program,Grant No.11790281)
文摘The current method of estimating the fatigue life of railway structures is to calculating the equivalent stress amplitude based on the measured stress data. However, the random of the measured data is not considered. In this paper, a new method was established to compute the equivalent stress amplitude to evaluate the fatigue damage based on the measurable randomness, since the equivalent stress is the key parameter for assessment of structure fatigue life and load derivation. The equivalent stress amplitude of a high-speed train welded bogie frame was found to obey normal distribution under uniform operation route that verified by on-track dynamic stress data, and the proposed model is, in effect, an improved version of the mathematical model used to calculate the equivalent stress amplitude. The data of a long-term, on-track dynamic stress test program was analyzed to find that the normal distribution parameters of equivalent stress amplitude values differ across different operation route. Thus, the fatigue damage of the high-speed train welded bogie frame can be evaluated by the proposed method if the running schedule of the train is known a priori. The results also showed that the equivalent stress amplitude of the region connected to the power system is more random than in other regions of the bogie frame.
基金This work was supported by the National Natural Science Foundation of China (Grant 51565013).
文摘Establishing structural load spectrum under actual operating conditions is a major problem in structural fatigue life analysis. This study introduces the load measuring method for the bogie frame structure. The load-measuring frame based on quasi-static can measure different load systems synchronously. The t-test method is employed to evaluate the least test time of deducing the parent distribution. In order to fit the load spectrum distribution accurately, the kernel density estimation method is employed which is based on the sample characteristics. The expansion factor method is used to deduce the maximum load. The formula of standardized load spectrum derives from the deduced maximum load, the linear factor between operating condition length and cumulative frequency and the parent distribution of each load system. The damage consistency criterion is performed by solving the objective function with constraint conditions. The calibrated damage provides a suitable representation of the real damage under actual operating conditions. By processing and analyzing the load spectrum and stress spectrum data of the measured lines, it is verified that the standardized load spectrum established in this paper is superior to the European specification and the Japanese specification in evaluating the fatigue reliability of the structure.
基金supported by the National Key Research and Development Program of China[Grant No.2016YFB1200402].
文摘To investigate the deposition distribution of snow particles in the bogie surfaces of a high-speed train,a snow particle deposition model,based on the critical capture velocity and the critical shear velocity,was elaborated.Simulations based on the unsteady Reynolds-Averaged Navier-Stokes(RANS)approach coupled with Discrete Phase Model(DPM)were used to analyze the motion of snow particles.The results show that the cross beam of the bogie frame,the anti-snake damper,the intermediate brake clamps in the rear wheels,the traction rod and the anti-rolling torsion bar are prone to accumulate snow.The accumulation mass relating to the vertical surface in the rear region,horizontal surface in the front region and the corner area of the bogie is high.The average snow accumulation mass for each component ordered from high to low is as follow:traction rod,frame,bolster,brake clamp 2,anti-rolling torsion bar,brake clamp 1,transverse damper,axle box 2,axle box 1,air spring,anti-snake damper,tread cleaning device.The snow accumulation mass on the front components of the bogie is more significant than that relating to the rear components.Particularly,the average snow accumulation mass of rear brake clamp 2 and axle box 2 is about twice as high as that of the front brake clamp 1 and axle box 1.
