Axle box bearings are critical components of high-speed trains.Localized defects,such as pitting and spalling,on raceways or rollers pose significant threats to the operational safety of railway vehicles.In this work,...Axle box bearings are critical components of high-speed trains.Localized defects,such as pitting and spalling,on raceways or rollers pose significant threats to the operational safety of railway vehicles.In this work,a novel bearing-flexible axle boxvehicle coupling model is established to explore the vibration characteristics of axle box bearings with irregular localized defects.First,based on the contact and kinematic relationship between rollers and raceways,the three-dimensional(3D)bearing force elements are analyzed and formulated.Second,the established model and a flexible axle box are integrated into the vehicle,and the responses of the normal and faulty bearings under the combined excitations of wheel roughness and track irregularities are simulated.Third,the simulation results are verified through a rolling-vibrating test bench for full-scale wheelsets of high-speed trains.The comparisons of the fault-induced repetitive transients in the time-domain and the fault characteristic frequencies in the envelope spectra demonstrate the efficiency of the proposed model.Finally,based on the flexible axle box model,a sensitivity analysis of the accelerometer placements to the bearing faults is carried out,and the optimal one is identified based on both the time-domain and frequency-domain signal-to-noise ratios(SNRs)for engineering applications.展开更多
Axle box bearings serve as crucial components within the transmission system of high-speed trains.Their failure can directly impact the operational safety of these trains.Accurately determining the dynamic load experi...Axle box bearings serve as crucial components within the transmission system of high-speed trains.Their failure can directly impact the operational safety of these trains.Accurately determining the dynamic load experienced by bearings during the operation of high-speed trains can provide valuable boundary inputs for the study of bearing fatigue life and service performance,thereby holding significant engineering implications.In this study,we propose a high-speed train axle box bearing load estimation method(FMCC-DKF).This method is founded on the Kalman filtering technique of the Maximum Correntropy Criterion(MCC)and employs dummy measurement technology to enhance the stability of estimated loads.We develop a kernel size update algorithm to address the challenges associated with obtaining the key parameter,kernel size of MCC.Comparative analysis of the vertical and lateral loads of the axle box bearing obtained using FMCC-DKF,DKF,and AMCC-DKF,under both measurement noise-free and non-Gaussian noise conditions,is conducted to demonstrate the superiority of the proposed estimation method.The results indicate that the proposed FMCC-DKF method exhibits high estimation accuracy under both measurement noise-free and non-Gaussian noise interference,and maintains its high estimation accuracy despite changes in train speed.The proposed load estimation method demonstrates reliable performance within the low-frequency domain below 70 Hz.展开更多
The wheel diameter difference would worsen the dynamic performance and affect the safety of the rail vehicle.Therefore,it is necessary to detect wheel diameter difference while the train is operating.However,several e...The wheel diameter difference would worsen the dynamic performance and affect the safety of the rail vehicle.Therefore,it is necessary to detect wheel diameter difference while the train is operating.However,several existing detection methods can’t accurately detect and diagnose the wheel diameter difference under highspeed running environment.In this study,a new method of detecting wheel diameter difference was proposed for high speed rail vehicle.The wheel diameter difference would be diagnosed by the amplitude and frequency of vibration impact on the axle box.Firstly,the dynamic model with varying wheel diameters was established in SIMPACK,and LMA tread was used in high-speed rail vehicles.Then,the simulation results of rail vehicle dynamic performance were compared under different wheel diameter differences.After that,the relationship between axle box vibration and wheel diameter difference was used to demonstrate the feasibility of this detection technology.Finally,comparing and analyzing the simulation results of vibration obtained by matching treads with different wheel diameters,it shows that by increasing the wheel diameter difference,the longitudinal and lateral impacts on axle boxes increase asymmetrically,and the amplitude and the frequency become more evident.Therefore,this paper presents a technical scheme of online measuring wheel diameter difference by monitoring the vibration of the axle box.展开更多
As an important component of the running gear of high-speed trains,axle box bearings can cause lubricating grease failure and damage to bearing components under continuous high-temperature operation,which will affect ...As an important component of the running gear of high-speed trains,axle box bearings can cause lubricating grease failure and damage to bearing components under continuous high-temperature operation,which will affect the normal operation of highspeed trains.Therefore,bearing temperature is one of the key parameters to be monitored in the online monitoring system for trains.Based on the thermal network method,this paper establishes a thermal network model for the axle box bearing,considering the radial thermal deformation of the double-row tapered roller bearing components caused by the oil film characteristics and the temperature variations of the lubricating grease.A thermo-mechanical coupling model for the grease-lubricated double-row tapered roller axle box bearing of high-speed trains with track irregularity excitation is established.The correctness of the model is verified using the test bench data,and the temperature of the bearing at different rotational speeds,loads,fault sizes,and ambient temperatures are investigated.展开更多
The China comprehensive inspection train(CIT)is designed for evaluating railway infrastructure to ensure safe railway operations.The CIT integrates an array of inspection devices,capable of simultaneously assessing ra...The China comprehensive inspection train(CIT)is designed for evaluating railway infrastructure to ensure safe railway operations.The CIT integrates an array of inspection devices,capable of simultaneously assessing railway health condition parameters.The CIT450,representing the second generation,can reach a top speed of 450 km/h with inspection on the infrastructure.This paper begins by outlining the global evolution of inspection trains.It then focuses on the critical technologies underlying the CIT450,which include:(1)real-time inspection data acquisition with spatial and temporal synchronization;(2)intelligent fusion and centralized management of multi-source inspection data,enabling remote supervision of the inspection process;(3)technologies in inspecting track,train–track interaction,catenary,signalling systems,and train operating environment;and(4)AI-driven analysis and correlation of inspection data.The future developmental directions for comprehensive inspection trains are discussed finally.The CIT450’s approach to real-time railway health monitoring can enrich traditional inspection means,operational,and maintenance methods by enhancing inspection efficiency and automating railway maintenance.展开更多
High-speed trains often use temperature sensors to monitor the motion state of bearings.However,the temperature of bearings can be affected by factors such as weather and faults.Therefore,it is necessary to analyze in...High-speed trains often use temperature sensors to monitor the motion state of bearings.However,the temperature of bearings can be affected by factors such as weather and faults.Therefore,it is necessary to analyze in detail the relationship between the bearing temperature and influencing factors.In this study,a dynamics model of the axle box bearing of high-speed trains is established.The model can obtain the contact force between the rollers and raceway and its change law when the bearing contains outer-ring,inner-ring,and rolling-element faults.Based on the model,a thermal network method is introduced to study the temperature field distribution of the axle box bearings of high-speed trains.In this model,the heat generation,conduction,and dispersion of the isothermal nodes can be solved.The results show that the temperature of the contact point between the outer-ring raceway and rolling-elements is the highest.The relationships between the node temperature and the speed,fault type,and fault size are analyzed,finding that the higher the speed,the higher the node temperature.Under different fault types,the node temperature first increases and then decreases as the fault size increases.The effectiveness of the model is demonstrated using the actual temperature data of a high-speed train.This study proposes a thermal network model that can predict the temperature of each component of the bearings on a high-speed train under various speed and fault conditions.展开更多
By modifying friction to the desired level,the application of friction modifiers(FMs)has been considered as a promising emerging tool in the railway engineering for increasing braking/traction force in poor adhesion c...By modifying friction to the desired level,the application of friction modifiers(FMs)has been considered as a promising emerging tool in the railway engineering for increasing braking/traction force in poor adhesion conditions and mitigating wheel/rail interface deterioration,energy consumption,vibration and noise.Understanding the effectiveness of FMs in wheel–rail dynamic interactions is crucial to their proper applications in practice,which has,however,not been well explained.This study experimentally investigates the effects of two types of top-of-rail FM,i.e.FM-A and FM-B,and their application dosages on wheel–rail dynamic interactions with a range of angles of attack(AoAs)using an innovative well-controlled V-track test rig.The tested FMs have been used to provide intermediate friction for wear and noise reduction.The effectiveness of the FMs is assessed in terms of the wheel–rail adhesion characteristics and friction rolling induced axle box acceleration(ABA).This study provides the following new insights into the study of FM:the applications of the tested FMs can both reduce the wheel–rail adhesion level and change the negative friction characteristic to positive;stick–slip can be generated in the V-Track and eliminated by FM-A but intensified by FM-B,depending on the dosage of the FMs applied;the negative friction characteristic is not a must for stick–slip;the increase in ABA with AoA is insignificant until stick–slip occurs and the ABA can thus be influenced by the applications of FM.展开更多
The feasibility of monitoring the dipped rail joint defects has been theoretically investigated by simulating a locomotive-mounted acceleration system negoti- ating several types of dipped rail defects. Initially, a c...The feasibility of monitoring the dipped rail joint defects has been theoretically investigated by simulating a locomotive-mounted acceleration system negoti- ating several types of dipped rail defects. Initially, a comprehensive locomotive-track model was developed using the multi-body dynamics approach. In this model, the locomotive car-body, bogie frames, wheelsets and driving motors are considered as rigid bodies; track modelling was also taken into account. A quantitative relationship between the characteristics （peak-peak values） of the axle box accelerations and the rail defects was determined through simulations. Therefore, the proposed approach, which combines defect analysis and comparisons with theoretical results, will enhance the ability for long-term monitoring and assessment of track systems and provides more informed preventative track maintenance strategies.展开更多
基金supported by the National Natural Science Foundation of China(Nos.12372056,12032017,12393783)the S&T Program of Hebei of China(No.24465001D)。
文摘Axle box bearings are critical components of high-speed trains.Localized defects,such as pitting and spalling,on raceways or rollers pose significant threats to the operational safety of railway vehicles.In this work,a novel bearing-flexible axle boxvehicle coupling model is established to explore the vibration characteristics of axle box bearings with irregular localized defects.First,based on the contact and kinematic relationship between rollers and raceways,the three-dimensional(3D)bearing force elements are analyzed and formulated.Second,the established model and a flexible axle box are integrated into the vehicle,and the responses of the normal and faulty bearings under the combined excitations of wheel roughness and track irregularities are simulated.Third,the simulation results are verified through a rolling-vibrating test bench for full-scale wheelsets of high-speed trains.The comparisons of the fault-induced repetitive transients in the time-domain and the fault characteristic frequencies in the envelope spectra demonstrate the efficiency of the proposed model.Finally,based on the flexible axle box model,a sensitivity analysis of the accelerometer placements to the bearing faults is carried out,and the optimal one is identified based on both the time-domain and frequency-domain signal-to-noise ratios(SNRs)for engineering applications.
基金National Key R&D Program of China(Grant numbers 2022YFB4301201-11,2022YFB4301203-05)National Natural Science Foundation of China(Grant number 52202464).
文摘Axle box bearings serve as crucial components within the transmission system of high-speed trains.Their failure can directly impact the operational safety of these trains.Accurately determining the dynamic load experienced by bearings during the operation of high-speed trains can provide valuable boundary inputs for the study of bearing fatigue life and service performance,thereby holding significant engineering implications.In this study,we propose a high-speed train axle box bearing load estimation method(FMCC-DKF).This method is founded on the Kalman filtering technique of the Maximum Correntropy Criterion(MCC)and employs dummy measurement technology to enhance the stability of estimated loads.We develop a kernel size update algorithm to address the challenges associated with obtaining the key parameter,kernel size of MCC.Comparative analysis of the vertical and lateral loads of the axle box bearing obtained using FMCC-DKF,DKF,and AMCC-DKF,under both measurement noise-free and non-Gaussian noise conditions,is conducted to demonstrate the superiority of the proposed estimation method.The results indicate that the proposed FMCC-DKF method exhibits high estimation accuracy under both measurement noise-free and non-Gaussian noise interference,and maintains its high estimation accuracy despite changes in train speed.The proposed load estimation method demonstrates reliable performance within the low-frequency domain below 70 Hz.
基金the Local Capacity Building Project of Shanghai Municipal Science and Technology Commission(No.17090503500)the Young Teachers Training Funding Scheme of Shanghai Colleges and Universities(No.ZZZZyyx16023)。
文摘The wheel diameter difference would worsen the dynamic performance and affect the safety of the rail vehicle.Therefore,it is necessary to detect wheel diameter difference while the train is operating.However,several existing detection methods can’t accurately detect and diagnose the wheel diameter difference under highspeed running environment.In this study,a new method of detecting wheel diameter difference was proposed for high speed rail vehicle.The wheel diameter difference would be diagnosed by the amplitude and frequency of vibration impact on the axle box.Firstly,the dynamic model with varying wheel diameters was established in SIMPACK,and LMA tread was used in high-speed rail vehicles.Then,the simulation results of rail vehicle dynamic performance were compared under different wheel diameter differences.After that,the relationship between axle box vibration and wheel diameter difference was used to demonstrate the feasibility of this detection technology.Finally,comparing and analyzing the simulation results of vibration obtained by matching treads with different wheel diameters,it shows that by increasing the wheel diameter difference,the longitudinal and lateral impacts on axle boxes increase asymmetrically,and the amplitude and the frequency become more evident.Therefore,this paper presents a technical scheme of online measuring wheel diameter difference by monitoring the vibration of the axle box.
基金Project supported by the National Natural Science Foundation of China(Nos.12393780,12032017,and 12002221)the Key Scientific Research Projects of China Railway Group(No.N2021J032)+2 种基金the College Education Scientific Research Project of Hebei Province of China(No.JZX2024006)the S&T Program of Hebei Province of China(No.21567622H)the National Scholarship Council of China。
文摘As an important component of the running gear of high-speed trains,axle box bearings can cause lubricating grease failure and damage to bearing components under continuous high-temperature operation,which will affect the normal operation of highspeed trains.Therefore,bearing temperature is one of the key parameters to be monitored in the online monitoring system for trains.Based on the thermal network method,this paper establishes a thermal network model for the axle box bearing,considering the radial thermal deformation of the double-row tapered roller bearing components caused by the oil film characteristics and the temperature variations of the lubricating grease.A thermo-mechanical coupling model for the grease-lubricated double-row tapered roller axle box bearing of high-speed trains with track irregularity excitation is established.The correctness of the model is verified using the test bench data,and the temperature of the bearing at different rotational speeds,loads,fault sizes,and ambient temperatures are investigated.
基金supported by the National Natural Science Foundation of China(Grant No.52272427)the Technology Research and Development Program of China National Railway Group(Grant No.K2021T015)Development Plan of China Academy of Railway Sciences Corporation Ltd.(Grant No.2022YJ256)。
文摘The China comprehensive inspection train(CIT)is designed for evaluating railway infrastructure to ensure safe railway operations.The CIT integrates an array of inspection devices,capable of simultaneously assessing railway health condition parameters.The CIT450,representing the second generation,can reach a top speed of 450 km/h with inspection on the infrastructure.This paper begins by outlining the global evolution of inspection trains.It then focuses on the critical technologies underlying the CIT450,which include:(1)real-time inspection data acquisition with spatial and temporal synchronization;(2)intelligent fusion and centralized management of multi-source inspection data,enabling remote supervision of the inspection process;(3)technologies in inspecting track,train–track interaction,catenary,signalling systems,and train operating environment;and(4)AI-driven analysis and correlation of inspection data.The future developmental directions for comprehensive inspection trains are discussed finally.The CIT450’s approach to real-time railway health monitoring can enrich traditional inspection means,operational,and maintenance methods by enhancing inspection efficiency and automating railway maintenance.
基金National Key R&D Program(Grant No.2020YFB2007700),National Natural Science Foundation of China(Grant Nos.11790282,12032017,12002221 and 11872256)S&T Program of Hebei(Grant No.20310803D)+1 种基金Natural Science Foundation of Hebei Province(Grant No.A2020210028)State Foundation for Studying Abroad.
文摘High-speed trains often use temperature sensors to monitor the motion state of bearings.However,the temperature of bearings can be affected by factors such as weather and faults.Therefore,it is necessary to analyze in detail the relationship between the bearing temperature and influencing factors.In this study,a dynamics model of the axle box bearing of high-speed trains is established.The model can obtain the contact force between the rollers and raceway and its change law when the bearing contains outer-ring,inner-ring,and rolling-element faults.Based on the model,a thermal network method is introduced to study the temperature field distribution of the axle box bearings of high-speed trains.In this model,the heat generation,conduction,and dispersion of the isothermal nodes can be solved.The results show that the temperature of the contact point between the outer-ring raceway and rolling-elements is the highest.The relationships between the node temperature and the speed,fault type,and fault size are analyzed,finding that the higher the speed,the higher the node temperature.Under different fault types,the node temperature first increases and then decreases as the fault size increases.The effectiveness of the model is demonstrated using the actual temperature data of a high-speed train.This study proposes a thermal network model that can predict the temperature of each component of the bearings on a high-speed train under various speed and fault conditions.
基金supported by European Union’s Horizon 2020 research and innovation programme in the project In2Track2 under Grant agreement No. 826255
文摘By modifying friction to the desired level,the application of friction modifiers(FMs)has been considered as a promising emerging tool in the railway engineering for increasing braking/traction force in poor adhesion conditions and mitigating wheel/rail interface deterioration,energy consumption,vibration and noise.Understanding the effectiveness of FMs in wheel–rail dynamic interactions is crucial to their proper applications in practice,which has,however,not been well explained.This study experimentally investigates the effects of two types of top-of-rail FM,i.e.FM-A and FM-B,and their application dosages on wheel–rail dynamic interactions with a range of angles of attack(AoAs)using an innovative well-controlled V-track test rig.The tested FMs have been used to provide intermediate friction for wear and noise reduction.The effectiveness of the FMs is assessed in terms of the wheel–rail adhesion characteristics and friction rolling induced axle box acceleration(ABA).This study provides the following new insights into the study of FM:the applications of the tested FMs can both reduce the wheel–rail adhesion level and change the negative friction characteristic to positive;stick–slip can be generated in the V-Track and eliminated by FM-A but intensified by FM-B,depending on the dosage of the FMs applied;the negative friction characteristic is not a must for stick–slip;the increase in ABA with AoA is insignificant until stick–slip occurs and the ABA can thus be influenced by the applications of FM.
基金the support of the Centre for Railway Engineering, Central Queensland Universitythe support from State Key Laboratory of Traction Power, Southwest Jiaotong University in the Open Projects: TPL1504, ‘Study on heavy haul train and coupler system dynamics’
文摘The feasibility of monitoring the dipped rail joint defects has been theoretically investigated by simulating a locomotive-mounted acceleration system negoti- ating several types of dipped rail defects. Initially, a comprehensive locomotive-track model was developed using the multi-body dynamics approach. In this model, the locomotive car-body, bogie frames, wheelsets and driving motors are considered as rigid bodies; track modelling was also taken into account. A quantitative relationship between the characteristics （peak-peak values） of the axle box accelerations and the rail defects was determined through simulations. Therefore, the proposed approach, which combines defect analysis and comparisons with theoretical results, will enhance the ability for long-term monitoring and assessment of track systems and provides more informed preventative track maintenance strategies.
