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Prediction of high-speed train induced ground vibration based on train-track-ground system model

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Earthquake Engineering and Engineering Vibration 2010年第4期9卷 545-554页

作者： zhai wanming He Zhenxing Song Xiaolin Train and Track Research Institute Traction Power State Key Laboratory Southwest Jiaotong University Chengdu 610031 China

The development of analysis on train-induced ground vibration is briefly summarized. A train-track- ground integrated dynamic model is introduced in the paper to predict the ground vibration induced by high-speed trains. Representative dynamic responses of the train-track-ground system predicted by the model are presented. Some major results measured from two field tests on the ground vibration induced by two high-speed trains are reported. Numerical prediction with the proposed train-track-ground model is validated by the high-speed train running experiments. Research results show that the wheel/rail dynamic interaction caused by track irregularities has a significant influence on the ground acceleration and little influence on the ground displacement. The main frequencies of the ground vibration induced by high-speed trains are usually below 80 Hz. Compared with the ballasted track, the ballastless track structure can produce much larger train-induced ground vibration at frequencies above 40 Hz. The vertical ground vibration is much larger than the lateral and longitudinal components.

关键词： high-speed railway ground vibration dynamic model simulation field experiment

Dynamics modeling and electromechanical coupling characteristics analysis of cage induction motors

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Science China(Technological Sciences) 2024年第3期67卷 709-724页

作者： ZHOU ZiWei CHEN ZaiGang zhai wanming State Key Laboratory of Rail Transit Vehicle System Southwest Jiaotong UniversityChengdu 610031China

Induction motors, as typical electromechanical energy conversion devices, have received limited attention in previous studies on electromechanical coupling vibrations, precise modeling, and the use of electromechanical coupling effects for fault diagnosis and condition assessment in motor drive systems. This study proposes a comprehensive model of cage induction motors that integrates the multiple coupled circuit model with a rotor-bearing dynamics model. The model accounts for the linear increase in the magnetomotive force across the slot and incorporates the skidding characteristics of bearings in the rotor-bearing system. By calculating the time-varying mutual inductance parameters based on the air-gap distribution in the vibration environment, the electromechanical coupling vibration of the cage motor is investigated. Furthermore, this study examines the electromechanical coupling vibration characteristics influenced by various factors, including bearing clearances, radial loads, and the vertical excitation frequencies of the stators. The results show that the proposed model improves the excitation inputs for the electrical and mechanical systems of the motor compared with conventional models. Increased bearing clearance and radial load affect the current and torque similarly but have opposite effects on the slip ratio. This study provides a deeper understanding of electromechanical coupling mechanisms and facilitates the use of such phenomena for fault diagnosis and condition assessment in motor-driven systems.

关键词： cage induction motors rotor-bearing dynamics mutual inductance electromechanical testing current signal analysis

Improved analytical model for mesh stiffness calculation of cracked helical gear considering interactions between neighboring teeth

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Science China(Technological Sciences) 2023年第3期66卷 706-720页

作者： NING JieYu CHEN ZaiGang zhai wanming State Key Laboratory of Traction Power Southwest Jiaotong UniversityChengdu 610031China

As one of the most typical fault forms of the helical gear,the crack will change the dynamic excitation and further affect the dynamic behaviors of the transmission *** to the complicated structure of the helical gears,the coupling effect between the neighboring loaded teeth is usually ignored in the mesh stiffness calculation,making it considerably overestimated especially in the case of the crack *** improved mesh stiffness calculation method of helical gear with spatial crack is proposed to make up this *** interactions between the loaded neighboring teeth induced by the gear body flexibility were considered to improve the calculation accuracy and ***,the load distribution law for the engaged cracked tooth along the tooth width and profile can be *** results indicated that the mesh stiffness of the multi-tooth engagement calculation using this model could be further improved compared with the traditional ***,the effects of the helix angle,crack depth,and crack propagation length on the mesh stiffness and load distribution were investigated using the proposed method.

关键词： mesh stiffness helical gear structural coupling effect slice method spatial crack

Preface to special issue on plenary presentations of Second International Conference on Rail Transportation

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Railway Engineering Science 2022年第3期30卷 263-264页

作者： wanming zhai Southwest Jiaotong University Chengdu 610031China

The Second International Conference on Rail Transportation(ICRT),initiated and hosted by Southwest Jiaotong University,completed its agenda after two days of academic reports and seminars,and came to a successful end on 6 July 2021,in Chengdu,*** conference chairman was Professor wanming zhai from Southwest Jiaotong *** conference received tremendous support from multiple co-sponsors including National Natural Science Foundation of China,Transportation&Development Institute of ASCE,National Innovation Center of High Speed Train of China,University of Illinois at Urbana-Champaign,Tongji University,Delft University of Technology,China Academy of Railway Sciences,Royal Institute of Technology(KTH),Central South University,Politecnico di Milano,Central Queensland University,Beijing Jiaotong University and University of Technology Sydney.

关键词： Sydney initiated Southwest

Mesh excitations of spur gear considering strong correlation among tooth contact parameters,contact force,and tooth profile deviations

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Science China(Technological Sciences) 2023年第9期66卷 2500-2516页

作者： LI ZhengFa CHEN ZaiGang zhai wanming State Key Laboratory of Traction Power Southwest Jiaotong UniversityChengdu 610031China

Gear mesh excitations are widely concerned in the dynamic studies of the gear transmission ***,intentional and unintentional tooth profile deviations often occur in *** present,the established calculation models of gear mesh excitations consider tooth profile deviations as displacement ***,gear mesh excitations calculated by such models have reduced stability compared with the actual ***,in this study,an improved analytical model of gear mesh excitations with tooth profile deviations is *** established model considers tooth profile deviations,extended tooth contact,and the structure coupling effect of the gear body *** importantly,the model considers the strong correlation among tooth contact parameters,contact force,and tooth profile deviations to better reflect the actual gear mesh.A calculation flowchart with a simple calculation method of contact forces is also proposed to calculate the gear mesh ***,the effects of tooth profile deviations on gear mesh excitations are *** results show that the effects of tooth profile deviations on tooth contact position,the direction of contact force,and equivalent basic circle radii should be considered in the calculation of gear mesh excitations because of smaller system transmission errors,larger double-teeth meshing area,and slighter extended tooth *** profile deviations also cause jumps in tooth contact position and time-varying mesh ***,our findings show that the proposed model can be used to calculate the gear mesh excitations more accurately when the tooth profile deviates greatly.

关键词： mesh stiffness extended tooth contact structural coupling effect tooth contact stability analysis

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Vehicle–track–tunnel dynamic interaction:a finite/infinite element modelling method

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Railway Engineering Science 2021年第2期29卷 109-126页

作者： Lei Xu wanming zhai School of Civil Engineering Department of Railway EngineeringCentral South UniversityChangsha410075China Train and Track Research Institute State Key Laboratory of Traction PowerSouthwest Jiaotong UniversityChengdu610031China

The aim of this study is to develop coupled matrix formulations to characterize the dynamic interaction between the vehicle,track,and *** vehicle–track coupled system is established in light of vehicle–track coupled dynamics *** physical characteristics and mechanical behavior of tunnel segments and rings are modeled by the finite element method,while the soil layers of the vehicle–track–tunnel(VTT)system are modeled as an assemblage of 3-D mapping infinite elements by satisfying the boundary conditions at the infinite *** novelty,the tunnel components,such as rings and segments,have been coupled to the vehicle–track systems using a matrix coupling method for finite *** responses of sub-systems included in the VTT interaction are obtained simultaneously to guarantee the solution *** relieve the computer storage and save the CPU time for the large-scale VTT dynamics system with high degrees of freedoms,a cyclic calculation method is *** from model validations,the necessity of considering the tunnel substructures such as rings and segments is *** addition,the maximum number of elements in the tunnel segment is confirmed by numerical simulations.

关键词： Vehicle-track-tunnel interaction Railway tunnel Finite elements Infinite elements Dynamic modelling

Letter from the editor-in-chief

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Railway Engineering Science 2020年第1期28卷 1-2页

作者： wanming zhai Train and Track Research Institute State Key Laboratory of Traction PowerSouthwest Jiaotong UniversityChengdu 610031China

I am delighted to announce the launch of Railway Engineering Science,an international,peer-reviewed and free open-access journal which is renamed from Journal of Modern Transportation but focused on a narrower scope,publishing original research articles and comprehensive reviews related to fundamental engineering science and emerging technologies in various rail transit *** transit is traditional while still fascinatingly *** came into being around two centuries ago,while glowing with a new look in recent decades and still exciting in *** example,China has built the world’s largest high-speed railway(HSR)network of over 35,000 km,more than two-thirds of the world’s total HSR mileage,by the end of *** new lines are also planned and under construction.I am excited about the progress made by China that HSR network connects more than 550 cities and serves billions of people each year.

关键词： editor network journal

Train–track coupled dynamics analysis:system spatial variation on geometry,physics and mechanics

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Railway Engineering Science 2020年第1期28卷 36-53页

作者： Lei Xu wanming zhai School of Civil Engineering Department of Railway EngineeringCentral South UniversityChangsha 410075China Train and Track Research Institute State Key Laboratory of Traction PowerSouthwest Jiaotong UniversityChengdu 610031China

This paper aims to clarify the influence of system spatial variability on train–track interaction from perspectives of stochastic analysis and *** the spatial randomness of system properties in geometry,physics and mechanics,the primary work is therefore simulating the uncertainties realistically,representatively and *** regard to the track irregularity simulation,a model is newly developed to obtain random sample sets of track irregularities by transforming its power spectral density function into the equivalent track quality index for representation based on the discrete Parseval theorem,where the correlation between various types of track irregularities is accounted *** statistically clarify the uncertainty of track properties in physics and mechanics in space,a model combining discrete element method and finite element method is developed to obtain the spatially varied track parametric characteristics,*** stiffness and density,through which the highly expensive experiments in situ can be *** a train–track stochastic analysis model is formulated by integrating the system uncertainties into the dynamics *** examples have validated the accuracy and efficiency of this model and illustrated the effects of system spatial variability on train–track vibrations comprehensively.

关键词： Railway engineering Stochastic dynamic analysis Train-track interaction Vehicle-track coupled dynamics Track irregularities Longitudinal inhomogeneity

A numerical study on tread wear and fatigue damage of railway wheels subjected to anti-slip control

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Friction 2023年第8期11卷 1470-1492页

作者： Yunfan YANG Liang LING Jiacheng WANG wanming zhai State Key Laboratory of Traction Power Southwest Jiaotong UniversityChengdu 610031China

Tread wear and rolling contact fatigue (RCF) damage propagated on railway wheels are the two extremely important focal points as they can tremendously deteriorate wheel/rail interactions and hunting stability and destroy wheel surface materials, and subsequently, cut down the lifetime of the wheels. The on-board anti-slip controllers are of essence aiming to hold back the striking slipping of the powered wheelsets under low-adhesion wheel/rail conditions. This paper intends to investigate the impact of anti-slip control on wheel tread wear and fatigue damage under diverse wheel/rail friction conditions. To this end, a prediction model for wheel wear and fatigue damage evolution on account of a comprehensive vehicle–track interaction model is extended, where the wheel/rail non-Hertzian contact algorithm is used. Furthermore, the effect of frictional wear on the fatigue damage at wheel surface is considered. The simulation results indicate that the wheel/rail contact is full-slip under the low-adhesion conditions with braking effort. The wear amount under the low-adhesion conditions is observably higher than that under the dry condition. It is further suggested that the wheel tread is prone to suffering more serious wear and fatigue damage issues with a higher anti-slip control threshold compared to that with a lower one.

关键词： anti-slip control wheel/rail non-Hertzian contact adhesion condition wheel tread wear fatigue damage