1.

Effect of rail corrugation on vertical dynamics of railway vehicle coupled with a track





Email author&prev_q=Xuesong JinEmail author" target="_blank">Xuesong JinEmail author Kaiyun Wang Zefeng Wen Weihua Zhang《Acta Mechanica Sinica》,2005年第21卷第1期


The effect of rail corrugation on the vertical dynamics of railway vehicle coupled with a curved track is investigated in detail with a numerical method when a wheelset is steadily curving. In the calculation of rail corrugation we consider the combination of Kalker‘s rolling contact theory modified, a model of material loss on rail running surface, and a dynamics model of railway vehicle coupled with a curved track. In the establishment of the dynamic model, for simplicity, one fourth of the freight car without lateral motions,namely a wheelset and the equivalent one fourth freight car body above it, is considered. The Euler beam is used to model the rails and the track structure under the rails is replaced with equivalent springs, dampers and mass bodies. The numerical results show the great influence of the rail corrugation on the vibration of the parts of the vehicle and the track, and the some characters of rail corrugation in development.

2.

Study on the subgrade deformation under highspeed train loading and water–soil interaction





Jian Han GuoTang Zhao XiaoZhen Sheng XueSong Jin《Acta Mechanica Sinica》,2016年第32卷第2期


It is important to study the subgrade characteristics of highspeed railways in consideration of the water–soil coupling dynamic problem,especially when highspeed trains operate in rainy regions.This study develops a nonlinear water–soil interaction dynamic model of slab track coupling with subgrade under highspeed train loading based on vehicle–track coupling dynamics.By using this model,the basic dynamic characteristics,including water–soil interaction and without water induced by the highspeed train loading,are studied.The main factorsthe permeability coefficien and the porosityinfluencin the subgrade deformation are investigated.The developed model can characterize the soil dynamic behaviour more realistically,especially when considering the influenc of waterrich soil.

3.

Development of a simulation model for dynamic derailment analysis of highspeed trains





Liang Ling XinBiao Xiao XueSong Jin《Acta Mechanica Sinica》,2014年第6期


The running safety of highspeed trains has become a major concern of the current railway research with the rapid development of highspeed railways around the world.The basic safety requirement is to prevent the derailment.The root causes of the dynamic derailment of highspeed trains operating in severe environments are not easy to identify using the field tests or laboratory experiments.Numerical simulation using an advanced train–track interaction model is a highly efficient and lowcost approach to investigate the dynamic derailment behavior and mechanism of highspeed trains.This paper presents a threedimensional dynamic model of a highspeed train coupled with a ballast track for dynamic derailment analysis.The model considers a train composed of multiple vehicles and the nonlinear intervehicle connections.The ballast track model consists of rails,fastenings,sleepers,ballasts,and roadbed,which are modeled by Euler beams,nonlinear springdamper elements,equivalent ballast bodies,and continuous viscoelastic elements,in which the modal superposition method was used to reduce the order of the partial differential equations of Euler beams.The commonly used derailment safety assessment criteria around the world are embedded in the simulation model.The train–track model was then used to investigate the dynamic derailment responses of a highspeed train passing over a buckled track,in which the derailmentmechanism and train running posture during the dynamic derailment process were analyzed in detail.The effects of train and track modelling on dynamic derailment analysis were also discussed.The numerical results indicate that the train and track modelling options have a significant effect on the dynamic derailment analysis.The intervehicle impacts and the track flexibility and nonlinearity should be considered in the dynamic derailment simulations.

4.

Interaction of subway LIM vehicle with ballasted track in polygonal wheel wear development





Ling Li XinBiao Xiao XueSong Jin《Acta Mechanica Sinica》,2011年第27卷第2期


This paper develops a coupled dynamics model for a linear induction motor (LIM) vehicle and a subway track to investigate the influence of polygonal wheels of the vehicle on the dynamic behavior of the system. In the model, the vehicle is modeled as a multibody system with 35 degrees of freedom. A Timoshenko beam is used to model the rails which are discretely supported by sleepers. The sleepers are modeled as rigid bodies with their vertical, lateral, and rolling motions being considered. In order to simulate the vehicle running along the track, a moving sleeper support model is introduced to simulate the excitation by the discrete sleeper supporters, in which the sleepers are assumed to move backward at a constant speed that is the same as the train speed. The Hertzian contact theory and the Shen HedrickElkins’ model are utilized to deal with the normal dynamic forces and the tangential forces between wheels and rails, respectively. In order to better characterize the linear metro system (LMS), Euler beam theory based on modal superposition method is used to model LIM and RP. The vertical electric magnetic force and the lateral restoring force between the LIM and RP are also taken into consideration. The former has gapvarying nonlinear characteristics, whilst the latter is considered as a constant restoring force of 1 kN. The numerical analysis considers the effect of the excitation due to polygonal wheels on the dynamic behavior of the system at different wear stages, in which the used data regarding the polygonal wear on the wheel tread are directly measured at the subway site.

5.

Effect of wheelset flexibility on wheel–rail contact behavior and a specific coupling of wheel–rail contact to flexible wheelset





Shuoqiao Zhong Xinbiao Xiao Zefeng Wen Xuesong Jin《Acta Mechanica Sinica》,2016年第32卷第2期


The fexibility of a train's wheelset can have a large effect on vehicle–track dynamic responses in the medium to high frequency range.To investigate the effects of wheelset bending and axial deformation of the wheel web,a specifi coupling of wheel–rail contact with a fexible wheelset is presented and integrated into a conventional vehicle–track dynamic system model.Both conventional and the proposed dynamic system models are used to carry out numerical analyses on the effects of wheelset bending and axial deformation of the wheel web on wheel–rail rolling contact behaviors.Excitations with various irregularities and speeds were considered.The irregularities included measured track irregularity and harmonic irregularities with two different wavelengths.The speeds ranged from 200 to400km/h.The results show that the proposed model can characterize the effects of fexible wheelset deformation on the wheel–rail rolling contact behavior very well.

6.

Track dynamic behavior at rail welds at high speed





Guangwen Xiao·Xinbiao Xiao·Jun Guo·Zefeng Wen·Xuesong Jin State Key Laboratory of Traction Power Southwest Jiaotong University Chengdu China《Acta Mechanica Sinica》,2010年第26卷第3期


As a vehicle passing through a track with different weld irregularities, the dynamic performance of track com ponents is investigated in detail by using a coupled vehi cletrack model. In the model, the vehicle is modeled as a multibody system with 35 degrees of freedom, and a Timoshenko beam is used to model the rails which are dis cretely supported by sleepers. In the track model, the sleepers are modeled as rigid bodies accounting for their vertical, lat eral and rolling motions and assumed to move backward at a constant speed to simulate the vehicle running along the track at the same speed. In the study of the coupled vehicle and track dynamics, the Hertizian contact theory and the theory proposed by ShenHedrickElkins are, respectively, used to calculate normal and creep forces between the wheel and the rails. In the calculation of the normal forces, the coefficient of the normal contact stiffness is determined by transient contact condition of the wheel and rail surface. In the calcu lation of the creepages, the lateral, rollover motions of the rail and the fact that the relative velocity between the wheel and rail in their common normal direction is equal to zero are simultaneously taken into account. The motion equations of the vehicle and track are solved by means of an explicit integration method, in which the rail weld irregularities are modeled as local track vertical deviations described by some ideal cosine functions. The effects of the train speed, the axle load, the wavelength and depth of the irregularities, and the weld center position in a sleeper span on the wheelrail impact loading are analyzed. The numerical results obtained are greatly useful in the tolerance design of welded rail pro file irregularity caused by handgrinding after rail welding and track maintenances.

7.

Dynamic interactions of an integrated vehicle–electromagnetic energy harvester–tire system subject to uneven road excitations





Jing Tang Xing Zhe Sun Sulian Zhou Mingyi Tan《Acta Mechanica Sinica》,2017年第2期


An investigation is undertaken of an integrated mechanicalelectromagnetic coupling system consisting of a rigid vehicle with heave, roll, and pitch motions, four electromagnetic energy harvesters and four tires subject to uneven road excitations in order to improve the passengers' riding comfort and harvest the lost engine energy due to uneven roads. Following the derived mathematical formulations and the proposed solution approaches, the numerical simulations of this interaction system subject to a continuous sinusoidal road excitation and a single ramp impact are completed. The simulation results are presented as the dynamic response curves in the forms of the frequency spectrum and the time history, which reveals the complex interaction characteristics of the system for vibration reductions and energy harvesting performance. It has addressed the coupling effects on the dynamic characteristics of the integrated system caused by:(1) the natural modes and frequencies of the vehicle;(2) the vehicle rolling and pitching motions;(3) different road excitations on four wheels;(4) the time delay of a road ramp to impact both the front and rear wheels, etc., which cannot be tackled by an often used quarter vehicle model. The guidelines for engineering applications are given. The developed coupling model and the revealed concept provide a means with analysis idea to investigate the details of four energy harvester motions for electromagnetic suspension designs in order to replace the current passive vehicle isolators and to harvest the lost engine energy. Potential further research directions are suggested for readers to consider in the future.

8.

Numerical analysis of dynamic response of vehicle–bridge coupled system on longspan continuous girder bridge





《力学快报》,2016年第4期


To systematically study the vehicle–bridge coupled dynamic response and its change rule with different parameters, a vehicle model with seven degrees of freedom was built and the total potential energy of vehicle space vibration system was deduced. Considering the stimulation of road roughness, the dynamic response equation of vehicle–bridge coupled system was established in accordance with the elastic system principle of total potential energy with stationary value and the ‘‘setinrightposition' rule. On the basis of the selfcompiled Fortran program and bridge engineering, the dynamic response of longspan continuous girder bridge under vehicle load was studied. This study also included the calculation of vehicle impact coefficient, evaluation of vibration comfort, and analysis of dynamic response parameters.Results show the impact coefficient changes with lane number and is larger than the value calculated by the ‘‘general code for design of highway bridges and culverts(China)'. The Dieckmann index of bridge vibration is also related to lane number, and the vibration comfort evaluation is good in normal conditions.The relevant conclusions from parametric analyses have practical significance to dynamic design and daily operation of longspan continuous girder bridges in expressways. Safety and comfort are expected to improve significantly with further control of the vibration of vehicle–bridge system.

9.

Integration of uniform design and quantumbehaved particle swarm optimization to the robust design for a railway vehicle suspension system under different wheel conicities and wheel rolling radii





YungChang Cheng ChengKang Lee《Acta Mechanica Sinica》,2017年第33卷第5期


This paper proposes a systematic method, integrating the uniform design(UD)of experiments and quantumbehaved particle swarm optimization(QPSO),to solve the problem of a robust design for a railway vehicle suspension system. Based on the new nonlinear creep model derived from combining Hertz contact theory, Kalker's linear theory and a heuristic nonlinear creep model,the modeling and dynamic analysis of a 24 degreeoffreedom railway vehicle system were investigated.The Lyapunov indirect method was used to examine the effects of suspension parameters, wheel conicities and wheel rolling radii on critical hunting speeds.Generally,the critical hunting speeds of a vehicle system resulting from worn wheels with different wheel rolling radii are lower than those of a vehicle system having original wheels without different wheel rolling radii.Because of worn wheels, the critical hunting speed of a running railway vehicle substantially declines over the long term. For safety reasons,it is necessary to design the suspension system parameters to increase the robustness of the system and decrease the sensitive of wheel noises.By applying UD and QPSO,the nominalthebest signaltonoise ratio of the system was increased from?48.17 to?34.05 dB.The rate of improvement was 29.31%.This study has demonstrated that the integration of UD and QPSO can successfully reveal the optimal solution of suspension parameters for solving the robust design problem of a railway vehicle suspension system.

10.

Study on fluidstructure interaction in liquid oxygen feeding pipe systems using finite volume method





Xin Wei Bing Sun《Acta Mechanica Sinica》,2011年第27卷第5期


The fluidstructure interaction may occur in space launch vehicles,which would lead to bad performance of vehicles,damage equipments on vehicles,or even affect astronauts’ health.In this paper,analysis on dynamic behavior of liquid oxygen (LOX) feeding pipe system in a large scale launch vehicle is performed,with the effect of fluidstructure interaction (FSI) taken into consideration.The pipe system is simplified as a planar FSI model with Poisson coupling and junction coupling.Numerical tests on pipes between the tank and the pump are solved by the finite volume method.Results show that restrictions weaken the interaction between axial and lateral vibrations.The reasonable results regarding frequencies and modes indicate that the FSI affects substantially the dynamic analysis,and thus highlight the usefulness of the proposed model.This study would provide a reference to the pipe test,as well as facilitate further studies on oscillation suppression.

11.

Entanglement in OneDimensional Random XY Spin Chain with DzyaloshinskiiMoriya Interaction





单传家 程维文 刘堂昆 黄燕霞 李宏《中国物理快报》,2008年第25卷第3期


The impurities of exchange couplings, external magnetic fields and DzyaloshinskiiMoriya （DM） interaction considered as Gaussian distribution, and the entanglement in onedimensional random XY spin systems is investigated by the method of solving the different spinspin correlation functions and the average magnetization per spin. The entanglement dynamics at central locations of ferromagnetic and antiferromagnetic chains have been studied by varying the three impurities and the strength of DM interaction. （i） For the ferromagnetic spin chain, the weak DM interaction can improve the amount of entanglement to a large value, and the impurities have the opposite effect on the entanglement below and above critical DM interaction. （ii） For the antiferromagnetic spin chain, DM interaction can enhance the entanglement to a steady value. Our results imply that DM interaction strength, the impurity and exchange couplings （or magnetic field） play competing roles in enhancing quantum entanglement.

12.

A new coupledmap carfollowing model based on a transportation supernetwork framework





姚静 黄婧祎 陈关荣 许维胜《中国物理 B》,2013年第6期


A new carfollowing model is proposed by considering information from a number of preceding vehicles with intervehicle communication. A supernetwork architecture is first described, which has two layers： a traffic network and a communication network. The two networks interact with and depend on each other. The error dynamic system around the steady state of the model is theoretically analyzed and some nonjam criteria are derived. A simple control signal is added to the model to analyze the criteria of suppressing traffic jams. The corresponding numerical simulations confirm the correctness of the theoretical analysis. Compared with previous studies concerning coupled map models, the controlled model proposed in this paper is more reasonable and also more effective in the sense that it takes into account the formation of traffic congestion.

13.

COUPLING VIBRATION OF VEHICLEBRIDGE SYSTEM 被引次数：1





陈炎 黄小清 马友发《应用数学和力学(英文版)》,2004年第25卷第4期


By applying the sinusoidal wave mode to simulate the rugged surface of bridge deck, accounting for vehiclebridge interaction and using EulerBernoulli beam theory, a coupling vibration model of vehiclebridge system was developed. The model was solved by mode analyzing method and RungeKutta method, and the dynamic response and the resonance curve of the bridge were obtained. It is found that there are two resonance regions, one represents the main resonance while the other the minor resonance, in the resonance curve. The influence due to the rugged surface, the vibration mode of bridge, and the interaction between vehicle and bridge on vibration of the system were discussed. Numerical results show that the influence due to these parameters is so significant that the effect of roughness of the bridge deck and the mode shape of the bridge can‘ t be ignored and the vehicle velocity should be kept away from the critical speed of the vehicle_

14.

COMPREHENSIVE MATHEMATICAL MODEL OF MICROCIRCULATORY DYNAMICS (Ⅰ)——BASIC THEORY 被引次数：1





Guo Zhongsan Xiao Fan Guo Siwen Wu Yueqing Gu Leye《应用数学和力学(英文版)》,1999年第20卷第9期


Under the basis of physiological data, a nonlinear and unsteady comprehensive mathematical model of microcirculatory dynamics with distributed parameters is developed. Hemodynamics, interstitium dynamics, lymph dynamics, dynamics of protein transport, oxygen dynamics, dynamics of heat transfer, and myogenic and metabolic regulation procedures are included. The interactions between these factors were comprehensively exhibited. The influences of arteriolar vasomotion and nonlinear viscoelasticity of blood in arteriole are considered. A simplified vessel network consisting of arteriole, open and reserved capillaries, venule, initial lymphatics and arteriolevenule anastomose is adopted as the geometrical model. This kind of comprehensive mathematical model is helpful in analyzing clinical data and developing a “numerical experiment method” in microcirculation research.

15.

Thermospin effects in parallel coupled double quantum dots in the presence of the Rashba spinorbit interaction and Zeeman splitting





薛惠杰 吕天全 张红晨 尹海涛 催莲 贺泽龙《中国物理 B》,2012年第3期


The thermoelectric and the thermospin transport properties,including electrical conductivity,Seebeck coefficient,thermal conductivity,and thermoelectric figure of merit,of a parallel coupled doublequantumdot AharonovBohm interferometer are investigated by means of the Green function technique.The periodic Anderson model is used to describe the quantum dot system,the Rashba spinorbit interaction and the Zeeman splitting under a magnetic field are considered.The theoretical results show the constructive contribution of the Rashba effect and the influence of the magnetic field on the thermospin effects.We also show theoretically that material with a high figure of merit can be obtained by tuning the Zeeman splitting energy only.

16.

Scaling limits of interacting diffusions in domains





ZhenQing Chen WaiTong Louis Fan《Frontiers of Mathematics in China》,2014年第9卷第4期


We survey recent effort in establishing the hydrodynamic limits and the fluctuation limits for a class of interacting diffusions in domains. These systems are introduced to model the transport of positive and negative charges in solar cells. They are general microscopic models that can be used to describe macroscopic phenomena with coupled boundary conditions, such as the popula tion dynamics of two segregated species under competition. Proving these two types of limits represents establishing the functional law of large numbers and the functional central limit theorem, respectively, for the empirical measures of the spatial positions of the particles. We show that the hydrodynamic limit is a pair of deterministic measures whose densities solve a coupled nonlinear heat equations, while the fluctuation limit can be described by a Gaussian Markov process that solves a stochastic partial differential equation.

17.

The dynamics of onedimensional random quantum XY system with DzyaloshinskiiMoriya interaction





李银芳 孔祥木《中国物理 B》,2013年第3期


In this paper,the effects of random variables on the dynamics of the s = 1/2 XY model with the DzyaloshinskiiMoriya interaction are studied.By means of the recurrence relation method in the hightemperature limit,we calculate the spin autocorrelation functions as well as the corresponding spectral densities for the cases that the exchange couplings between spins or external magnetic fields satisfy the doubleGaussian distribution.It is found that when the standard deviation of random exchange coupling δJ(or the standard deviation of random external field δB) is small,the dynamics of the system undergoes a crossover from a collectivemode behavior to a centralpeak one.However,when δJ(or δB) is large,the crossover vanishes,and the system shows a centralpeak behavior or the most disordered one.We also analyze the cases in which the exchange couplings or the external fields satisfy the bimodal and the Gaussian distributions.Our results show that for all the cases considered,the dynamics of the above system is similar to that of the onedimensional random XY model.

18.

Influences of aerodynamic loads on hunting stability of highspeed railway vehicles and parameter studies





XiaoHui Zeng Han Wu Jiang Lai HongZhi Sheng《Acta Mechanica Sinica》,2014年第6期


The influences of steady aerodynamic loads on hunting stability of highspeed railway vehicles were investigated in this study.A mechanism is suggested to explain the change of hunting behavior due to actions of aerodynamic loads：the aerodynamic loads can change the position of vehicle system（consequently the contact relations）,the wheel/rail normal contact forces,the gravitational restoring forces/moments and the creep forces/moments.A mathematical model for hunting stability incorporating such influences was developed.A computer program capable of incorporating the effects of aerodynamic loads based on the model was written,and the critical speeds were calculated using this program.The dependences of linear and nonlinear critical speeds on suspension parameters considering aerodynamic loads were analyzed by using the orthogonal test method,the results were also compared with the situations without aerodynamic loads.It is shown that the most dominant factors a ff ecting linear and nonlinear critical speeds are different whether the aerodynamic loads considered or not.The damping of yaw damper is the most dominant influencing factor for linear critical speeds,while the damping of lateral damper is most dominant for nonlinear ones.When the influences of aerodynamic loads are considered,the linear critical speeds decrease with the rise of cross wind velocity,whereas it is not the case for the nonlinear critical speeds.The variation trends of critical speeds with suspension parameters can be significantly changed by aerodynamic loads.Combined actions of aerodynamic loads and suspension parameters also a ff ect the critical speeds.The effects of such joint action are more obvious for nonlinear critical speeds.

19.

POLE PLACEMENT CONTROLLERS FOR LINEAR TIMEDELAY SYSTEMS WITH COMMENSURATE POINT DELAYS





M.delaSen《分析论及其应用》,2004年第20卷第4期


This paper investigates the exact and approximate spectrum assignment properties associated with realizable outputfeedback poleplacement type controllers for singleinput singleoutput linear timeinvariant timedelay systems with commensurate point delays. The controller synthesis problem is discussed through the solvability of a set of coupled diophantine equations of polynomials. An extra complexity is incorporated to the above design to cancel extra unsuitable dynamics being generated when solving the above diophantine equations. Thus, the complete controller tracks any arbitrary prefixed (either finite or delaydependent) closedloop spectrum. However, if the controller is simplified by deleting the above mentioned extra complexity, then the robust stability and approximated spectrum assignment are still achievable for a certain sufficiently small amount of delayed dynamics. Finally, the approximate spectrum assignment and robust stability problems are revisited under plant disturbances if the nominal controller is maintained. In the current approach, the finite spectrum assignment is only considered as a particular case to the designer‘s choice of a (delaydependent) arbitrary spectrum assignment objective.

20.

NONLINEAR DYNAMICAL CHARACTERISTICS OF PILES UNDER HORIZONTAL VIBRATION 被引次数：2





胡育佳 程昌钧 杨骁《应用数学和力学(英文版)》,2005年第26卷第6期


The pilesoil system is regarded as a viscoelastic halfspace embedded pile. Based on the method of continuum mechanics, a nonlinear mathematical model of pilesoil interaction was establisheda coupling nonlinear boundary value problem. Under the case of horizontal vibration, the nonlinearly dynamical characteristics of pile applying the axis force were studied in horizontal direction in frequency domain. The effects of parameters, especially the axis force on the stiffness were studied in detail. The numerical results suggest that it is possible that the pile applying an axis force will lose its stability. So,the effect of the axis force on the pile is considered.
