西南交通大学学报

Lateral Stability Analysis for Rail Vehicle Dynamic Models with Uncertain Parameters

Cao Dengqing

1999, 12(3): 253-258.

[Abstract](1448)

Abstract:
Consider the rail vehicle dynamic models with uncertain parameters and nonlinear uncertainties. Using the Lyapunov stability theory and employing the special properties of matrices, a lateral stability criterion for the system is derived. The robust stability bounds obtained are not necessarily symmetric with respect to the origin in the parameter space, and can significantly enlarge the stability region for the uncertain parameters. The robust stability of a rail vehicle wheelset subjected to uncertain suspension is analyzed by using the proposed approach, and the results obtained in this paper are compared with existing ones.

Simulation of Pressure on Overline Bridge Due to High-Speed Train Passage

Lei Bo　, Liu Yingqing

1999, 12(3): 259-263.

[Abstract](1717)

Abstract:
It is necessary to predict the aerodynamic load on buildings near the track due to high-speed train passage for designing these buildings and determining their limit. In this paper, a numerical computation of pressure on overline bridge surface by a high- speed train head is carried out with 3D Panel method. Results of the computations show that on overline bridge a pressure pulse occurs while a train passes. the coefficients of the pressure pulse range from-0.135 to 0.095. The features of pressure distribution on overline bridge are discussed.

Dynamical Analysis and Improving Measures for the Bogies of Heavy Switching Locomotive

Chen Qing, Pu Dezhang

1999, 12(3): 264-268.

[Abstract](1519)

Abstract:
Normal bogies of trunk locomotives are not fitted to the switching services on the curve line with small radii. With the increasing of the axle load, this case is getting worse. The technical characteristics and the test results on the bogies of the diesel locomotives used on mountainous areas and heavy mineral fields are introduced in this paper. A dynamics analysis for a heavy switching locomotive is provided, with improving measures for the locomotive are investigated. The theoretical calculation and the field tests show that it is profitable for the curving behavior to adopt roller friction side bearers, meanwhile, some succeeded experiences of bogies should be used to develop the heavy switching locomotive.

Algebraic Method of Hopf Bifurcation of Railway Vehicle System

Wu Pingbo, ZhangJiye

1999, 12(3): 269-273.

[Abstract](1946)

Abstract:
The theories of stability and bifurcation are used to analyze the hunting bifurcation of nonlinear railway vehicle system in this paper. An algebraic criterion of the point causing Hopf bifurcation and its analysis method are given with Hurwitz determinant. By using this method, the research on the stability of passenger car is made.

Stick-Slip Vibration Analysis of Constrained Wheelset

Zhang Limin

1999, 12(3): 274-278.

[Abstract](1721)

Abstract:
Analysis of stick-slip vibration of two contact bodies is executed in detail based on the dynamics of stick-slip systems and principle of non-linear friction. A stick- slip vibration equation is established for SDOF system, and conditions which stick-slip vibrations begin to occur are deduced, the effects of drive velocity exerted on the range of slip are analyzed, and the results of numerical calculation show that there exists a linear relation between them . Based on the creep force, the possible torsion stick-slip vibration of constrained wheelset is also analyzed, pointing out the reasons of producing stick-slip vibration of wheelset in the inner side when curving and uneven frictions on the contact surfaces of the rails and wheelset.

Study of Controlling of an Electromagnet and Permanent Magnet Suspension Isolation System

Liu Shangju, Yan Ju, Chen Qiu

1999, 12(3): 279-283.

[Abstract](1607)

Abstract:
Precise instruments and devices used on aircrafts should follow low frequency motion as aircraft taking off and on normal fying; on the other hand, they should also isolate the high frequency motion caused by spurting fuel, etc. This paper studied a novel isolating method-electromagnet and permanent magnet suspension isolation. After establishing the physical and mathematicn models concerning horizontal and vertical translation freedom degree, the paper proposed a pole-placing method to design the control system. By computer simulation, it is indicated that the control system could meet the task well.

A Recursive Formulation for the Dynamic Analysis of Open Loop Tree Deferrable Multibody Systems

TangHuaping, KongXiang an

1999, 12(3): 284-289.

[Abstract](1380)

Abstract:
In this paper, a relative coordinate system is introduced to describe the motion of flexible multibody system. This coordinate system fully utilizes the property of transform matrix to reduce the nonlinear couplings between rigid and elastic motion. A recursive formulation for the dynamic analysis of open loop trees deferrable multibody systems based on the Jardon s principal is presented. The dynamic equation is assembled from outer layer to inner layer. Having used the recursive technique for dynamic equation s formulation, computer storage is much less than other methods in calculation. A numerical example is given.

A Palletising Robot Based on the DELTA Robotic Mechanism

Hua Weishi

1999, 12(3): 290-294.

[Abstract](1275)

Abstract:
A design of palletizing robot based on the DELTA robotic mechanism is presented in the paper. The robot has high rigidity, high accuracy, and low mobile mass relative to an equivalent serial robot. It is suitable to be used for rapid palletizing and transfer operating. The design could have some other potential applications. The singularities and inverse kinematic solution of the DELTA robot are discussed.

Agitation Mechanism and Its Application Research of a New-Type Punched Agitator

Liu Jing, Xiang Qun, WangNengqin

1999, 12(3): 295-299.

[Abstract](1123)

Abstract:
Based on the mixing principle, the authors analyze the agitation mechanism of a new-type punched agitator,and announce that such punched agitators with simple structure not only can improve the mixing through intensifying the eddy spread,but also reduce the power consumption by diminishing the projection area in the direction which the paddles round.Through the application research in the water system ,it is obviously shown that such punched agitators have the characteristics of simple structure,high efficiency and lower power consumption, and it can be widely applied .

Detecting Methods of Transient Faults and Permanent Faults for Multiple Line Traction Network

Gao Shibin, Chen Xiaochuan, Xu Zhigen

1999, 12(3): 300-304.

[Abstract](1304)

Abstract:
Two methods, voltage detecting method and compensated voltage detecting method, are proposed for detecting the permanent faults and transient faults of multiple line traction network. The effectiveness and sensitivity of these two methods are verified by computer simulation. The simulation results show that both of the two detecting methods are effective, and the compensated voltage detecting method is more sensitive.

Application of New Binary Model Structure in Power Electronic Circuits Simulation

Yan Jifu, Li Zhi, Xiao Tijing

1999, 12(3): 305-309.

[Abstract](1373)

Abstract:
This paper presents a new simulation method for power electronic circuits through the uses of a digital computer. Semiconductor switches are described as binary inductor models, with very low values of inductance during conduction and infinite values of inductance in other case. Also, in the paper, an approach to determine these low values of inductance is presented. The equations are established with modified nodal method, then Backward Euler integration method is employed for the solution of equations to ensure its convergence. With this method, the status of switches can be monitored efficiently, and the changes of topology structure are solved with least amount of computation. In addition, a simulation example is given,with its waveforms presented.

Research of Data Transformation and Fusion in Virtual Environment

Ding Guofu, WangJinnuo

1999, 12(3): 310-314.

[Abstract](1254)

Abstract:
Virtual Environment (VE) is a simulation environment,which fuses much information of cyber-soace to make the effect of immersion and interaction. To interact the virtual objects in VE , a series of geometric transformation should be offered .This paper studies the geometric transformation procedure,which exists in the coordinate system of VE. Especially, the research of fusing the information of the hand space and stereoscopic vision in virtual space is given.It assures the harmony of the interaction between human and the computer.

A Mimetic Statics Numeric Method on Earthquake Resistance Analysis of Shallow Buried Tunnels

Lu Helin

1999, 12(3): 315-319.

[Abstract](1500)

Abstract:
A mimetic statics numeric method on earthquake resistance analysis of shallow buried tunnels is introduced in this paper. The effects of seismic waves are regarded as equivalent static loading on surrounding rock and tunnel lining. According to the feature of the seismic waves, the effects of body waves (P,S wave) and surface wave (R wave) should be calculated separately. The calculated stresses of seismic waves are added to the stresses of static loads as the maximum stresses in tunnel lining. FEM or other numeric methods can be used in computing the structural displacement and stress both for seismic wave and static load. The introduced method has been used in the research on earthquake resistance of the tunnels in Nanning-Kunming railway project.

The Seismic Response Behavior of Long Span CFST Arch Bridge

Zheng Shixiong, Zhou Shuhua, Ding Guibao

1999, 12(3): 320-324.

[Abstract](1686)

Abstract:
A seismic response model of long span concrete filled steel tube (CFST) arch bridge is set up. Taking a bridge of 76+360+76 m span concrete filled steel tube tied arch bridge as an example, the seismic response behavior is systematically studied. The results show that in the apex of arch the response member forces are low, while response horizontal displacement is maximum, forces in the springing of main arch rib are relatively large, and the non-synchronous support motion due to the traveling seismic wave may have a significant effect on the response. They tend to increase the axial-force of arch rib and vertical displacement and decrease the horizontal displacement.

Heat Transportation in Tunnels When Train with High Temperature Passing Through

Wu Xiyong, Wang Ying, Zheng Anqi

1999, 12(3): 325-330.

[Abstract](1489)

Abstract:
Due to heat transportation, the temperature field in tunnels will change when the trains with high temperature passing through. The moving heat transportation owing to high temperature source is studied, and the temperature distribution in a tunnel is calculated in an example. The results can be used in environment improvement of tunnels and reduction of temperature effect on tunnel concrete lining.

High Density Resistivity Imaging Technique and Its Application in Prospecting Diseases of Railway Bed

Jiang Weihong, Jiang Zhenghong, Wang Bin

1999, 12(3): 331-336.

[Abstract](1594)

Abstract:
This paper introduces the elementary principle of the high density resistivity imaging method which springs up in the field of hydrology, engineering and environmental geophysical prospecting in recent year. According to the characteristics of the diseases of the railway bed, the study and application of the high density resistivity imaging technique have been carried out and a new measurement scheme and data processing-image software system are developed. By comparing the results of the finite element numerical simulation to image formation and the field measure of the typical diseases of railway bed, it shows that the new technique is accurate, effective and convenient for detecting diseases of railway bed.

Brazil Test of Rocks with Bearing Plates of Press

FengXingqiao, Cao Fuen

1999, 12(3): 337-342.

[Abstract](1255)

Abstract:
This paper presents a study on Brazil test of rocks using the bearing plates of a press. The rocks used in the study are of red-sandstone(kig) of the Jiaguan section of the cretaceous period taken from Emei, Sichuan Province. Brazil tests are conducted according to rock mechanics, and tensile and press test are also done. The theoretical analysis and the experimental results show that it is feasible and convenient to carry out Brazil test with the bearing plates of a press directly.

The Effect of Nitrogen on the Characteristic of Low-Cycle Fatigue of 316 Series Austenitic Stainless Steels

He Guoqiu, Chen Chengshu, Gao Qing

1999, 12(3): 343-348.

[Abstract](1374)

Abstract:
Tests on low-cycle fatigue under uniaxial tension-compression and multiaxial nonproportional loading of two typical strain paths and the observation on micro structures of 316L and 316LN austenitic stainless steels are made. The effect of nitrogen element on the characteristics of low-cycle fatigue under uniaxial and multiaxial nonproportional loading and micro structures of stainless steels are analyzed with emphasis. The micro mechanism of the dependence of nonproportional cyclic additional hardening and low-cycle fatigue life on the nitrogen element is studied thoroughly.

Thermodynamic Properties of the Bulk Metallic Glass

ZengXiaolan

1999, 12(3): 349-353.

[Abstract](1302)

Abstract:
By Differential Scanning Calorimetry (DSC), the transition temperatureTg and the primly crystallization temperatureTxof the metallic alloy Zr-106 are measured. Their values are 325℃and 470℃respectively. After the material is heated at the different temperature and different time lengths in the temperature interval ofTgand Tx, the microstructure of the as-received material is investigated by using X-ray diffraction and Transmission Electron Microscopy, meanwhile, a hot press test is carried out at a specific temperature of 370℃. The results show that the alloy has a large supercooled liquid region and high thermal stability against crystallization, and is excellent in heating plasticity.

A New Method of Fuzzy Comprehensive Evaluation and Its Application in Evaluating Laboratory

Pu Dezhang

1999, 12(3): 354-359.

[Abstract](1425)

Abstract:
In order to proceed comprehensive evaluation of complicated multi-factors system with fuzzness rationally, a new mathematical model is established about multi- factors and multistage fuzzy comprehensive evaluation by combining fuzzy matrix with fuzzy integral. Then a method is put forward for determining the single-factor evaluation matrix and the weight of factor, finally, a reasonable comprehensive evaluation procedure is given for laboratory. The theory and the way can widely be applied to similar multi-factors comprehensive evaluation system with fuzziness

Structure and Consistent of the Non-Parametric Kernel Density Estimation

Liu Haiyan, Zhao Lianwen

1999, 12(3): 360-364.

[Abstract](1311)

Abstract:
A kind of kernel density estimation method is discussed in non-parametric statistics for independently and identically distributed random variable of density. In this discussion, a new estimation value method is introduced; then, the method’s consistency, the stability, the optimal bandwidth, and asymptotic confidence interval of f(x)are obtained.

Study on Optimization of Through Goods Train’s Linkage at Technical Station

Zhu Jianmei

1999, 12(3): 365-368.

[Abstract](1514)

Abstract:
By analyzing the relationship between the through goods train’s linkage and the equilibriumof departure trains at technical stations, a network flow model for linking through goods train is set up.This problem can be solved by using the special algorithm for minimal cost maximum flow. Its application shows that it is effective for optimizing the through goods train s linkage and the equilibriumof the departing train at technical station.

Discussions on Network Planning of Urban Rail Transit

Wang Zhongqiang, Gao Shilian, JiangJinqi

1999, 12(3): 369-373.

[Abstract](1424)

Abstract:
To make URT network plan quantitatively rather than qualitatively, some key points about URT network planning are probed in this paper. Rational scale of network is investigated with modal analysis by means of system analysis and graphic theory. A planning methodology of initial network and its software data flow programming are proposed. Finally, the ideology of URT network planning is concluded. The discussions included in this paper are useful to planning of URT project.

Study on the Installation of Passenger Stations in Communications and Transportation Hub

Xi Qing, Huo Yamin, YeHuaizhen

1999, 12(3): 374-378.

[Abstract](1541)

Abstract:
Studying on the traffic transfer mode and on the basis of coordinating the transportation forms in hubs, a method of installation of passenger stations using the transportation corridor principle, of which concentration and dispersion is combined, is put forward.

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1999 Vol. 12, No. 3