交通运输工程学报

Finite element analysis of infinitely long beam resting on continuous viscoelastic foundation subjected to moving loads

LOU Ping, CENG Qing-yuan

Abstract: The beam, foundation and moving loads were considered as a system, and the system was separated into a number of finite elements.Hermitian cubic interpolation function were utilized as the bending shape functions of the two-node beam element.The element stiffness matrix, mass matrix, damping matrix, and vector of element nodal forces could be obtained by the principle of total potential energy with stationary value in elastic system dynamics. The vibration equations of the system were established. The equations were solved by Wilson θ-method, and the displacement time histories of the beam at mid-point were found. Several numerical examples were presented, and the influences of the viscoelastic characteristic of foundation and the bending stiffness of beam on dynamic responses of beam were analyzed.Calculation results show that the increase either of spring stiffness, or of damping coefficient of foundation or of the bending stiffness of beam each leads to the decrease of dynamic responses of beam.More>

2003, 3(2): 1-6.

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Influence of track parameter on welded turnout combination system

XU Qing-yuan, ZHOU Xiao-lin, CHEN Xiu-fang

Abstract: A mechanical model and its software based on the finite element principle were presented, the additional longitudinal force and displacement of the welded turnout combination system were discussed. With an example, the influences of track parameters on rail displacement and longitudinal force of the combination system and single welded turnout were calculated, and the results were analyzed.The results show that the ballast resistance has a stronger influence on the welded turnout combination system than that of the single welded turnout, the influence of fastener resistance and the gap limit of spacer pieces is almost the same; the fastener resistance has a little more but the gap limit of spacer pieces has a little less influence on the welded turnout combination system than that of the single welded turnout.More>

2003, 3(2): 7-10.

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Probabilistic mechanical properties of LZ50 axle steel for railway vehicles

ZHAO Yong-xiang, HUANG Yu-zhong, GAO Qing

Abstract: Experimental study on the probabilistic mechanical properties was performed on the LZ50 axle steel for railway vehicles.The unified approach for determining appropriate statistical models of the limited fatigue reliability data was developed to analyze the present test data.The six commonly used distributions, namely three parameter Weibull, two parameter Weibull, normal, lognormal, extreme maximum value, and extreme minimum value, were compared in fits of the data from the three considerations of goodness-of-fit, consistency of failure mechanism and safety in tail region predictions.From the viewpoint of safety, the extreme minimum value distribution was selected as an optimal model of the data.A method based on this distribution was proposed for the estimation of mechanical properties under given reliability and confidence levels.The method has been well used for the estimation of probabilistic parameters of the mechanical properties of the present material.More>

2003, 3(2): 11-17.

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Influence of joint's position and rigidity on precast box structure's internal force

LIU Hui-min, LI Zhi-ye, PEI Jun

Abstract: Taking a subway project as an example, a precast double-scan box structure was divided into five parts by using elastic double-dimension finite-element-method, those five parts included top-board, bottom-board and side-wall. The position and rigidity of the joints of those five parts have a great influence on the structure's internal force. The calculation results show that the joint's rigidity can affect the max positive moment of side-wall, the max negative moment and max positive moment of top-board; the joint's position also have influence on the max positive moment and max negative moment of top-board and side-wall; the joint's position should be located on side-wall where its moment is negative.More>

2003, 3(2): 18-21.

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Effect of vestibule diaphragm device on train dynamic performance

LIU Hong-you, WEI Xiao-dong, CENG Jing, WANG Yong

Abstract: The modelling of vestibule diaphragm was discussed. Based on the dynamic model of a single passenger car, a train dynamic model with three passenger cars was derived. By solving the differential equation groups to describe the train system, a series of simulation results about hunting motion stability, dynamic negotiation and ride comfort were worked out. The results show that the hunting motion of the train is due to the last bogie of the last car; the negotiation ability gets worse with the increasing of curving speed and the decreasing of curve radius; the ride comfort of the middle car is better than that of the head car and the tail car; the ride comfort of the train with tightlock vestibule diaphragm is the worst. It is suggested that the cushioning device should be added to the train with tightlock vestibule diaphragms.More>

2003, 3(2): 22-26.

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Fault diagnosis using wavelet packet and neural network in tilting control system of tilting train

WU Hao-zhong, WANG Kai-wen

Abstract: With the view of fault characteristics of tilting control system, this paper put forward a fault diagnosis approach employing a combination of wavelet packet and neural network.The method using wavelet packet decomposition and signal reconstruction was proposed to extract fault information from vibration signal obtained from testing jig of tilting train. By analyzing the energy of signal in full spectrum bands, the symptom that representes fault was inputted to a feed forward neural network trained by Levenberg-Marquardt optimization, which progress was very fast comparing with the improved gradient descent algorithm.The trained feed forward neural network can report the typical faults of tilting control system.Trial and research show that the method is practicable for fault diagnosis in tilting control system of reality tilting train.More>

2003, 3(2): 27-30.

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Effects of Weibull shape coefficient on ship's fatigue strength examination

DU Jia-li, YANG Yan-sheng, ZHENG Yun-feng

Abstract: Weibull shape coefficient k that is decided by ship's length and wave height is very important for studying ship's fatigue strength.Using the coefficient k, an example ship's fatigue life was calculated.It is pointed out that the calculated results have a great error compared with actul case.To reduce the error and calculate fatigue life accurately, the uniform function of coefficient k based on accumulated damage model must be developed according to ship's actul case.More>

2003, 3(2): 31-33, 87.

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Review on ship motion control

YANG Yan-sheng

Abstract: Some problems remaining unsolved in the area of ship motion control were analyzed. It was pointed that there were three problems, i.e., the first is that uncertainty always exists in the mathematical model used for designing controller, which has not been given a full attention yet; the second is that non-linearity is not included in the model when designing the controller; the last is that the actuator dynamics is not considered when designing the controller. By use of robust control and robust adaptive control theorem, several strategies that can be used to solve above problems were presented. The performance of proposed methods is illustrated with simulation results.More>

2003, 3(2): 34-39.

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Atomization characteristics comparison between diesel and LPG/diesel dual fuel

CAO Jian-ming, WU Tao, CHENG Qian, QI Dong-hui, BIAN Yao-zhang

Abstract: The comparison was analyzed by using high resolving power digital camera.Resultsshow that with LPG mixed ratio increasing, fuel droplet mean-diameters of the sprays decrease, the curve of fuel droplet size number distribution moves toward smaller diameters, and the small-size droplet number increases, spray quality goes well, and engine smoke reduces accordingly; large-size droplet diameters almost have no change, but small-size droplet diameters decrease, and relative size range and dispersion boundary of droplets increase; with penetrated distance of spray increasing, diesel droplet sizes increase, droplet sizes number distribution of the mixed fuel moves toward smaller diameters, and droplet diameters of cumulate volume increase. Both relative size range and dispersion boundary of fuel droplets have a decrease tendency; the volume distribution of fuel droplets goes to uniform gradually within larger-size range, because penetrated distance is large, spray shot distance always equal to the maximum distance that fuel can touch combustion chamber wall.More>

2003, 3(2): 40-44.

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Combustion characteristics of LPG fueled vehicle

XIE Xiao-min, MA Zhi-yi, LIU Sheng-quan

Abstract: The work diagrams in different speeds and loads were measured, and the main parameters such as pressure, rise rate of pressure, heat release quantity and heat release rate were analyzed. The results show that there are great differences between LPG and gasoline on the combustion characteristics; the combustion velocity of LPG is slower, and the combustion duration is longer than gasoline; the combustion of LPG is imperfect when load is light, but it is improved with load increasing.More>

2003, 3(2): 45-47.

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Optimization of highway profile based on genetic algorithms

XU Jin-liang, WANG Hai-jun, YANG Shao-wei

Abstract: This paper put forward a new optimization method for highway profile with genetic algorithm, which could be used to search the optimal solution in a feasible zone. It built a feasible zone according to the vertical section initial solution, and use genetic algorithms to choose the optimal solution in the feasible zone by developing chromosome concerns with the real one after another correspondence designed between the variables, to evaluae the probably solution in the feasible zone with an evaluation function(degree of suiting). The application shows that this method is capable of searching the entire solution space in order to find the global optimum; it is effective and feasible to road optimization design.More>

2003, 3(2): 48-52.

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Expressway pavement power spectral density

WANG Xin-ming, WANG Bing-gang

Abstract: With the development of pavement testing equipment, especially with the usage of laser equipment, it is possible to analyze pavement power spectral density (PPSD) exactly.Based on the analysis of testing data of long term pavement performance, it is concluded that PPSD is a good tool to analyze the pavement performance and auto-pavement dynamic loading. The limitation of ISO standard was also discussed, and a better pavement classification method with PPSD area was promoted.More>

2003, 3(2): 53-56.

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Scheme design technique of urban traffic management planning

WANG Wei

Abstract: The management tactics of urban traffic management were presented from traffic demand management and traffic system management, including priority development tactics, controlling development tactics, forbidding trip tactics, economic lever tactics under traffic demand management mode and node traffic management tactics, link traffic management tactics, region traffic management tactics under traffic system management mode. The content of scheme design of traffic management planning was put forward from urban traffic demand management, urban traffic system management and guarantee system of urban traffic order.More>

2003, 3(2): 57-60.

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Traffic flow modelling for jam developing procedure on expressway

WU Zheng

Abstract: The traffic flow modelling was established by shock wave simulation method. It is showed that a shock wave speed distribution in red light period at a plane intersection satisfies a normal assumption, as well as Poisson assumption. Based on completely jammed model, the wave speed increases as an exponential function of the traffic flow quantity. Traffic behavior parameter value may change 0 02~0 30 across the interrupted surface. The non-completely jammed model can calculate a control traffic quantity at upstream entrance of a bottleneck. 4 tabs, 8 refs.More>

2003, 3(2): 61-64.

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Logistics distribution center allocation model and elicitation algorithm

ZHANG Pei-lin, WEI Qiao-yun

Abstract: Based on the calculation of transport cost and operation variable cost, the model was developed. The solution of this model can be got through two steps. The linear function can be resolved by table-working; the nolinear function can be soluted by elicitation algorithm. With this model, the logistics distribution center allocation will be decided scientifically. This method was compared with other ones, the comparison results show that this method is more reasonable than other's.More>

2003, 3(2): 65-68.

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Incentive model and mechanism for legal person of highway construction project

LU Yi, WANG Kang-chen, ZHANG Jing-wen

Abstract: With Game Theory, the interests and behaviers of legal person and operator were analyzed. The incentive model of operator was developed to unify the interests of operator and legal person, so as to excite the operator's activities and realize legal person's interests on the condition of unsymmetrical information. The preject's quality can be assured.More>

2003, 3(2): 69-74.

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Conflict resolution in free flight with linear programming

JIN Xue-mei, HAN Song-chen, SUN Fan-rong

Abstract: Aircrafts can not get closer to each other than a given safety distance in order to avoid their conflicts. Two different schemes were designed: the one only change flying velocity; the other only change flying angle. For passengers' comfort, the changes should be minimized. The linear formula respectly for the two kinds of schemes were deduced to find out the optimum resolution methods, an example shows that this method is feasible.More>

2003, 3(2): 75-79.

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Further research of airport runway capacity evaluation

JIANG Bing, HU Ming-hua, TIAN Yong, HUANG Wei-fang

Abstract: From the view of air traffic controller, a definition of runway capacity was given, the factors that affect the capacity were analyzed. Arrival and departure capacity evaluation models were established, and the ways to calculate the runway capacity under various conditions were also provided. Based on the actual circumstance of Beijing Capital International Airport, an airport runway capacity evaluation system was developed. The simulation result proves the practicability of the evaluation model.More>

2003, 3(2): 80-83.

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Optimization method for organization of local wagon flow with district

SHI Feng, MO Hui-hui, LI Xin-hua, QIN Jin

Abstract: Rational organization of location wagon flow with district is an importation guarantee of improving railway organization and operation efficiency. The factor affecting organization of wagon flow was analyzed, and the cost of organization of local wagon flow with district was rationally described. An optimization model was established based on minimization of assembly wagon-hours, stopping wagon-hours and quantities of stopping. An optimized algorithm was presented to solve the model. The practical application shows the calculation operates efficiently, and the wagon flow organization project is rational.More>

2003, 3(2): 84-87.

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Theoretical and positive study on freight forwarder's connotation

HUANG You-heng, HAN Rui-han

Abstract: In order to unify the essential meaning of freight forwarders, according to the freight forwarding industry's present situation, the today definition of freight forwarders was put forward after inducing the relevant representative definitions from authoritative organizations and law in internal. Their service scope for consignee, consigner, and shipper was analyzed, their explanation in relevant law issued by Chinese Ministry of Foreign Trade and Economic was presented. Their industry attribute from dependency, commerciality, legality, extensive and complexity was studied, their conduct attribute and their legal status were discussed. The law on freight forwarding in China must be established as fast as possible in order to standard and manage entirely all the freight forwarding industry after joining into WTO. 9 refs.More>

2003, 3(2): 88-92.

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Quantitative effect of urban road to economic growth

CHEN Kuan-min, MA Chao-qun

Abstract: Urban road plays an important role in social and economic development for a city. Based on C-D production function, a production function model in which urban road as an input factor was developed. Through this model, the benefit of urban road can be reflected by GDP, so the quantitative distribution of urban road to social and economic development can be calculated. 2 tab, 5 refs.More>

2003, 3(2): 93-95.

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Tactics for standardizing freights forwarders operations at road transportation market

ZHAO Jian-you, XU Hong-feng, ZHENG Ming-ming

Abstract: According to the operation flow of road container transportation, the illicit behaviour of freight forwarders in China was analyzed. It was pointed out that there are those problems, such as controlling transport price, not paying on time, reporting cargo weights falsely, and so on. The government and transport society must take measures commonly to standardize their operation.More>

2003, 3(2): 96-99.

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Freeway ramp control algorithm based on neurofuzzy networks

CHEN De-wang, WANG Fei-yue, CHEN Long

Abstract: The mathematical model for the ramp control was developed. Based on this model, the fuzzy control was combined with neural network to realize the intelligent control. The simulation for this algorithm was carried out. The results show that this algorithm is always effective; it can maintain the mainline traffic flow desity in a desired value and restrain the length of queue at the on-ramp; it is better than the classic feedback algorithm ALINEA.More>

2003, 3(2): 100-105.

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Urban arterial road coordinate control based on genetic algorithm

CHANG Yun-tao, PENG Guo-xiong

Abstract: The typical problems of traditional algorithm for urban arterial road coordinate control was pointed out. The real departure-arrival model at intersection was analyzed. A new method based on genitic algorithm was developed. An example shows that the new method is better than traditional one, it can accurately describe the actul traffic flow to give a good basis for the control.More>

2003, 3(2): 106-112.

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Technique realization for trailing sight line in simulated vehicle driving

CHENG Jian-chuan, HAN Yang, YE Dan

Abstract: The geometrical model of the position of driver's eyes in simulated driving was built based on geometrical characteristics of roads, and the concept for trailing sight line was introduced.A simple and feasible idea was offered to finish trailing sight line in three-dimensional simulated vehicle driving based on OpenGL and Windows system functions.An operational table for simulated vehicle driving was designed based on the previous idea.More>

2003, 3(2): 113-116.

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Fuzzy logic control and simulation of urban traffic intersections group

LI Yan, FAN Xiao-ping

Abstract: This paper presented a fuzzy logic controller and made a comparison of its performance with other controllers. The fuzzy rules was established by gathering the traffic flow information from the detectors placed in different intersections, and the green phase and the phase sequences at an intersection were obtained to control its traffic signals and cooperated with its neighbors. Simulation results show that the presented controller can adapt to the conditions of traffic flow well, and decrease the average delay time at multi-intersections.More>

2003, 3(2): 117-119.

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Identification for road accident-prone locations

LIU Zhi-qiang, GONG Zhen, CAI Dong

Abstract: The methods for analyzing accident-prone locations were described. The model for its examining was developed. The database for its identifying was developed according to Chinese traffic flow characteristics. With the database, the identification can be carried out rapidly.More>

2003, 3(2): 120-123.

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Abstract writing criterion of science and technology paper

ZHAO Zhi-hong, SUN Shou-zeng, YANG Qi

Abstract: The abstract writing of science and technology paper is usually unspecific, inexact and incomplete, so the readers can not get enough information form abstract. This paper analysed abstract writing criterion and demands of internal-overseas famous index systems. By the means of comparison and analogism, it is concluded that canonical abstract includes specific object, method, result and conclusion; its sentences must be accurate and exact; constructure must be precise, and logic must be strong. The analysis results show that standardized abstract can increase the received opportunity of science and technology paper by internal-overseas famous index system.More>

2003, 3(2): 124-126.

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2003 Vol. 3, No. 2

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