交通运输工程学报

Development and dynamic characteristics of radial bogies

LI Fei, FU Mao-hai, HUANG Yun-hua

Abstract: Solving the conflict between curving performance and hunting stability is always a hard work for a long time in the fields of vehicle system dynamics. Using the conventional bogies can not satisfy the both requests in the same time. The radial bogie, which not only meets the request of curving performance but also improves the hunting stability effectively, can solves the conflict. The application and development of radial bogies are briefly introduced, and the principles and structures of force-steering and self-steering radial bogies are expounded. An uniform lateral dynamic model including the force-steering, self-steering and flexible primary suspension bogie is established, and their dynamic characteristics are compared by computer simulation. The analytic results show that adopting radial bogies is an effective measure, which may reduce wheel/rail wear on curve and improve stability on straight. The radial bogie is adapted to the tilting train and the passenger car that is required to improve speed in existing lines of many curves.More>

2003, 3(1): 1-6.

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Dynamics behaviors of high speed tilting car bogie

LI Xiao-yan, LI Fei, FU Mao-hai

Abstract: If the raillway is just going to possess an eminent station in transportation market, it must improve its running speed to shorten the running time of passengers and freights. Today, the improving speed of passenger cars has become an important technology policy of Chinese railway. Adopting the tilting car is an effective measure to improve speed in the existing line. The bogie is one of the key technologies of the tilting car. The characteristic of several kinds of bogies of the tilting car abroad and the basic complexion of Chinese railways is introduced. According to the feature of track and the special demands of tilting car to the bogie, a project that the primary suspension of the bogie for the tilting car is soft, is put forward, and the feasibility and necessity are analyzed. The basic structure and dynamics of the bogie for Chinese tilting cars are discussed.More>

2003, 3(1): 7-12.

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Explicit finite element method for vehicle crashworthiness

YAO Song, TIAN Hong-qi, GAO Guang-jun

Abstract: Based on the continuum mechanics, governing equations of vehicle collisions were set up and the weak form of the equilibrium equations was found. Through explicit discretization of space and time, finite element equation was obtained. By utilizing dynamic explicit integral, nodal displacements were calculated explicitly, which avoids the convergence problem caused by highly non-linear factors including material, geometry, boundary. Also the Courant stability condition for thin-shell element was discussed. The design method of crashworthy structure longitudinal compress deformation, longitudinally absorbing energy was proposed and numeric simulation on an example was carried out. The results show that the design method can realize self-structure passive safety and the explicit finite element method is an effective way for structure crashworthiness research. But it is necessary to carry out some crash tests so as to modify the numeric model and!improve simulation accuracy.More>

2003, 3(1): 13-16.

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Enveloped surface method in interference detection between opening and closing mechanism of lids of high speed train

LIU Guo-wei, ZHOU Wei

Abstract: How to check collision must be solved in the design of the opening and closing mechanism of the lids of high speed train. Traditional interference detection way is quite tedious and time-consuming, so it is not suitable for the design requirements. Therefore, a method of interference detection was presented by using envelopes surface to replace the moving part. The opening and closing mechanism of the lids is looked as a plane four bar linkage. Based on the theory of envelopes for 1-parameter family of surfaces to analyze this plane four bar linkage, the mathematical modeling of enveloped surface of the lids was deduced accurately. This method is intuitive in geometry, less digital computation needed and easily programming using computer, so it is favorable for building the CAD/CAM software of the opening and closing mechanism of the lids.More>

2003, 3(1): 17-20.

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Calculating theory of railway welded turnout based on generalized variational principle

LI Qiu-yi, CHEN Xiu-fang

Abstract: Based on existing experimental data and energy variation principle, generalized variational principle is applied to analyze railway welded turnout structures, and a new method of calculating welded turnout structures is presented. It builds a consummate calculation model, sleeper is regarded as finite long beam on continuous elastics base, and the relation between rail forces and sleeper displacements is established by analysis of sleeper forces. On the basis of supposing rail displacements function, energy of welded turnout structures is computed. By means of generalized variational methods the equilibrium equation is derived. A calculation program is worked out, the additional temperature forces and the expanding and contracting displacements of the inner rails are analyzed.More>

2003, 3(1): 21-24.

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Additional longitudinal forces transmission between bridges and continuously welded rails with small resistance fasteners

XU Qing-yuan, CHEN Xiu-fang

Abstract: To lay continuously welded rails on railway bridges, small resistance fasteners are used to be applied to reduce the mutual interaction forces between the rails and the bridges.To the ballast track, there are distinct relative displacement among the rail, sleeper and beam. However, the former mechanics model in this aspect didn't take the influence of the displacement of the sleeper into account. Thus, there are obvious discrepancy between the theory and the practice cases. A new mechanics model revealing additional longitudinal forces transmission between the continuously welded rails and the bridges, which takes the influence of the mutual relative displacement between the rail, sleeper and beam into account, is established. An example is presented and the results are compared. The results show that the calculated results of the new model are less than that of the formers, especially in the case of the flexible pier bridges. Without the consideration of the displacement of the sleeper, this model is also suited for the analysis of the additional longitudinal forces transmission between the rails and bridges of ballastless track with small resistance fasteners. The calculated results also show that compared to the ballast bridge, the ballastless bridges have a much stronger additional longitudinal forces transmission between the continuously welded rails and bridges.More>

2003, 3(1): 25-29.

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Stability of subgrade embankment on sloped weak ground

JIANG Xin, WEI Yong-xing, QIU Yan-jun

Abstract: This paper analyses the stability of subgrade embankment during construction and after completion on sloped weak ground using limit equilibrium theory. Cross-sectional factors influencing the stability behavior of embankment, such as the ground slope, the thickness of weak layer and the height of embankment, are also explored. Research results show that the minimum safety factor will decrease when the embankment height, the weak layer thickness and the ground slope increase, and there are two kinds of failure models of subgrade embankment on sloped weak ground. Furthermore, some viewpoints concerning the construction of high fills are proposed as well.More>

2003, 3(1): 30-34.

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3-D numerical analysis of influence of layer modulus on structural responses of asphalt pavements

MAO Cheng, QIU Yan-jun

Abstract: At present, influence of layer modulus on structural responses of asphalt pavements is analyzed using general Burmister theory. However, pavement responses under axle loading is three dimensional (3D) in nature. Using 3-D numerical simulation, this paper reports the impact of pavement structural module on pavement surface deflection, compressive stress and tensile stress at the bottom of surface and base respectively. The results indicate that the higher layer modulus are, the lower surface deflectiones, the higher base's module can result in great vertical compressive stress at asphalt layer, and the higher subgrade's module can result in lower tensile stress at the bottom of base. The analysis results have great value to design and construction of asphalt pavements.More>

2003, 3(1): 35-39.

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Prediction of asphalt mixtures fatigue properties using damage mechanics

GE Zhe-sheng, HUANG Xiao-ming

Abstract: A method that was used to analyze cement concrete fatigue and damage was put forward by A.Alliche and D.Francois. Using this method to calculate asphalt mixtures fatigue life, it is found that there is much differences between its result and testing result, the result is related with the parameter of forecast model, the damage evolvement of asphalt mixtures is different with that of cement concrete. The rule of asphalt mixtures damage evolvement was put forward based on a new method. Its forecast result was compared with testing result.It is shown that this method is scientific, moreover, its prediction is accurate.More>

2003, 3(1): 40-42.

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Effects of existing asphalt pavement on loading stress of ultra-thin-whitetopping pavement

MA Biao, HU Zhang-shun

Abstract: Ultra-thin-whitetopping(UTW) is a recently developed rehabilitation technique of distressed asphalt concrete pavement. For quantitatively analyzing the influence degree of the existing asphalt pavement to UTW pavement, UTW slab is regarded as surface layer, the existing asphalt layer is regarded as base course, and the layers under the base of existing asphalt pavement are regarded as the compositive ground. Using the three-dimensional isoparametric element, according to elastic three-layer model, loading stresses of UTW are calculated. On the basis of these results, the effects of asphalt thickness, thickness of slab, and general modules of ground(E c) on the stress are analyzed. The results indicate that loading stress of slab bottom varies linearly with thickness of asphalt, and the slope is relate to the modules of the ground(E s). The thickness of asphalt exceed 6 cm was favorable for serving of UTW while the slab was thin. Elastic modules of asphalt layer exceeding certain value little influenced to stress of slab bottom of pavement, and this value can be utilized to evaluate quality of existing asphalt layer.With decreasing of the elastic modules of asphalt, thickness of asphalt layer bring minus effect to the stress of slab bottom.More>

2003, 3(1): 43-46.

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Performance of multiphalte in experiments

LIU Chao-hui, LI Yu-zhi, HUANG Yun-yong

Abstract: The performance indexes of multiphalte were tested through contrast experiments and according to the performance grading(PG) indexes of SHRP, USA.Resultsshow that the multiphalte's performance reaches PG76-28 standard and meets the standard of EVA? PE modification asphalt of China.It has good high temperature stability and temperature sensibility.On the tests of mixture design and all the performance indexes of multiphalte mixture, the results suggest its high temperature stability and lower temperature performance is acceptable.More>

2003, 3(1): 47-51.

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Real-time dynamic display technology of road 3D scene

PU Hao, SONG Zhan-feng, ZHENG Shun-yi, ZHAN Zhen-yan

Abstract: The technology of real-time dynamic display is the key technology to realize road 3D visual design. This paper applied the creating algorithm of Delaunay triangulation to constructing digital terrain model and accomplished 3D modeling of road entities according to the ideal of divide and conquer. An effective view-dependent simplification algorithm for road 3D model was worked out. Benefit from the algorithm being combined with the technology of showing realistic image, the real-time dynamic browsing platform of road 3D scene was explored. The 3D browser was integrated with the system of road CAD, which realized the visualizations of both design course and design fruits.More>

2003, 3(1): 52-56.

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Optimal toll standard in Chang-ping freeway

YANG Zhao-sheng, YANG Zhi-hong, ZHAO Dan-hua

Abstract: Freeway construction in China was initiated in the late 1980s, but up to now freeway toll standard, which mainly comes from experiences, is still lack of science basis. It is a whole government action. Taking Chang-ping freeway as an example, the relation of the toll standard and traffic volume was analyzed. It is pointed out that to establish scientific toll standard must obey three conditions, the first is to encourage it to absorb more vehicles and reach the most social benefit, the secondl is that the toll income can assure maintenance expense, management cost and overhaul payout, the third is to ensure users can gain profit.According this idea, the tolling model for chang-ping freeway was developed. The results show that this model is more scientific and reasonable.More>

2003, 3(1): 57-61.

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Traffic characteristic on offset intersection

CHEN Tao, WEI Lang, CHEN Yin-san, GAO Yun-feng, WEI Jun

Abstract: The offset intersection is a special type of intersection. Making full use of the existing resource and realizing the reasonable signal control of the offset intersection could be achieved through comprehensive management in the light of the geographical situation, the traffic environment and the structure of traffic flow. Taking the offset intersection on Southern Middle Section of Xi'an city Second Circular Road, which has been running for 7 years, for example, these traffic characteristics of the offset intersection, such as traffic volume, average vehicle speed and operational delay, are investigated and analyzed. Against such problems as severe delay, high parking rate on arterial roads and low capacity on the offset intersection, the preliminary study is carried out according to traffic signal control system, traffic management, configuration of traffic sign and marking.More>

2003, 3(1): 62-67.

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Computation of logistic cost

CHENG Yao-rong, YAN Bao-jie

Abstract: It is important and significant to figure out the logistic cost. The principle and the process to figure out the logistic cost, and the relation between the logistic cost and logistic service were analyzed. It is pointed out that the logistic cost should play an important role in logistic management.More>

2003, 3(1): 68-71.

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Car-following safe distance control algorithm and implementation based on fuzzy inference

WANG Wen-qing, WANG Wu-hong, ZHONG Yong-gang, YI Sheng-ping

Abstract: Car-following is an ubiquitous traffic phenomenon. It is hard to describe drivers' behavior with precise algorithm because of its indetermination and fuzzy characteristic when controlling the vehicle. In order to assure safety of vehicle on the road, it is necessary to research the safe distance of car-following. Based on this thought, an algorithm of car-following distance control was put forward and simulated. The simulation results show that it is feasible to describe drivers' behavior with fuzzy inference, and the following vehicle can follow the leading vehicle in safe distance by fuzzy control.More>

2003, 3(1): 72-75.

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Architecture of expressway traffic control system based on multi-agent

WANG Zhen-yu, GAO Geng-jun, HUANG Wei

Abstract: The increasing of expressway traffic quantity has brought forward a higher request on expressway traffic control. The traditional traffic control methods based on precise mathematics models is complex and the effects of their application always can not reach the expectation, so developing a new control method is necessary. Multi-agent technology is a hotspot in the artificial intelligence field. One agent controls its object autonomically and initiatively. Between two agents there is a cooperation which can improve the intelligence of the whole system. This paper introduced the concept of the Multi-Agent System(MAS), and described the architecture of the expressway traffic control system based on multi-agent and the functions of modules inside agent. A brief analysis of the cooperation between agents was presented. The expressway traffic control system based on multi-agent technology, which is an intelligent traffic control system with new architecture, can overcome drawbacks of the traditional traffic control methods and can adapt well to the complexity and randomicity of expressway traffic. The key of MAS technology is the cooperation between agents. Consequently the next research should be focused on how to build an effective mechanism of cooperation between agents.More>

2003, 3(1): 76-79.

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Traffic noise forecasting model at roundabout

CHANG Yu-lin, WANG Wei

Abstract: This paper proposes the appraising point of the roundabout's traffic noise.After analyzing the roundabout's noises caused by the inlet road vehicles and round road vehiches, it sets up the equivalent traffic noise forecasting model and simplified model.These models indicate that the equivalent traffic noise of the roundabout is mainly influenced by the traffic flow, the sound level of the moving vehicle, the radii of the equivalent moving line at the round road, the distance between the appraising point and the equivalent moving line at the round road, the distance between the appraising point and the equivalent inlet roads and the speeds of the vehicles.This paper choses some roundabouts to measure their traffic flow and traffic noise, the model is verified by comparing the measured noises with the simulated noises.More>

2003, 3(1): 80-83.

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Distribution characteristics and countermeasures of urban traffic accidents

CHEN Kuan-min, WANG Yu-ping

Abstract: The current situation of urban road safety in China was presented. Taking Xi′an as an example, the urban road traffic accidents characteristics, such as distribution of time, space and people etc were analyzed. The results indicate that driver is the main reason of traffic accidents that happen at the main road and the conjunction of urban and town, but foot passengers result in more serious accidents. The preventive countermeasures were given.More>

2003, 3(1): 84-87.

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Method of wear debris microscopical measurement based on stereo vision technology

YU Hui, ZUO Hong-fu, HUANG Chuan-qi

Abstract: The ferro-graphy has great value in the aero-engine operation inspection and the fault diagnosis technology. It is the most important step for the ferro-graphy to get the geometrical sizes of wear debris accurately. But up to now, there isn't a suit of efficient method to get the 3D size of wear debris, especially the thickness. Based on analysis and experiment on stereo vision applied in debris measurement, the whole system, including the hardware, software and arithmetic, was presented to solve the problem of debris measurement primarily. Based on the mechanism of stereo vision apperceiving the depth, optical microscope is applied to simulate the stereo mode to image, and add to the matching method and computing method to processing the image pairs. The system gets the thickness of debris, and the feature of wear debris surface is reconstructed based on the altitude distributing. The method has a better effect, and the results of data or model reach the prospective aim.More>

2003, 3(1): 88-92.

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Aero-engine maintenance cost

SUN You-chao, ZUO Hong-fu, NI Kai

Abstract: There exist universality of high cost and low benefit in Chinese civil aviation, their flying cost and maintenance cost are much higher than that in foreign aviation, a very important reason is lack of the sciencific and effective management and control for the maintenance cost.The analysis and evaluation for management of aero-engine maintenance cost were studied according to the situation of Chinese civil aviation.The new classification method of maintenance cost, basic influence parameters, general evaluation methods and program of maintenance cost were presented.Some schemes on aero-engine maintenance cost management method and measurement were put forword.The research will provide guide for reducing operating cost and improving the management level of maintenance cost.More>

2003, 3(1): 93-96.

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Simulation method of airspace capacity evaluation at terminal area

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

Abstract: The terminal area capacity is always the key problem in capacity evaluation. A definition of the terminal area capacity and its influencing factors were presented. According to the characteristics of the terminal area, the key techniques and the difficulties were pointed out. Taking Beijing Airport as an example, this method was examined, the result shows that the simulation method is feseable.More>

2003, 3(1): 97-100.

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Method and computer technique for control sector optimum partition

HAN Song-chen, ZHANG Ming, HUANG Wei-fang

Abstract: The sector partition is an important work of air traffic management, its operation affects the airspace capacity and security. The theoretic base for sector optimization, including the mathematical model describing the airspace structure of the topology, the statistic method of controller's workload, and the mathematical model for workload computation etc, is analyzed and established.The mathematical method for sector optimum partition is found, and the controller's workload-based application of sector optimization is programmed. The result of a practical example validated the correctness of theoretic base and the application for sector optimization.More>

2003, 3(1): 101-104.

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Economic analysis of railway freight transport integration

FENG Fen-ling, LI Xia-miao, TAN Zhong-ping

Abstract: The influence of railway freight transport integration on the demands and supplies of railway goods transportation was analyzed, it is pointed out that the demands of railway freight transport will remain steady in short period, and increase in long period after railway freight transport integrated, and the supplies of railway freight transport can be increased. By the principles of economics, the change of consumer surplus, producer surplus and social surplus with railway freight transport integration was discussed, it is indicated that railway freight transport integration can make the social welfare increase.The results show that railway freight transport integration is Pareto efficiency, Chinese railway freight transport integration should be developed continually.More>

2003, 3(1): 105-107.

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New methods for project finance in water transportation infrastructure construction in China

SHAO Rui-qing

Abstract: As an important component part of the national transportation, water transportation exerts a direct influence on the development of the national economy and China's entering the world economy.Water transportation infrastructure construction needs a great sum of money to invest.The lack of study on the application of some new methods of project finance results in the present situation of the unitary financing channel and the shortage of investment in water transportation infrastructure construction in China.Based on the technical economical characteristics of BOT, TOT and ABS, the possibilities and necessities to apply these project finance methods to water transportation infrastructure construction in China were studied.Some ideas about the measures to apply the project finance methods were put forward.More>

2003, 3(1): 108-113.

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Review on safety assessment for ships under heavy sea

LIU Da-gang, ZHENG Zhong-yi, WU Zhao-lin

Abstract: Safety assessment for ships under heavy sea is a very important topic to learn for both deck officers and marine authorities.Seeking for safety assessment methods that are easy to operate is one of the most important aims for researchers. This paper comprehensively introduced and summarized different kind methods of safety assessment for ships under heavy sea, a comparative analysis for both their merits and demerits was given, and the orientation and focal point for the future research was pointed out.More>

2003, 3(1): 114-118.

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Intelligent designing of aids to navigation system

ZHANG Yan, LI Hai-quan

Abstract: Due to the marine enterprise's constant development, safe navigation is especially important, which makes the renovation of the aids to navigation(AtN) become urgent. The popularity of computers, GPRS availability, the appearance of bluetooth provide conditions for the renovation of aids to navigation facilities and make them possible to be realized. To realizing telemeter and remote control of the AtN have an important mean for improving utilization ratio and management.More>

2003, 3(1): 119-122.

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Technology of blending LPG in diesel engines of urban buses

LI Ge-sheng, DONG Jian, ZHANG Xin-tang, PAN Zhi-xiang, GAO Xiao-hong

Abstract: Aiming at the working characteristics of bus diesel engines, the tech-strategy on blending LPG in diesel engines was presented.Using a type of bi-fuel supply system that was characterized by a mould pattern, the content ratios of diesel /LPG fuel were determined by engine experiments. The engine experiments and the bus engine tests indicate that the strategy is able to meet the demands of the urban buses.More>

2003, 3(1): 123-126.

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