交通运输工程学报

Feng Quan-bao, Liu Jian-xin, Lu Shi-yong

Abstract: In order to improve the fatigue life and surface pressure stress of 50^# steel axle, its stress change rules were analysed, its residual stress was measured by X ray method when the axle surface was going through the process of low-temperature quenching and the various process of rolling and pressing.Measured results show that the residual stress of 50^# steel axle surface are improved greatly, the maximum improved value is 556 MPa, which shows that the method can efficiently improved the axle fatigue life cycle.More>

2005, 5(3): 1-4.

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Chatter mechanism of railway vehicle bogie under braking condition

Dai Huan-yun

Abstract: The chatter phenomenon of some locomotives and vehicles with lightning carbodies and bogies was analysed, which is very harmful to the carbodies, the ride comfort of passengers and environment.In order to decrease the level of the chatter in the condition of braking, the chatter mechanism was studied, the inflnence factors of the chatter were analysed, the dynamics relation of chatter and braking was put forward.The numerical simulation results show that the chatter is generated by the self-excited vibration of vehicle system at low speed, the chatter is related with the structure of vehicle bogie, carbody and suspension system, the chatter can be avoided by adjusting the parameters of bogie system and changing bogie frame design.More>

2005, 5(3): 5-7.

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Optimum-preview control model of rail vehicle active suspension

Zhu Hao, Liu Shao-jun, Qiu Xian-yan

Abstract: Based on the design model of multi-degrees of freedom, a new modelling method of rail vehicle system with active suspension was put forward, a kind of optimum-preview controller was designed to restrain the vertical vibration, nodding and rolling of carbody, the system respond with controller was analysed.Simulation results indicate that the vertical vibration, nodding and rolling levels of carbody are reduced by about 27%, 30%, 30% respectively using optimum control method, and the levels of carbody are reduced by about 54%, 50%, 45% respectively using preview control method, preview control strategy can make vehicle system respond ahead according to target value.It is feasible that the optimum-preview controller is used in designning the active suspension of rail vehicle system based on complex multi-degrees of freedom model.More>

2005, 5(3): 8-13.

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Prediction model of wheel-rail noise for rail transit

Xu Zhi-sheng, Zhai Wan-ming

Abstract: In order to accurately predict the wheel-rail noise of rail transit, the procreant mechanism of wheel-rail noise and the theories of vehicle-track coupling dynamics, noise radiation and propagation were analysed, a prediction model of wheel-rail noise was put forward.In the model, the wheel was considered as a LOVE's ring, the rail was considered as a Timoshenko beam, Hertz's nonlinear theory was employed for wheel-rail contact.Comparison analysis shows that wheel-rail noise main frequency ranges of TWINS software simulation values and the model computation values are consistent though there are some differences of noise peak frequencies for wheel-rail components, the noise measure values of the high-speed running experiment carried out on the Qinhuangdao-Shenyang passenger transport line agree well with the model computation values, their change trends are accordant.It indicates that the new model is reliable and reasonable, and meets the need of predicting and assessing wheel-rail noise.More>

2005, 5(3): 14-18.

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Mechanics computation model comparison of continuously welded rails on high-speed railway bridges

Xu Qing-yuan, Chen Xiu-fang, Zhou Xiao-lin, Yang Xiao-li

Abstract: The girder, abutment and pier as well as the loads of high-speed railway bridges are of strong spatial mechanics characteristics, the plane mechanics calculation model cannot reflect these conditions effectively, and has its limitations.Based on the achievements of the predecessors, a three-dimensional finite element spatial mechanics model for calculating the additional longitudinal forces of continuously welded rails on high-speed railway bridges was established.Taking a 10-span 32 m simple supported double-track box girder on Qin-Shen passenger special line as an example, the additional longitudinal forces were analyzed, and the calculation results of the new three-dimensional spatial model and traditional plane model were compared.The calculation results show that the flexiable additional longitudinal forces calculated by tow models are almost equal; for the winding force, there is distinct discrepancy between the two calculation results; when the double-track loaded with the symmetry braking force, the braking additional longitudinal forces calculated by the two models are almost equal; when one track braking or two track braking in opposite directions, the calculation result of the plane model is bigger than that of the spatial model, the braking additional longitudinal force calculated by the plane model is conservative, which indicate that the spatial model is more feasible and effective to calculate the additional forces than the plane model.More>

2005, 5(3): 19-24.

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Thermal stress influence factors of asphalt overlay on cement concrete pavement cracking slab

Chen Shuan-fa, Zheng Mu-lian, Yang Bin, Wang Bing-gang

Abstract: In order to remove the reflective crack of asphalt overlay on cement concrete pavement, the paper adopted finite element method, took pavement structure as elastic layered system, founded a three-dimensional model of asphalt overlay, strengthening layer, cracked slab of cement concrete pavement and subgrade, and analyzed the influences of old cement concrete cracked size, temperature drop scope, modulus and thickness of asphalt overlay, structure strengthening layer modulus and thickness of cement concrete cracked slab on asphalt overlay thermal stress.The results indicate that the thermal stress of asphalt overlay decreases greatly with the size reduction of old cement concrete cracked slab, the influence of great temperature drop scope on overlay thermal stress is much larger than that of vehicle load, the measures such as decreasing asphalt overlay modulus and increasing asphalt overlay thickness etc can effectively improve the stress situation at cracked slab joints, and effectively prevent the reflective crack of asphalt overlay.More>

2005, 5(3): 25-30.

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Fatigue properties of asphalt mixture with fiberglass polyester mat

Ni Fu-jian, Yin Ying-mei

Abstract: The fatigue properties of neat asphalt mixture(BN), asphalt mixture with 1^# fiberglass polyester mat(BT) and asphalt mixture with 2^# fiberglass polyester mat(BU) were analysed by universal testing machine(UTM), the fatigue life equation expressed strain and the equation between cumulative dissipated energy and cycles were established, the testing result was studied by energy method.It is found that the properties of BT and BU are better than BN, the cumulative dissipated energy has good relation with fatigue life.Energy method is feasible for evaluating and predicting the fatigue properties of asphalt mixtures, fiberglass polyester mat can greatly improve the fatigue performances of asphalt mixtures.More>

2005, 5(3): 31-35.

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Influence factors on post-construction settlement of high backfills adjacent to abutment

Liu Meng-cheng, Huang Xiao-ming, Tao Xiang-hua

Abstract: In order to analyse the post-construction settlement rules of high backfills adjacent to(abutment, ) a plane-strain numerical model was presented by ABAQUS/standard finite element code, the influence degrees of backfills parameters on settlement were studied.The simplified method is verified to be reasonable and feasible by making the comparison between the numerical analysis and field measure results because its computation result can indicate the rules and properties of backfills real settlement, some parameters, such as elastic modulus, permeability coefficient, unit weight and preloading time, are the major influence factors on the post-construction settlement of backfills.Perhaps the "bridge bump" is reduced while the mechanical characteristics of backfills and construction method are improved in design.More>

2005, 5(3): 36-40.

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Numerical simulation of cooling effect for heat pipe subgrade

Wang Shuang-jie, Chen Jian-bing, Huang Xiao-ming

Abstract: Based on heat pipe test engineering for the frozen soil subgrade distresses treatment of Qinghai-Tibet highway, the equivalent model of heat transmission for heat pipe subgrade was established and simulated using finite element method, the working cycle, operating condition and operating radius of heat pipe were discussed under Qinghai-Tibet highway environmental conditions, the cooling effect of heat!pipe in permafrost subgrade was compared with the two-year observation data of the subgrade.Comparison results show that heat pipe work is not continuous but fluctuant in one work cycle about five months, its actual working time is two-thirds of one work cycle, the cooling effect of heat pipe subgrade in winter is obvious, which is good for the contained cool increase of soil body and improves subgrade heat stabilization, there is a decrease for its cooling strength with the increase of horizontal distance, its effective operating radius is 2.25 m, its maximum cooling strength is in evaporation segment in depth direction, which low the thaw sensitivity of permafrost in the seasonal thaw layer about permafrost table.The results indicate that the space between heat pipes for 4.0 m is reasonable, the installation positions of heat pipes at two sides are better than at one side, pile oblique placement is better than perpendicular placement.More>

2005, 5(3): 41-46.

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Effective prestress computation of existing PC simply-supported beam

Liu Ling-jia, He Shuan-hai, Zhao Xiao-xing

Abstract: In order to evaluate the permanent prestress and structure loading capability of existing prestressed concrete bridge, the longitudinal pretensioning force was enforced on the simply-supported concrete beam to gain its natural frequency and deflection by post-tensioning structure method.Based on the relation of its fundamental frequency increasing with its pretension force's increasing, a regression analysis of the data was conducted to develop an equation of its effective stiffness, the computation value and the measure value of its deflection were compared.The analysis results show that the deflection errors of T and rectangular beams are within 10%, the errors of hollow slab beam are within 15.71%, which indicates that using the tested fundamental frequency and deflection can calculate simply-supported beam's effective prestress.More>

2005, 5(3): 47-51.

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Intelligent active control of railway girder bridge deflection

WANG Jing-quan, LIU Zhao, Lu Zhi-tao

Abstract: The active control of railway bridge deflection was investigated to reach the goal of micro-deflection. The concept of intelligent prestressed system (IPS) was presented. The configuration and details of IPS were introduced. The Chinese railway post-prestressed concrete standard girder bridge was analysed with finite element analysis method. An effectual and simple control algorithm for IPS was put forward. The results indicate that the ratio of girder span to mid-span deflection can reach 3 200, the highth of girder can be reduced by 10%, it is feasible that the system can regulate the force of cable in real time, and control the deflection of railway girder bridge.More>

2005, 5(3): 52-55.

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Static parameter identification of bridge structure based on Levenberg-Marquardt algorithm

Tan Dong-lian, Xiao Ru-cheng

Abstract: In order to improve the precision and stability of structural parameter identification in the procedure of bridge assessment, a heuristic method of using Levenberg-Marquardt algorithm to meliorate the singular iterative matrix of Gauss-Newton was put forward to overcome the harsh terms of initial value in Gauss-Newton algorithm, the numerical simulative test of a continuous beam with three spans was carried out.Simulation results show that the relative-effective error of bridge structure parameter identification is less than 10%, the application of Levenberg-Marquardt algorithm is feasible, its quantitative message can be put forward for bridge structure condition assessment.More>

2005, 5(3): 56-59.

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Effect of collapsible loess on pile foundation bearing capacity

Feng Zhong-ju, Feng Rui-ling, Zhao Zhan-chang, Xie Yong-li

Abstract: Based on elastic theory, a mechanics model of pile foundation bearing capacity was established, its calculating formula in collapsible loess was deduced, its changing characteristics for different collapsibility coefficients and different collapsibility thicknesses were analyzed.The comparison of calculation result and measuring result show that its minimum relative error is 5.2%, its maximum relative error is 6.7%, which indicate the model is feasible, the formula is practical.More>

2005, 5(3): 60-63.

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Intelligent control strategy of ship stowage based on expert system

Du Jia-li, Yang Yan-sheng, Zheng Yun-feng

Abstract: Based on analysing the multiple hierarchy control strategy with the combination of reverse inference and inference, the control rules of the loading position, loading turn and loading capacity, restrictive condition and realization principle of ship stowage and discharge were presented.Through the control of ship buoyancy and strength, the ballast water rate and discharging ability of ship could be increased to ensure the equivalence level of ship ballast water and cargo operation during ship loading, the strength of ship could satisfy the requirement of cargo operation, ship stowage plan, loading and discharging turns could be ensured.Calculation results of real ship show that the method provides the property indices in every step during cargo operation, such as the loading order, time and buoyancy of ship, etc, confirms ship stowage plan and operation procedure quickly and reasonably, improves the efficiency and avoids the blindness during ship stowage.More>

2005, 5(3): 64-68.

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Dynamic simulation model of automobile compressed air brake system based on bond graph theory

Chen Yan

Abstract: Based on analysing bond graph theory and the braking properties of automobile compressed air brake system, the bond graph models of two-barrel brake valve, brake diaphragm chamber, emergence relay valve and gas flow in pipe were set up.The comparison analysis of the models and traditional models of automobile brake system shows that their variables are fewer, they are known easily, some components are added and decreased to the models easily, which are useful to the dynamic simulation and control of the brake system.More>

2005, 5(3): 69-72.

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Calculational methods of avoiding flight conflict in low altitude airspace

Zhu Dai-wu

Abstract: According to the flight separation regulations of air traffic management rules and the analysis method of airspeed vector triangle, the basic condition to avoid conflict between aircrafts in low altitude airspace was studied, the airspeed vector relationship of aircraft A and B was revealed, the calculation model of changing velocity and heading angle was obtained, and two kinds of methods to avoid flight conflict were put forward.The calculation model was approved by experiments on DRS-98 radar simulator.It is concluded that the conflict can be avoided by changing heading angle in any time, the more the distance and heading difference between the aircrafts are, the less the heading angle change is.When the distance between aircrafts is more than 6 times fligh separation, changing velocity method should be used, and the aircrafts can keep their scheduled flight courses.More>

2005, 5(3): 73-76.

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Ship navigation system based on distributed WebChart

Pan Ming-yang, Zhao De-peng, Wang De-qiang, Li Shao-xi

Abstract: In order to improve the information transmission efficiency, realize the information interaction for WebChart ship navigation system, its main technological issues were analyzed, such as the network transmission of chart data, the access of local navigation devices, the information interaction among clients, and so on, and a kind of distributed WebChart ship navigation system was constructed.Digital signature and JNI(Java native interface) technologies were used to solute the issue of access local resources and attain ship information from sensors connected with client machine through serial-port.The distributed architecture of the system not only enables ship users to obtain chart services through web browser, but also enables them to see each other and interact information on the chart platform.So, in the system, comprehensive navigation services can be provided through web browser for ship users in order to help them to analyse and comprehend the static and real-time dynamic sailing environments exactly.More>

2005, 5(3): 77-82.

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Risk degree assessment model of navigating ship on heavy sea

Liu Da-gang, Xu Dong-hua, Wu Zhao-lin

Abstract: Based on the theories of risk assessment and fuzzy comprehensive assessment, a new model of quantitative assessment to compute the risk degree of navigating ship on heavy sea was put forward.Using expert questionnaire method, the fuzzy relation matrix of occurring accident in different levels for a certain Ro/Ro vessel navigating on heavy sea was obtained, the risk degrees of different routes were calculated.The results show that on heavy sea the vessel faces a bigger risk degree on normal route, it has least risk degree on customary go-north route, it has a relative bigger risk degree on the compromise route of the two routes.It can be seen that the model can describe the risk degree of ship navigating on heavy sea quantitatively and objectively, it is useful for ship risky decision-making.More>

2005, 5(3): 83-86.

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Measures for breaking down monopoly of Chinese railway

Li Dai-an, Chen Zhong

Abstract: Under the long influence of planned economy system, Chinese railway system has the characteristics with the combination of government and enterprise, uniformed operation management, the monopoly of nature and administration, they are harmful to the social common benefits.Its market role, economic characteristics, dignities of natural monopoly and administration monopoly were analyzed.The necessity and possibility to break down the railway situation of unique monopoly in order to adapt to the demands of marketing system and deep economy system reforming were studied.It is pointed out that breaking down the monopoly needs to wipe out the combination system of government and enterprise, form the competition system depending on fast rail development, fasten the reform of railway investment system and ownership construction, creat the firms according to market company system, and loosen the governmental control on the tariffs.More>

2005, 5(3): 87-92.

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MD forecasting model of passenger traffic volume for newly-built high-speed railway in transport corridor

Peng Hui, Wang Jie

Abstract: In order to accurately analyze the future passenger traffic volume of newly-built high-speed railway in transport corridor, using the utility principle of economics and the analytical method of mathematics, the paper studied the conception, hypothesis and principium of MD model, discussed the mechanisms of the potential demand and requirement achieve ratio, the total payment of travel and the choice of varies transport.The forecasting results of MD model and conventional method indicate that the market percentage of newly-built high-speed railway is approximately 70%, the annually increasing ratio of potential demand volume reduces by 1%, which adapt to the change of traffic volume, the way of combining MD model with conventional method of traffic volume forecasting can reflect the relations between different service levels of transport and their market percentages well.More>

2005, 5(3): 93-97.

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Design method of indented bus priority approach

Wang Yuan-qing, Zeng Yi-lin

Abstract: In order to reduce the delay of buses, the indented bus priority approach was designed, its work process, platoon arrival flow, passing capacity and the used condition of advanced bus's parking area were studied.An optimized model that adapted to the needs of its platoon arrival flow and passing capacity was put forward, the fitting condition for building the indented approach was determined, its main signal and advanced signal were calculated, the suitable length of its waitting area was computed.Through an example, the delays of buses and other vehicles in the conditions of having indented approach and no-having indented approach were calculated.The results show that the average delay of buses is reduced by 3.7 s, the average delay of other vehicles is increased by 1.4 s, the delay of all passengers is reduced by 2.4 s, in the condition of having indented approach.More>

2005, 5(3): 98-104.

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Resident travel time choice and congestion pricing policy

Li Zhi-yao, Juan Zhi-cai, Zong Fang

Abstract: The distribution rules of resident travel time and the influence factors of resident travel time choice were analysed by activity-based travel demand forecasting method, two time choice models that could forecast the time of the start and end points of a trip were developed respectively, the models were estimated and validated with the survey data in Changchun city.It is proved that two strategies of increasing car costs in peak periods not only can reduce resident travel by 18% in peak time periods, but also restrain resident travel by car and adjust traffic mode structure in urban area.The results indicate that established activity-based time choice models can completely and effectively evaluate transportation management policy.More>

2005, 5(3): 105-110.

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Evaluation and prediction new methods of road traffic noise

Han Shan-ling, Zhu Ping, Lin Zhong-qin

Abstract: Based on the old evaluating methods of road traffic noise, the traffic noise integrated impact index was proposed, the unsteady characteristic of road traffic noise was considered.Using probability and traffic flow theory, a theoretical model of road traffic noise prediction was developed, the effect factors of traffic flow, vehicle types and traffic velocities were taked into account.According to the road traffic noise change of sound level A in a city with in 24 h, the calculation value of traffic noise integrated impact index is 79.7 dB.The result indicates that it is feasible to use the traffic noise integrated impact index to evaluate the harm of road traffic noise to people's health and social economy.More>

2005, 5(3): 111-114.

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Transportation subsystem design of third-party logistics information system

Yan Bo, Sun Hong-bo, Huang Bi-qing, Xiao Tian-yuan, Su Xiao-rong

Abstract: In order to reduce the complexity of the transportation subsystem design of third-party logistics information system in the system structure design, the transportation subsystem was divided into five parts, such as business system, monitor, query and statistic, finance interface and transportation fee adjustment; in the business flow design, Petri net was adopted to describe most business logics in order to optimize the transportation subsystem; in the database design, entities were identified from documents, data flow diagrams were drawn up based on interfaces, the relationships among entities(E-R) were identified from E-R diagrams, E-R were converted into relationship models and became the basic structures of tables in the database, and the method to organize entity sets and database tables in terms of the concept "family" was proposed, 125 pieces of tables established according to physical data model were divided into 14 families.These design methods can simplify the transportation subsystem structure design and improve project quality.More>

2005, 5(3): 115-121.

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Profit distribution tactics of intermodal transportation

He Zhu-qing, Sun Lin-yan, Gong Jun-tao

Abstract: In order to form a steady and harmonious intermodal transportation alliance, a profit distribution model based on game theory was set up, several profit distribution tactics were brought forward to suit different dependence degrees between leading member and alliance members.To general ally, the coefficient of profit distribution was obtained based on market price, but to strategic ally, the coefficient of profit distribution was proportion to the contribution and risk undertaken degree of ally.The applied results of the distribution tactics show that the transportation profit of leading member is increased by 1.184 6 million yuan in four years, the veracity of freight transportation is increased by 15%.More>

2005, 5(3): 122-126.

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