交通运输工程学报

Static strength and mode analysis of B-type subway body

YANG Bin, SUN Qing-hong, HUANG Wen-jie, ZHU Zhuang-rui, DAI Jia-peng, JIANG Yan-qing

Abstract: A particular finite element analysis model of subway vehicle car body structure was set up with finite element method and ANSYS software, tow truck was taken as analytical object according to subway vehicle load and dangerous grade, the FEM calculational loads, constant operating conditions and assessing standards of the model were confirmed, subway bodywork static strength under all-setup and its inherent frequencies and vibration model were reckoned. The result indicates that the static strength of subway car body structure satisfies the relative design requirements in constant operating conditions, at the same time, its first step torsion and vertical bend vibration frequencies are smaller than 10 Hz, which is overall bogie pitching frequency. It is pointed that reducing its secondary vibration frequency can improve its primary vibration frequency and alleviate body mass by improving stiffness while decreasing structure mass.More>

2006, 6(2): 1-5.

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Numerical simulation and parameterized investigation of aerodynamic drag performances of high-speed maglev trains

SHU Xin-wei, GU Chuan-gang, LIANG Xi-feng, GAO Chuang

Abstract: The flow fields around streamlined high-speed maglev trains, including train TR08 and four new trains designed by changing the profile or length of longitudinal projection, were simulated with 3-D compressible viscous fluid theory. In order to evaluate the aerodynamic drag performances of different nose configurations, a non-dimensional parameter defined as total slenderness ratio, which indicated the configuration features, was brought forward as evaluating criterion, the influences of the horizontal and longitudinal projections of train streamlined noses on the drag performances were taken account. Simulation result shows that when other parameters are same, the aerodynamic drag decreases with the length increase of the streamlined nose, while the drag of middle car varies within a small range, when the length of streamlined nose is almost same, the aerodynamic drag of front car with protruding longitudinal profile is less than that of the concave, while that of the rear car is contrary. The order of total slenderness ratios of the five trains is as same as that of aerodynamic drag coefficients. Investigation result shows that increasing the length of streamlined nose is one of the effective ways to decrease train aerodynamic drag, and the total slenderness ratio can well reflect the streamlined configuration influence on train drag.More>

2006, 6(2): 6-10.

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Active control of pantograph vertical vibration of tilting train

LUO Ren, CENG Jing

Abstract: In order to study the active control of pantograph vertical vibration, the mechanical-electric coupled nonlinear dynamics model of tilting train was set up, the linear model and nonlinear model for pantograph were constructed respectively, the finite element model and static contact stiffness model of the catenary were developed, the models were coupled together to constitute the tilting train-pantograph-catenary dynamics system. The P controller and H_∞ robust controller were designed, the dynamic behavior of pantograph with P and H_∞ robust controllers was studied by numerical simulation method. Numerical simulation result shows that the contact force between pantograph and catenary fluctuates heavily during curving negotiation when without pantograph vertical control, the fluctuation of the contact force can be reduced evidently if active vertical control is used, H_∞ controller has better control performance than P controller when the time delay of the control system is taken into account, the catenary vibration!influences the contact force, but the controllers work well too.More>

2006, 6(2): 11-16.

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Probabilistic character for S-N relations of high carbon-chromium bearing steel in super-long cycle life region

LI Wei, LU Lian-tao

Abstract: In order to accurately evaluate the fatigue S-N (stress-life) test data of high carbon-chromium bearing steel in super-long cycle life region, the entire S-N data and the S-N data based on differentiating fatigue crack initiation mechanisms were fitted by general maximum likelihood method respectively, its probabilistic S-N curve models were established. Analysis result shows that the test data can be well fitted and the S-N curve can be well depicted with differentiating fatigue crack initiation mechanisms. It is discovered that when load level is above the fatigue limit (about 1200 MPa), the S-N curve that fatigue crack initiates from surface should be chosen, on the contrary, the S-N curve that fatigue crack initiates from subsurface should be chosen. It is proved that the material's probabilistic S-N curves, including survival probability-stress-life curves, confidence stress-life curves and survival probability-confidence-stress-life curves, can be determined, and the probabilistic characters for the S-N relations in super-long cycle life region can be depicted by general maximum likelihood method.More>

2006, 6(2): 17-21.

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Replacement thickness analysis of cutting in expansive soil area

TIAN Hai-bo, WANG Bing-long, XU Kai

Abstract: The inflexibility, intensity and deformation of expansive subgrade were taken into account, the reasonable replacement thickness of cutting in expansive soil area was deduced by expansive force balance theory and allowing rail deformation method, the expansive deformation of subgrade under different replacement thicknesses and expansive forces was researched by FEM, the inflexibility, intensity and deformation of subgrade were evaluated by in-situ test along Hefei-Nanjing railway in China. The result indicates that the muximum elastic deformation is 0.62 mm and the total plastic deformation is 0.65 mm when the subgrade is acted by 2 million times circular loads, the subgrade presents a good performance of stability and dynamics. It is feasible that the lime soil is taken as subgrade replacement material when its thickness is 60 cm, the expansive soil deformation is the main factor to determine the replacement thickness of cutting.More>

2006, 6(2): 22-25.

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Dynamic response of continuous girder bridge under moving vehicular loads

LIU Hua, YE Jian-shu, ZHANG Tao

Abstract: Bridge and vehicle were treated as two separate systems, vehicle was modelled as 2D nonlinear model, the effect of road surface roughness was considered, their dynamic equations were developed by virtual work theory and mode superposition theory, their uncoupled equations were solved separately by an iterative procedure while the geometrical compatibility condition and equilibrium condition of the interaction forces between bridge and vehicle were satisfied. The dynamic response of continuous girder bridge under moving vehicular loads was studied. The results show that the impact parameter when vehicle moving on side span is larger than the one when vehicle moving on middle span, the impact parameter is related to those factors, such as the dynamic properties and velocity of moving vehicle, the roughness of road profile and the dynamic properties of bridge, it is too simplified to take the impact parameter only as the function of the nature frequency of bridge.More>

2006, 6(2): 26-29.

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Nonlinear stability analysis of long-span curve bridge with high piers during cantilever construction

WANG Jun-li, HE Shuan-hai

Abstract: In order to improve the structure stability of curve rigid frame bridge with high pier and long-span during cantilever construction, bridge structure geometry nonlinearity and material nonlinearity were considered, the stabilities and max-displacements of the bridge were analyzed by finite element method with different central angles of curve, different slenderness ratios of pier and different tie-girder numbers in each situation, the relations of bridge critical stability coefficient and max-displacement with the central angle of curve, slenderness ratio of pier and tie-girder number were studied. The result shows that the nonlinear stability coefficient of bridge is 35% of eigenvalue flexure load, the central angle of curve dominates the critical stability coefficient and the max-displacement, it is not favorable for bridge stability that the number of tie-girder is more than two.More>

2006, 6(2): 30-34.

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Mathematics model of underwater turbine engine system

LUO Kai, DANG Jian-jun, WANG Yu-cai

Abstract: In order to guarantee the high performance and efficiency of open loop thermal cycle underwater turbine engine system, the operation behaviour of system working in the condition of variable depth and speed was analysed, the gas speed of nozzle was calculated, the output moment of turbine engine was studied, a dynamics mathematics model being fit for system optimization and new controller design was built, close algebra equations composed by system rotation rate, voyage body speed, combustor pressure, voyage body depth, propellant wastage and pressure rate were gotten by using the stabilization behaviour of the mathematics model. All the design parameters of power system can be optimized by taking pressure rate as key parameter and taking maximal variable speed combination voyage as optimizing target. Applied result of the model shows that the efficiency of power system is improved over 8 %/0. 3 figs, 6 refs.More>

2006, 6(2): 35-38.

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Optimum estimate method of intake flowrate for electronic control gasoline engine

TAN De-rong, LIU Zheng-lin, YAN Xin-ping

Abstract: The bench test of electronic control gasoline engine was carried out, the nonlinear character of engine intake system was taken into account, the relation between manifold pressure and intake system parameters was given based on engine intake dynamic model. According to the application trait of Kalman filter, an estimate method of engine intake flowrate was put forward based on extended Kalman filter (EKF), the iterative equation was obtained by the simple linearization of nonlinear system, the intake pressures of transient operation condition were computed with different load rates. The comparison result of computation value and measure value shows that their deviation is within 3% for low load ratio, and has increasing tendency for high load ratio, but it is within 5%. The result indicates that the method can compute engine transient intake quantity exactly.More>

2006, 6(2): 39-42.

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Performances of electronic fuel injection engine fueled with methanol-gasoline blended fuel

QI Dong-hui, LIU Sheng-hua, LI Hui, LU Sheng-chun

Abstract: In order to study the effects of methanol-gasoline blended fuels with different methanol volume fractions on the performances and exhaust emissions of multi-point EFI gasoline engine, the power performance, fuel economy and emission characteristic of the engine were analyzed through engine test, the non-regulated pollutant emissions, such as methanol and formaldehyde, were measured by using gas chromatography (GC), their emission characteristics and formation mechanisms were studied. The result shows that under the speed characteristic of full load, the power output of blended fuel engine is slightly higher at high engine speed, the brake specific fuel consumption is lower, and the effective thermal efficiency is higher compared with gasoline engine. Under the load characteristic of operation, the brake specific fuel consumption and effective thermal efficiency is almost similar to that of gasoline engine. With the increase of methanol volume fraction in the blended fuel, CO emission decreases, NO_x emission varies little, and THC emission slightly increases at high engine loads. Formaldehyde emission of blended fuel engine is evidently higher than that of gasoline engine, and increases with the increase of methanol volume fraction, but the methanol emission of blended fuel engine is lower.More>

2006, 6(2): 43-46.

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Asymmetric information theory and nonlinear backstepping robust control algorithm of ship navigation

ZHANG Xian-ku, GUO Chen, DU Jia-lu

Abstract: For a nonlinear course keeping system of ships, asymmetric information theory and robust control algorithm were applied to simplify nonlinear backstepping algorithm, through the algorithm, the controller was converted into nonlinear items plus a normal linear control item, and a simplified nonlinear robust control algorithm was presented, which connected the backstepping algorithm with closed-loop gain shaping algorithm. Simulation result shows that the ship can keep the set course without overshoot and steady state error, the regulating time is 600 s, these control indexes accord with the actual condition of ship navigation, and the course keeping performance is improved. When wind and wave disturbances are introduced into the system, the control effects are satisfied, the output course does not have steady state error, the controller has good robustness. The control effect does not vary obviously whether the nonlinear items are cancelled or not, the control performance is guaranteed.More>

2006, 6(2): 47-50.

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Fixation distribution of driver while driving through passageways with different widths

GUO Ying-shi, FU Rui, ZHANG Jian-feng, YUAN Wei

Abstract: In order to understand the perception-decision-operation pattern of driver, the eye movements and fixation distributions of driver, and relevant vehide speeds were measured by eye-measured instrument while driver drove between two barriers with five different space widths, which are 7.0, 4.4, 3.5, 3.0 and 2.0 m. Analysis result of driver fixation distributions concerning different widths shows that driver concentrates his vision on the central area of road and farther to vehicle when there were no barriers on road (referring to 7.0 m space width), he concentrates his vision on the central area of road and left barrier when the space is enough to pass (referring to 4.4 and 3.5 m space widths), he quickly scans between barriers when the width becomes narrow (referring to 3 m space width), he fixates closer to vehicle and his fixation duration decreases when the driving task becomes more difficult to fulfill.More>

2006, 6(2): 51-54.

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Method of moving pedestrian detection and tracking based on monocular vision technology

CHANG Hao-li, SHI Zhong-ke

Abstract: In order to effectively detect and track moving pedestrian in urban traffic scenes, a method of moving pedestrian detection and tracking by using the data from a fixed CCD camera was presented. Self-adaptive background subtraction method and dynamic multi-threshold method were adopted for background subtraction and image segmentation respectively. During the process of tracking, a new method based on gray model GM (1, 1) was proposed to predict pedestrian motion, a template of pedestrian continuous tracking was presented by fusing several characters of targets. Experimental results of two real urban traffic scenes show that 95% of single pedestrians can be detected and tracked, 87% of multi-pedestrians can be detected and tracked.More>

2006, 6(2): 55-59.

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Signal timing optimization of urban single-point intersections

WANG Qiu-ping, TAN Xue-long, ZHANG Sheng-rui

Abstract: In order to mitigate city traffic jam, the traffic flow characteristics and capabilities of urban intersections were analyzed, a nonlinear function model of urban single-point intersections was put forward, in which shortest average delay and stopping time were taken as objectives, and phase effective green time, saturation degree and cycle time length were taken as restrictions, the objective function of the model was solved by genetic algorithm and genetic simulated annealing algorithm. Solved result indicates that average delay is optimized from present 40. 394 s to 10^-3 s by genetic algorithm and genetic simulated annealing algorithm, the average stopping time is reduced and the good benefit value of the function is obtained, the intersection service level is improved from level C to level A. 7 tabs, 6 figs, 8 refs.More>

2006, 6(2): 60-64.

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GPS/DR navigation data fusion method based on Kalman filter

YU De-xin, YANG Zhao-sheng, LIU Xue-jie

Abstract: To realize the data fusion of integrated navigation system and improve the precision and reliability of GPS/DR, the characteristics of traditional methods tracking vehicle based on GPS and DR were analyzed, the advantages of GPS and DR were studied, an adaptive joint Kalman filter based on Kalman filtering technology was set up, its computer simulation system was designed by using Matlab software. The software realization problems of serial port communication in the integrated technology for GPS/DR were discussed, the navigation positioning errors of GPS, DR and integrated GPS/DR were computed. Computation result shows that the integrated GPS/DR navigation can actualize real-time, credible and exact vehicle positioning, its positioning error is minimum, it can decrease or eliminate the reckoning positioning system error accumulated with time.More>

2006, 6(2): 65-69.

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Intelligent traffic simulation based on agent and cellular automata

PAN Ming-yang, YAN Fei, XIE Hai-yan

Abstract: The agent and cellular automata are mostly applied into traffic simulation separately. Their characteristics, merits and limitations applied in traffic simulation were studied, the feasibility of traffic simulation with the combination of agent and cellular automata was discussed, a new idea of traffic simulation based on the combination was proposed. It is pointed out that the two approaches are both based on the idea of "Bottom-Up", agent can reflect the autonomous characters of various complex traffic elements, but its realization is complex and has lower efficiency, cellular automata is difficult to reflect the difference of different traffic elements, but its realization is really simpler and has higher efficiency. Simulation result shows that the new modeling method of traffic simulation not only can reflect the simple and high efficient merits of cellular automata, but also can reflect the autonomous characters of traffic elements and the difference of different traffic elements.More>

2006, 6(2): 70-74.

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Choice model of parking behaviors in urban

CHEN Jun, ZHOU Zhi-yong, WANG Wei

Abstract: In order to enhance the function of parking information query and guidance, offer drivers some proper direction with preferred and candidate parking dots before their trips, a multi-object parking behaviors model was set up to minimize trip time, walking distance and parking fee, the heuristic algorithm was used to solve the model. The model was tested with an example. The result shows that the model can select multi-plans with rationality under restristive conditions for driver's parking, these rational plans can give a decision evidence for driver selecting parking dots.More>

2006, 6(2): 75-79.

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Fuzzy synthetic evaluation model of transportation routes of dangerous goods

LIU Hao-xue, ZHOU Xun, YANG Jun-ru

Abstract: In order to optimize the routes of TDG (transportation of dangerous goods) by multi-level fuzzy synthetic evaluation method, the ecological environment, densely populated district and traffic situation were determined as major factors that influence the safety of TDG to ensure transportation safety and to reduce transportation accidents of dangerous goods, a fuzzy synthetic evaluation model was established. The safe degrees of roads G108, G210 and G316 were computed with the method. The result shows that G316 is relatively safe, which accords with the evaluation result of road experts. The model is effective for finding an optimum vehicle trip route to reduce the harm degree of TDG.More>

2006, 6(2): 80-82.

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Vehicle route algorithm of logistics distribution

NIU Yong-liang, WANG Jin-mei

Abstract: In order to reduce the complex network distribution system was presented network distribution systems. In view of th costs of logistics distribution, three steps oglstics after analyzing the properties of present logistics e second step VRP network model, customers were divided into different regions by quadtree principle, VRP was optimized by the saving and 2-opt methods of heuristics algorithms. The design of algorithms was realized by C program. The computation results of C program and LINGO program are same by simulative test, and the running time of the algorithms is less than the one by LINGO program, which proves that the algorithms are high-efficiency and feasible. 3 tabs, 9 figs, 8 refs.More>

2006, 6(2): 83-87.

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Probability distribution of vessel traffic flow in Xijiang waterway

YU Jing, ZHANG Wei, JIANG Ji-hong, LIAO Peng

Abstract: In order to improve inland waterway capacity, the arrival distribution and headway distribution of vessel traffic flow were analyzed. Based on the data of ship arrival in Xijiang waterway in 2004, the average values of daily-arriving-ship quantity and headway were assumed by mathematical statistics, the observed values of vessel traffic flow were compared with the ones of theory computation by time guarantee percentage method. The result shows that their relative errors are within 5%, the daily-arriving-ship quantity is close to Normal distribution, the headway is close to Erlang distribution in inland waterway.More>

2006, 6(2): 88-93.

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Safe-economic decision making model of ship's avoidance routing to tropical cyclone

LIU Da-gang, WANG De-qiang, WU Zhao-lin

Abstract: In order to take TC (tropical cyclone) forecasts from different observatories into consideration, make quantitative assessment and analysis for avoiding TC routes from the views of safety and economic benefit, a new safe-economic decision making method of TC avoidance routing on ocean was put forward. The model is based on the combining forecast of TC route neural networks, the technical method to determine future TC wind and wave fields, the technical method of fuzzy information optimization, risk analysis theory and meteorological-economic decision making theory. It was applied to the simulation of MV Tianlihai's shipping on ocean. The result shows that the model can select the best plan from 7 plans, the selected plan is in accordance with the one selected by experienced captains.More>

2006, 6(2): 94-98.

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Highway tolling reform and its influence on truck development

CHEN Yin-san

Abstract: In China, there are a lot of tolling highways and the expense of truck transportation amounts to a great percentage of transportation cost. However, the present tolling system has nothing to do with the total weight of truck, which results in the emergence of huge amounts of over-loaded truck transportation. So, it is necessary to collect tolling fee according to the total weight of truck, with less fee from lighter truck or vacant truck, more fee from heaver truck and even more fee from over-loaded truck so as to make up the necessary expense for the over-use of highways. This reform can greatly stop over-loaded truck transportation and improve the truck structure in China so as to make it catch up with that in the world. But in China, tailer truck is not allowed to run on expressways according to Chinese highway transportation safety law, the number of truck axes can not be more than 6, which is quite different from that (as many as 9 axes) of advanced countries.More>

2006, 6(2): 99-106.

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Government regulation of road passenger transportation

WU Qun-qi, LI Li

Abstract: In order to establish effective safety guarantee system in road passenger transportation, ensure passenger life and property, the role in carrying trade, market characteristics, resource assign element, development power and technical hazard of road passenger transportation were analyzed. It was pointed out that passenger transportation was not belong to usual market competition field, so government should take rigid regulation on the trade. A series of measures, such as how to control the entrant, how to supervise the safety guarantee system of enterprise and how to make its action reach criterion, were presented, and the measures should be carried out as quickly as possible in China.15 refs.More>

2006, 6(2): 107-112.

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Panel data analysis of highway financing structure change in USA

LI Qing-rui, DU Jun, LU Yi

Abstract: In order to determine the factors that affect highway financing, a fixed effect model and a random effect model were built, the parallel data of 50 states in USA were examined by panel data regression method, the relationships between expressway financing structure and economic structure & population structure were analyzed. The result indicates that the influence of PGNP and population density on local government financing structure is more obvious than on state government, the subscribed capital proportions of 65% population and the male have significant time series effect on state government financing structure, the subscribed capital proportions of female users and highway non-users are gradually balanced. The study has practical significance and reference value to expressway financing during economic conversion period in China.More>

2006, 6(2): 113-117.

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Market access and withdrawal mechanism of taxi operation based on service quality bidding

YANG Ren-fa, YANG Ming

Abstract: The shortcomings of current market access operation on administrative permitting and the policies of auctioning and bidding in Chinese taxi industry were analyzed. It was pointed out that the mechanism should be developed to encourage service quality competition, perfect economic structure, speed operation style reform and keep field order. In order to implement the principles of service quality bidding system, some suggestions were proposed to solve the key problems of policies and statutes corrdination, service quality evaluation, taxi rewarding use reform and old new policies coherence. Applied result indicates that the mechanism not only can deal with the economic conflicts among local government, taxi companies and taxi drivers, but also can guide the reform of taxi industry.More>

2006, 6(2): 118-124.

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Keyword choice principles of science-technology paper

ZHAO Zhi-hong

Abstract: Based on analyzing the unbending, disorder, nonstandard properties of keyword choicefor science-technology paper, the paper put forwardlogistic, accurate, canonical choice principlesof keywords, gave a topic division method of keywords. Applied result indicates that the methodcani mprove keyword distilling efficiency, the principles cani mprove the exact and complete ratesof keyword search.More>

2006, 6(2): 125-126.

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