交通运输工程学报

Effect of rail irregularity wavelength on lateral runningcomfort of speed-raised train

Wang Kai-yun, Zhai Wan-ming, Liu Jian-xin, Feng Quan-bao, Cai Cheng-biao

Abstract: In order to improve the riding comfort of speed-raised train, the effect of rail irregularity wavelength on the running comfort of speed-raised train was analyzed by means of experimental data and based on vehicle-track coupling dynamics, the irregularities with different wavelengthes were calculated from rail power spectral density. Analysis result shows that if the wavelength range is from 1 to 20 m, the main frequency of carbody vibration is in the scope from 2.20 to 4.00 Hz and the riding index of speed-raised train is excellent at a speed of 150 km·h-1; if the wavelength scope is from 20 to 30 m, the main frequency will decrease to the level of 1.50 Hz, which is accordable to the sensitive frequency of body, the riding comfort will reduce greatly, and the riding index will increase by more than 20%; the long wavelength is more than 30 m, the riding comfort changes little, and the riding index is the same as that of medium wave range from 1 to 20 m. Obviously, in order to improve riding comfort of speed-raised train, much measure should be taken to control the wavelength scope from 20 to 30 m on existing lines.More>

2007, 7(1): 1-5.

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Integrative method of design and manufacture on streamlined head of train

Xu Ping, Tian Hong-qi, Yao Shu-guang

Abstract: In order to insure that the streamlined shape of train head is consistent with its structure, the characters of the shape and structure were analyzed, and a design and manufacture integrative method of the shape and structure was developed on the ARX of AutoCAD and the Open I-deas of I-deas software flat roof. The method includes three modules. The first is shape design module based on non uniform rational B spline(NURBS) theory, the second is structure design module based on the intersection theory between two NURBS surfaces and 3-D geometric modeling technique, the third is NC machining module of bend sheet-beams of head structure based on line approximation form of NURBS and programming technique. Applied result shows that the complex streamlined shape of train head can be promptly and freely designed according to human's will, the head grid structure made up of bend sheet-beams can be created automatically, and the relevant NC machining files of bend sheet-beams are made aimed at the different NC machining tools; the time-cost works, formerly cooperated among the departments of design, technique and machine, are fully finished by computer, an important revolution is realized in the design and manufacture of train head.More>

2007, 7(1): 6-11.

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Simulation model of maglev coupling dynamics performance based on SIMPACK

Deng Yong-quan, Luo Shi-hui, Liang Hong-qin, Ma Wei-hua

Abstract: In order to effectively evaluate the dynamics performance of maglev, SIMPACK was introduced, a vehicle-track-control system coupling dynamics model was established according to the topological relationship chart of maglev kinematics, and a test example was presented to detailedly verify the model. In the model, vehicle was treated as a full dynamic rigid multi-body model with doubled suspension systems, Euler beam was utilized to model rails, and the control system of maglev was also taken into consideration. Comparison result shows that the maximum deformation of beam is 1.5 mm, while the test result is 1.6 mm; the vertical accelerations of carbody in simulation and test are reasonable. So the model is feasible to test and evaluate the dynamics characteristic of maglev in engineering application.More>

2007, 7(1): 12-15.

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Reconstruction method of fatigue reliability S-N curves for railway wheel cast steel of grade B

Chen Lei, Zhang Zi-mao

Abstract: In order to realize the reliability strength design, fatigue life prediction and reliability assessment at an arbitrary probabilistic level for railway wheel cast steel of grade B, a reconstruction method of fatigue reliability S-N curves was proposed, the fatigue limits and the S-N data were reconstructed by a technique of Monte-Carlo simulation with acceptable error range, the basic reliability curves in the middle and short life ranges were estimated by conventional method, the reliability S-N curves in the middle, short and long life ranges were established by probabilistic fatigue limit extrapolating method. Taking the practical situation of engineering application into account, the mileage reliability curves at arbitrary probabilistic level were deduced. The maximum simulation errors for the reconstructed data of fatigue limits and the S-N data are only 0.15% and 0.07% respectively, the extrapolated curves can cover the range of more than 10⁴ km, it meets production demand, which shows that the reconstructed method is feasible.More>

2007, 7(1): 16-20.

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Sustainable development model of shipping and water environment in Yangtze River valley

Shi Xin, Huang Fang

Abstract: In order to accelerate the sustainable development of shipping and water environment in Yangtze River valley, a dynamic sustainable development model was constructed by using system analysis method and system dynamics model, the effects of different types of controlling policies and managing methods were simulated. Simulation result shows that the simulation values of sustainable development indices are close to their real values, the maximum error is 12.9%, the model can effectively simulate the sustainable development of shipping and water environment in Yangtze River valley; almost 90% of shipping pollution is usually caused by ship accidents and crew living garbages; the comprehensive development of population, water environment, shipping, industry and agriculture is helpful to improving water environment; it is the key to pay more attention to improve the management level of ship accident emergency decision.More>

2007, 7(1): 21-25.

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Arrangement algorithm outside ship lock during ship scheduling

Xiao Heng-hui, Qi Huan, Wang Xiao-ping, Liu Yun-feng, Chen Ying-chun, Ceng Liang

Abstract: In order to improve the navigation capacity of ship lock and optimize ship scheduling, the average opening intervals of ship locks of Three Gorges Dam were analyzed, and a new concept of arrangement outside ship lock was introduced. Based on the analysis of the operation process of ships' entering ship lock, a mathematic model with the objectives of safety and time was established, a corresponding heuristic solution algorithm was proposed, the arrangement approach of ships outside ship lock was educed through the objectives and constraints of the model. Numerical experiment analysis shows that the model is feasible, based on considering the time of ships' entering ship lock and the principle of safety, the arrangement algorithm can obtain the safe and efficient scheme of ship scheduling, shorten the opening interval of ship lock, increase the operation time of ship lock, and significantly improve the whole passing ability of ship lock.More>

2007, 7(1): 26-29.

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Numerical prediction method of 3-D tidal current

Huang Lei, Zhang Yong-ning

Abstract: In order to make mariner instantly acquire tidal current information in marine activities, a 3-D tidal current numerical prediction software of Yellow Sea and Bohai Sea was developed, based on the 3-D model established by Backhaus, the harmonic constants of tidal current at 7 000 points in different sea levels were calculated. Using the software, mariner can instantly obtain the charts of numerically predicted tidal current fields and tidal current information at any time and any point in Yellow Sea and Bohai Sea. Both curves of numerically predicted surface tidal current and measured surface current agree well, prediction accuracy is high, and the software can provide beneficial service for marine activities.More>

2007, 7(1): 30-33.

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Derivation on droplet size and velocity distribution functions in atomization

Cao Jian-ming

Abstract: For enhancing the mass and heat transfer of droplet in spray, and predicting and evaluating spray quality, new probability distribution functions of number, differential number, volume, differential volume and total volume formula on joined droplet size and velocity were derived by using maximum entropy principle and momentum conservation law. If droplet velocity distribution is not considered, the derived formula of droplet size distribution in spray has an absolute same form as the formula in Cao Jian-ming previous study, the droplet size distribution function is a special form of Nukiyama-Tanasawa size distribution function, the derivation results have universal availability.More>

2007, 7(1): 34-36.

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Control method of electric power steering system based on phase compensation

Miao Li-dong, He Ren

Abstract: The physical and mathematic model of electric power steering system with three lumped masses was studied by dynamics analysis and control theory, and the general block-diagram of the system was established; the outer loop property of the system was analyzed, then the general block-diagram was transformed into its equivalent counterpart, and steering control system was designed according to the system requirement; the transfer function of controlled plant, the block-eiagraph, Bode plot and Nyquist plot of the open loop system and the stability of the system were studied, and the testbed test of the system was carried out. It is pointed that the block-diagraph may be expressed by a two-loop diagraph with an inner loop including a feedback channel of back electromotive force and an outer one, back electromotive force may be ignored when a fast proportional-integral(PI) controller in inner loop was used, the gain and phase margin of the system are negative without phase compensation, the system is unstable, while phase compensation may stabilize the system. Analysis result indicates that a lead corrector with phase compensation around low frequency resonance is an effective method to stabilize the system and restrain the system vibration.More>

2007, 7(1): 37-42.

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Carrying capacity analysis of asphalt concrete and continuously reinforced concrete composite pavement

Ni Fu-jian, Lu Yang, Gu Xing-yu, Dong Qiao

Abstract: In order to prevent the early destruction of highway, provide theoretic analysis and technology support for the study of long life pavement structure, the thermal field and fatigue stress of asphalt concrete and continuously reinforced concrete(AC+CRC) composite pavement were analyzed by finite element method. Analysis result shows that the asphalt concrete layer with less than 4 cm thickness is mainly used to improve pavement performance, while the asphalt concrete layer with more than 4 cm thickness can improve pavement thermal field effectively, every adding 2 cm asphalt concrete can meet 15%~20% overload. It is indicated that the composite pavement can withstand heavy load and overload to a certain extent to avoid pavement fatigue destruction.More>

2007, 7(1): 43-48.

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Gussasphalt performances on bridge deck

Yang Jun, Pan You-qiang, Deng Xue-jun

Abstract: To discuss the applicability of domestic hard bitumen in bridge deck gussasphalt paving, the types of overseas common hard bitumen were analyzed, domestic hard bitumen, PmB45 made in laboratory and PmB25 made in Germany were selected, by means of indentation test, wheel track test, bending beam test and fatigue test, the performances of the gussasphalts made with the hard bitumens were evaluated. The result shows that the performances of the gussasphalt made with domestic hard bitumen meet the criterion of gussasphalt binder, the bending and fatigue performances of the gussasphalt made with modified hard bitumen excel that of the gussasphalt made with direct hard bitumen, but the rut resistances of the three kinds of gussasphalts are limited, and it is proposed that the made gussasphalts may be used in northern China.More>

2007, 7(1): 49-53.

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Differential settlement characteristics and influencing factors of widening subgrade

Fu Zhen, Wang Xuan-cang, Chen Xing-guang, Li Hong-zhi, Shi Jian-ping, Wang Lei

Abstract: In order to know the influence of differential settlement on widening subgrade, the differential settlement characteristics of widening subgrade were analyzed by finite element method, and the influences of subgrade height, compressive modulus, widening mode and width on the differential settlement and settlement curves of subgrade were studied. The result shows that differential settlement controlling on widening road with two sides is better than that with one side, the maximum differential settlement decreases from 20.58 cm to 5.46 cm when compressive modulus increases from 2 MPa to 10 MPa, and the increase of the biggest differential settlement is not in inverse proportion to the decrease of compressive modulus, while presents slowdown trend; the biggest differential settlement increases from 6.38 cm to 13.10 cm with subgrade height increasing from 2 m to 8 m, because of the influence of boundary conditions, the smaller the subgrade height is, the closer the settlement curve of widening subgrade top is to "~".More>

2007, 7(1): 54-57.

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Analysis model of stress and deformation of permafrost subgrade with phase changing

Mao Xue-song, Li Ning, Wang Bing-gang,

Hu Chang-shun

Abstract: Based on the temperature field control equations of permafrost subgrade, the numerical two-dimension equations of its stress field and deformation field were put forward, the influence of water phase changing from moisture to ice on the instant deformation and creep deformation of soil was synthesized, the frost-heaving model of subgrade was experimented on january, the changing laws of the stress and deformation of permafrost subgrade surface were analyzed. It is pointed that the extreme stress and deformation of permafrost subgrade surface are determined by frost-heaving velocity within frost-heaving region; the maximum value of subgrade vertical displacement is at slope bottom, and deceases to the middle and the left boundary of subgrade little by little; with the increasing of frost-heaving velocity, the crack of subgrade surface tends to the middle of road from the slope bottom; the location of the maximum stress of subgrade surface is consistent with that of the maximum vertical displacement; road stress mainly lies in the phase changing region of moisture convergence. Analysis result shows that the phase changing of subgrade is the direct reason of subgrade frost-heaving damage, the analysis of the stress field and deformation field is an effective method to study the mechanism of permafrost subgrade damage.More>

2007, 7(1): 58-62.

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3-D thermal stress computation method of highway concrete box-girder

Peng You-song, Qiang Shi-zhong

Abstract: In order to improve the computation precision of 3-D thermal stress of concrete box-girder, the coupling relationship among thermal stress components caused by the effect of Poisson's ratio was taken into account, a computation method of thermal stress was proposed based on the theory of thermoelasticity, an integral property of thermal stress was deduced and used to effectively simplify the computation formulation of thermal stress, thermal stress was analyzed by simple structural analysis method, its practical computation formulas were derived. The results calculated by the method and formulas agree with those calculated by 3-D FEM, while the computation errors of conventional methods are more than 25%, which indicates the method and formulas are feasible.More>

2007, 7(1): 63-67.

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Calculating method of traffic zone radius in city based on inner trip proportion

Ma Chao-qun, Wang Rui, Wang Yu-ping, Yan Bao-jie, Chen Kuan-min

Abstract: With regard to the problem that taffic zone was divided through qualitative analysis in domestic cities, traffic zone dividing methods were analyzed in foreign and domestic cities, a calculating method of traffic zone radius was presented based on considering inner trip proportion. The calculation models of inner trip proportion were educed under three combinations between trip distance and traffic zone radius. The quantitative relationship among traffic zone radius, trip distance and inner trip proportion was gained by using VBA programme of Excel software. The range of traffic zone was confirmed according to appropriate inner trip proportion. Computation result shows that rational traffic zone radius in Xi'an ranges from 0.7 to 1.1 km, its real survey value is 0.9 km, inner trip proportion ranges from 5% to 10%, its real survey value is 9.28%. Obviously, the computation values are close to the real survey values, the method is feasible.More>

2007, 7(1): 68-72.

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Car-following model based on correlation analysis and safe headway

Zhang Hao-ran, Ren Gang, Wang Wei

Abstract: In order to accurately simulate car-following vehicles with different various dynamic performances, car-following experimental data and vehicles dynamic performances were analyzed, some variables were selected by regression analysis method, a new car-following model was established. The model was improved according to vehicles dynamic performances, so that car-following simulation result was compatible with vehicles dynamic performances; the model was revised according to the distances between vehicles, so that the model had applicability. Relative errors between the simulation values and experimental data of acceleration, velocity and position are respectively 6.0%, 0.1% and 1.0%, their correlation coefficients are respectively 0.863, 0.998 and 1.000. The result shows that the model accurately simulate motorcade behavior composed of vehicles with different dynamic performances, when the velocity discretenesses and gap discretenesses of vehicles are remarkable.More>

2007, 7(1): 73-75.

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Nonparametric microscopic simulation model of driving behavior

Wang Xiao-yuan, Yang Xin-yue

Abstract: Information mining technology was used to extract useful individual driving information from field measure data, driving sample database was established by amending and condensing field measure data, field measure data and redundant information were filtered by K nearest probability density function estimation method, a new simulation model of driving behavior was established based on nonparametric regression method. It is pointed that the real multi-resource information values of following vehicle are same as the simulated average values, and the field data swing around the simulated ones. Simulation result shows that appropriate smoothing parameter can improve the model accuracy, avoid the calibration limitation of giant sample data, and driving behavior can be reflected and forecasted in car-following process.More>

2007, 7(1): 76-80.

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Extended-two-step camera calibrated method of traffic accident scene measurement

Tang Yang-shan, Li Jiang, Bai Yan, Shi Jing

Abstract: In order to improve the data collection efficiency of traffic accidents, the properties of traffic accidents and camera calibrated methods were analyzed, a extended-two-step camera calibrated method applied in traffic accident scene measurement was put forward. In the method, camera was calibrated according to linear model, then its nonlinear parameters were modified based on considering lens aberration, at last image was emendated according to new parameters, full camera calibrated steps and procedure were put forward, and an experiment of accident scene photogrammetry was done. The calibration results of the extended method and linear method show that the maximum values of absolute errors and relative errors are respectively 10.9 and 1.7%, and the least values of them reach respectively 4.1 and 1.0%. Obviously, the extended method has high precision and stability.More>

2007, 7(1): 81-84.

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Simulation analysis for collision characteristics of concrete barriers on montane highway

Lei Zheng-bao, Yan Hai-qi, Zhou Ping-yan, Yu Jin-xiu, Zhou Zhi-gang

Abstract: In order to explore the collision characteristics of interrupted type and continuous type concrete barriers on montane highway, a integrated model of automobile-barrier-passenger-seat-safety belt was established by dynamic explicit finite element method(EFEM) and VPG software. The collision process analysis for four kinds of typical montane highway concrete barriers was carried out. It is pointed that when interrupted type concrete barrier is crashed by truck, concrete frusta blocks wheel, even right front wheel is divorced from truck, dummy's head and chest suffer from violent impact, and cab deformation is severe; however, when continuous type concrete barrier is crashed by truck, the hoist phenomenon of left rear wheel and the turning over trend of truck are obvious, but the height variety curve of truck tail shows that the hoist of left rear wheel does not continue over a certain height, and the wheel return to ground gradually, that's to say, the height variety trend of truck tail is stability; as the height of convex barrier flange at bottom is 80 mm, the front wheel of truck can smoothly climb up and slip away concrete barrier slope, but the rear wheel of truck can't climb up concrete barrier slope; while the height of convex barrier flange at bottom is 150 mm, the front wheel and rear wheel of truck can't climb up concrete barrier slope. Analysis result indicates that interrupted type concrete barrier is short of inducing ability to losing control vehicle, the convex flange of continuous type concrete barrier at bottom is too high to be climbed by truck, and it's necessary to optimize its main structure parameters.More>

2007, 7(1): 85-92.

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Equilibrium model of urban taxi service network

Bian Yang, Wang Wei, Lu Jian

Abstract: The operation characteristics of urban taxi service network were researched in order to determine the reasonable development quantity of urban taxis. A new equilibrium model of taxi service network was developed, the route-choosing behaviours of occupied and vacant taxis and the supply-demand equilibrium relation of taxi service network in deterministic demand condition were analyzed, so that the model could describe taxi drivers' searching behaviours and the relationships among road network, taxi quantity, drivers' searching time and passengers' waiting time. A solution algorithm was designed according to the model structure. The computation result of simple numerical example shows that the algorithm is convergent, the method is feasible, the model can determine the reasonable development quantity of urban taxis according to given passengers' waiting time, which may offer some beneficial guidance and theoretic basis to the planning and management of urban taxi network.More>

2007, 7(1): 93-98.

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Optimization algorithm of multi-truck multi-category goods loading based on benchmark methods

Liu Xiao-qun, Ma Shi-hua

Abstract: According to the ratio difference of volume and mass between trucks and goods, an optimization algorithm was designed by combinatorial theory on the basis of different benchmarks in order to make full use of the loading mass and volume of trucks. Light goods were marked with trucks' loading mass so as to promote the mass utilization rate of trucks, on the premise that the loading volume of trucks was fully used; heavy goods were marked with trucks' loading volume; even goods were marked with the ratio of volume and mass to optimize the trucks' loading volume and mass spontaneously, as both the dimension and load of goods were even relative to trucks. The comparison result between benchmark algorithm and other optimization algorithms shows that the efficiency of benchmark algorithm is prior to other algorithms, it has strong robustness, and especially fits to large-scale multi-truck multi-category goods loading.More>

2007, 7(1): 99-105.

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Method of solving vehicle routing problem with customers' dynamic requests

Li Bing, Zheng Si-fa, Cao Jian-dong, Yang Yang, Geng Hua, Lian Xiao-min

Abstract: A real-time vehicle routing problem(VRP) with customers' dynamic requests in logistics collection was decomposed into a set of static VRPs, in which vehicles were not at depot. Static VRPs were equally converted into general static VRPs by adding virtual customers and relative restrictions, and they were solved by static problem algorithm. With the solving VRP method, a dynamic VRP with 20 customers was solved by using improved saving algorithm. The result shows that the method is feasible, it takes 0.49 s to get the reoptimized route.More>

2007, 7(1): 106-110.

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Model and algorithm of vehicle routing problem under dynamic traffic

He Zhu-qing, Sun Lin-yan

Abstract: In order to optimize logistics delivery cost and consumer service level under dynamic traffic, transportation time was assorted into different distributions according to traffic, a mixed integer non-linear model of vehicle routing choice with time window constraints was set up to minimize logistics cost, a genetic algorithm with natural number coding was designed to solve the model, the simulation results of different delivery projects were compared. Comparison result shows that the algorithm is convergent, the logistics cost is reduced by 2%, the service level is improved by 5% to vehicle routing choice according to traffic condition.More>

2007, 7(1): 111-115.

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Pricing strategy of traffic information under double-objective route guidance system

Zhu Quan, An Shi, Xie Bing-lei

Abstract: In order to improve the precision of traffic information pricing, the travel time and travel cost of traveler were considered, a mixed-equilibrium pricing model of double-objective route guidance was established, the model was estimated and validated with numerical example, the comparative evaluation of the pricing strategies of single-objective and double-objective route guidances was carried out, the pricing result of double-objective route guidance was given. Computation result shows that single-objective route guidance changes the feasible region of traffic information pricing compared with double-objective route guidance, the respective interests of information users, information providers and traffic managers are taken as decision-making hosts separately, the traffic information pricings of the model are respectively 1.3, 2.6 and 1.8 RMB, which indicates that the mixed-equilibrium model is effective.More>

2007, 7(1): 116-121.

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Study of expressway public policies based on basic attributes

Yang Qi, Xi En-chong

Abstract: In order to make expressway public policies suit expressway development laws, the principles of highway economics and welfare economics were applied, the connotations of expressway public policies were analyzed, the natural monopoly attribute, common product attribute and external attribute of expressway were studied aimed to service perspective, some public policies of expressway were put forward according to its three kinds of basic attributes. Aimed at the natural monopoly attribute, the policy is to break blockaded market, rationally lead into competitive system, reinforce stimulation and restraint system, so that the effective supervision and management of expressway are carried out. Aimed at the common product attribute, the policy is to realize expressway privatization with inner restraint system for easing the deficiency of expressway construction fund. Aimed at the external attribute, the policy is to optimize expressway resource collocation by tax and the integration planning of expressway construction and land utilization. The policies can improve expressway public policies scientifically and objectively, and promote the rapid and stable development expressway construction and operation in China.More>

2007, 7(1): 122-126.

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