2009 Vol. 9, No. 5

Display Method:
Evaluation indices and methods of performances of preventive maintenance materials spraying on asphalt pavement
ZHANG Chao, WANG Chun-qing, YANG Shu-xiang, WANG Yu-shun
Abstract: In order to take advantage of the function of preventive maintenance materials spraying on asphalt pavement, five types of maintenance materials were studied in laboratory to establish their reasonable evaluation indices and evaluation methods according to their performance requirements, such as anti-aging property, water proofness, anti-slip performance, durability and oil resistance, etc.Analysis result shows that the remaining ductility ratio of asphalt before and after aging is better for representing the anti-aging performance of maintenance material; the permeability coefficient of fine maintenance material should reduce by over 80%;the anti-slip performance can be judged by whether the british pendulum number(BPN) is higher than the required standard; the durability and oil resistance can be evaluated by the change rules of the BPN after abbreviation experiment and the reducing degree of dynamic stability in rutting experiment respectively.More>
2009, 9(5): 1-6. doi: 10.19818/j.cnki.1671-1637.2009.05.001
Study of influence factors on tendons-soil interface characteristic
LING Tian-qing, ZHOU Bin, WU Chun-bo, ZHENG Zhi-neng
Abstract: A rib-reinforced slope in expressway's widening engineering was designed, in which holistic and unilateral polyethylene geogrid and steel-plastic composite geobelt were taken as enhancement materials and sand with fine-grained soil was taken as fill.The friction performance of tendons-soil interface was analysed by pull-out test in laboratory under different water contents and compactions.The enhancement effects of original geogrid, the one without horizontal ribs and reinforcement geobelt were compared.It is found that when the fill's water content is higher than its optimum moisture content, the tendons-soil interface strength reduces with the increase of water content, which is obvious.With the rise of the fill's compaction, the interface strength increases unceasingly and the reinforcement effect is distinct.The horizontal ribs' contribution rate to the interface characteristic of reinforcement soil is over 50%.More>
2009, 9(5): 7-12. doi: 10.19818/j.cnki.1671-1637.2009.05.002
Practical evaluation method of component reliability for existing concrete bridge
YAN Lei, LU: Ying-zhao, HE Shuan-hai, JIANG Jing
Abstract: In order to realize the rapid assessment of the reliability of existing concrete bridge, a loading effect probability model considering evaluation base period and the modification factor of live load was established.A classification evaluation criterion of component's bearing capacity was put forward, which regarded resistance coefficients and limit coefficients.Four main factors were taken into account, which are the bearing force situation, the determination degree of resistance, the ratio of vehicle load to dead load and the assessment reference period.A practical evaluation method of reliability for existing concrete bridge's component was put forward through a lot of reliability calculation.For an existing concrete bridge, the reliability index is 4.21 and the safety grade is secondary according to the computation method from unified standard for reliability design of highway engineering structures(GB/T 50283—1999).The checking index is 0.994 and the assessment result is also secondary.Computation result indicates that the method is convenient and practical.More>
2009, 9(5): 13-19. doi: 10.19818/j.cnki.1671-1637.2009.05.003
Spatial dynamic analysis of isolated bridges subjected to near-fault ground motion
WANG Tong-ning, LIU Jian-xin, YU Yong-bo
Abstract: With nonlinear dynamic time-history method, 3D dynamic responses of isolated bridge and non-isolated bridge were analyzed.Through comparing the dynamic responses of isolate bridge under the excitations of earthquakes with different frequency spectrums, the dynamic characteristic of isolated bridge was studied.Through comparing the longitudinal responses of isolated bridge with non-isolated bridge, the influence of near-fault ground motions on the seismic absorption ability of LRB(lead rubber bearing) was investigated.The result indicates that in contrast with common ground motion, the ratio of seismic absorption decreases from 54.4% to 18.3%, and the absorption effect of LRB reduces under near-fault ground motion.The longitudinal displacements of girders for isolated bridge and non-isolated bridge are 179.6 mm and 151.6 mm respectively.Obviously, LRB enlarges the displacement of girder and easily makes girder collide and fall, so LRB is not suitable isolated device for the bridges near fault area.More>
2009, 9(5): 20-25, 31. doi: 10.19818/j.cnki.1671-1637.2009.05.004
Distribution property of induced current for rail
WU Guang-ning, LEI Dong, DONG An-ping, WANG Wan-gang, AI Bing
Abstract: The mathematical model of induced current for rail was deduced by using infinitesimal method.On the basis of the real-time synchronous testing data of the Da-Qin Railway, the formation mechanism, distribution characteristic, influencing factors of induced current and its influence on rail voltage were analyzed in detail.Computation result shows that the error of the model is less than 10% and it can satisfy the engineering data requirements.The farther the distance between locomotive and traction substation, the bigger induced current becomes, whose distribution is great in the middle and little at both ends.The bigger damping constant is, the bigger induced current becomes, the faster its saturated velocity is.Induced current has effect to reduce rail voltage.The farther the distance between locomotive and traction substation, the more obvious the effect becomes.With the increasing distance, induced current can reduce the voltage by 55% at current enter point.More>
2009, 9(5): 26-31. doi: 10.19818/j.cnki.1671-1637.2009.05.005
Hunting motion and bifurcation behavior of six-axle locomotive based on continuation method
GAO Xue-jun, LI Ying-hui, GAO Qing
Abstract: A six-axle locomotive with simple nonlinearities was taken as the study object.The creep forces and the flange forces between wheels and rails in rolling contact were decided by the Vermeulen-Johnson creep force laws and piecewise function respectively.The hunting motion and bifurcation behavior of the locomotive running on ideal straight and perfect track were analyzed in detail.Based on tangent predictor, Newton iteration corrector and computing the entire solution branches step by step, a continuation algorithm was presented to calculate and track the limit cycles in the locomotive system.It is pointed out that an unstable periodic solution is bifurcated from a stable stationary solution when vehicle speed reaches 53.700 m·s-1, while the unstable periodic solution remains its stability when the speed reduces to 50.855 m·s-1.In the processes, the subcritical Hopf bifurcation can cause the jump and hysteretic phenomena of the oscillating amplitude.The result indicates that such nonlinear phenomena as the coexistence of some oscillations may appear in some either low or high speed range of the locomotive.More>
2009, 9(5): 32-36. doi: 10.19818/j.cnki.1671-1637.2009.05.006
Modeling and dynamics simulation of vehicle with linear induction motor
LIU Bin-bin, CENG Jing, LUO Ren, WU Ping-bo
Abstract: In order to research the dynamics performance of linear-motor metro vehicle and the suspension characteristics of linear induction motor(LIM), the classical electromagnetic mechanics model and finite element model of LIM, and the multibody dynamics model of the vehicle were established.The longitudinal and lateral end effects and air gap were taken into account in the classical model.Numerical method was adopted to solve the traction force, normal force and pitch moment of LIM.The solution results by the classical model were compared and verified by using finite element method.Simulation result shows that the classical model describes the mechanic properties of LIM and meets the requirement of dynamics simulation for metro vehicle.The dynamic performance of LIM is closely related to the change of air gap and suspension types.Different suspension types have their own advantages and disadvantages.Proper suspension type and air-gap control strategy can increase the stability of metro vehicle, reduce the wheel-rail wear and improve the curving performance of vehicle system.More>
2009, 9(5): 37-43. doi: 10.19818/j.cnki.1671-1637.2009.05.007
Control and test of vehicle semi-active suspension based on wheelbase preview
BEI Shao-yi, YUAN Chuan-yi, FENG Jun-ping
Abstract: In order to study the influence of wheelbase preview control technology on the performance of semi-active suspension system, a half-vehicle semi-active suspension model based on wheelbase preview was established. Neural networks and PID control theory were utilized, the control algorithm of single neuron adaptive PID was put forward, the single neuron PID control system of semi-active suspension based on wheelbase preview was designed, and the simulation was carried out. In order to study the effectiveness of the single neuron adaptive PID control strategy and the reliability of control system, vehicle road test was carried out. Analysis result shows that compared with the passive system, the peak and standard deviation separately decrease by 20. 91% and 19. 11% at the speed of 50 km·h-1, and decrease by 24.42% and 26.85% at the speed of 60 km·h-1, and the pitching angular aeeeleration is also reduced at a certain degree, so the vehicle ride performance is improved significantly.More>
2009, 9(5): 44-48. doi: 10.19818/j.cnki.1671-1637.2009.05.008
Optimization method of suspension parameters for articulated vehicle based on ride comfort and road-friendliness
ZHENG Zhong-lang, LU: Peng-min
Abstract: In order to investigate the influence of articulated vehicle's suspension system on ride comfort and road-friendliness and reasonably choose suspension parameters, a 7D dynamics model of 4-axle articulated vehicle was established.Taking the vertical acceleration of tractor and the dynamic load of every axle as object functions, a multi-objective optimization method of articulated vehicle's suspension parameters was put forward based on unified objective function method.After the optimization, tractor's vertical acceleration decreases by 21.43% and the maximal dynamic load of tractor's rear tire decreases by 17.72%.It is shown that using reasonable suspension parameters not only improves vehicle's ride comfort, but also reduces the dynamic load of truck acting on the road.More>
2009, 9(5): 49-54. doi: 10.19818/j.cnki.1671-1637.2009.05.009
Numerical simulation of engine bleeding brake
LUO Fu-qiang, HANG Jin, HE Ren
Abstract: In order to investigate the working process of engine bleeding brake, a numerical simulation model was built by computational fluid dynamics software Fluent. Its prescision was tested by using pressure curves. The pressure and flowfield of cylinder under bleeding brake were calculated. It is pointed that when exhaust valve lash is larger, the maximum pressure of cylinder and brake power are smaller in the working process of engine bleeding brake. At the beginning of compress process and the expand process, gas flows into cylinder from exhaust pipe. When engine speed is higher and exhaust valve lash is larger, the starting of flow backwards is earlier. The result indicates that the brake power of engine bleeding brake will increase if the choice of exhaust valve lash is reasonable.More>
2009, 9(5): 55-61. doi: 10.19818/j.cnki.1671-1637.2009.05.010
Image feature extraction from wavelet scalogram based on kernel principle component analysis
SUN Li-ping, CHEN Guo, TAN Zhen-zhen
Abstract: The scalogram image features of unbalance, misalignment, rub-impact and oil whirl fault were analyzed, and a new feature extraction method from the wavelet scalogram of fault signals was put forward based on kernel principle component analysis(KPCA).By using ZT-3 multi-functional rotor test bed, 32 samples for each type of fault were obtained, continuous wavelet transformation was carried out, and KPCA feature, scalogram texture feature and spectrum feature were extracted.Finally, the extracted features were tested and classified by using parameter self-adaptive support vector machine.Analysis result shows that the average recognition effect of features extracted by KPCA is up to 90%, and is higher than the classification results of scalogram texture feature and spectrum feature, so KPCA can effectively extract the features of scalogram and is helpful for the intelligent diagnosis of rotor faults.More>
2009, 9(5): 62-66. doi: 10.19818/j.cnki.1671-1637.2009.05.011
Planning method of basic road netwok based on ArcGIS
HU Xiao, WU Qun-qi, CHEN Xue, LU Xin-wei, JIANG Jing
Abstract: In order to sovle the bottleneck problem of road transportation of China, the scopes of main road network and basic road network in current road network.The influence of the construction expense and ground-occupied cost of highway, transportation cost, the service efficiency of road network on basic road network planning were studied.The transportation demand was taken as a planning target, which is in favor of the development of national economy and society.The planning model and algorithm promoted by above four factors were established and their integration software ArcGIS was developed.Analysis result shows that the service efficiency of basic road network after planning is in reasonable range of 70% to 80%, the ArcGIS system can reflect the volume and direction of transportation demand in studied area, so the ArcGIS system is feasible.More>
2009, 9(5): 67-72. doi: 10.19818/j.cnki.1671-1637.2009.05.012
Process neural network modeling for real time short-term traffic flow prediction
SONG Guo-jie, HU Cheng, XIE Kun-qing, PENG Rui
Abstract: In order to fully utilize the spatio-temporal process characteristic of traffic flow and predict traffic flow in real time, both process neural network and the online learning technology of data stream were imported into short-term traffic prediction. Considering the inherent traffic features of daily-periodicity and weekly-periodicity, process neural network and wavelet transform were combined to deal with the multi-scale process characteristic of historical data. A road network prediction model was constructed, and was optimized by adopting principal component analysis and utilizing the influence of traffic flow space similarity. An online learning algorithm was proposed based on Hart wavelet technology, which has the characteristics of selfadaptability and real-time prediction. Experimental result shows that the forecasting accuracy of the model is better than ordinary neural networks, its relative error of mean percentage reduces by 6%-8%, and its prediction time reduces by 67% at least, so the model has good performance and can meet the demand of real-time prediction of short-term traffic flow.More>
2009, 9(5): 73-77. doi: 10.19818/j.cnki.1671-1637.2009.05.013
Hybrid evacuation population estimation model based on fuzzy logic and discrete choice model
AN Shi, CUI Jian-xun, WANG Jian
Abstract: In order to predict the personnel decision behaviors in potential dangerous areas about participating evacuation or not reasonably, a hybrid model was presented based on fuzzy logic and discrete choice model, which could reflect the influencing factors and degrees for evacuation decision behavior.The binary Logit model structure was used to construct the hybrid model, and fuzzy logic was adopted to capture subjective and qualitative variables.Based on the analysis of significance, the influencing factors of evacuation decision behavior and their responsible coefficients in utility function were determined.The evacuation behavior surveying data after hurricane Andrew in America were used to estimate and test the hybrid model, and its result was compared with that of relative models.Analysis result indicates that the prediction accuracy of the hybrid model reaches 85%, so the hybrid model has a higher fitting degree and a better prediction efficiency.More>
2009, 9(5): 78-82. doi: 10.19818/j.cnki.1671-1637.2009.05.014
Calculation model of inland waterway transit capacity based on ship-following theory
ZHU Jun, ZHANG Wei
Abstract: In order to make sure the scale and layout of inland waterway reasonably, the connotation of waterway transit capacity was analyzed. The functional relationship between space headway and vessel velocity was studied by using optimization principle and nonlinear shipfollowing theory, and the calculation model of waterway transit capacity was established from microscopic view. The model was validated combined with the data of different grade waterways, and its result was compared with that of other models. Comparison result shows that the transit capacities of waterways from grade 2 to grade 5 are 11.42× 104 t, 5.72 × 104 t, 3.66× 104 t and 2.75 × 104 t respectively, which are close to the results of other models, so the calculation model based on critical space headway and critical velocity can accurately compute the waterway transit capacity.More>
2009, 9(5): 83-87. doi: 10.19818/j.cnki.1671-1637.2009.05.015
Grey residual error model of highway traffic accident forecast
LI Gang, HUANG Tong-yuan, YAN He, HUANG Xi-yue
Abstract: Grey residual error model (GREM) was proposed to improve the prediction accuracy of highway traffic accidents with high randomicity. GREM was used to depict the accident prediction values piecewise with the linear superposition of multiple exponential functions, and it overcomed the shortcomings of grey model(GM). GM was only able to describe the monotonous change process and only could be used to estimate the sequences consistent with obvious exponential law. The manifold factors affecting GREM were analyzed and concluded in detail, including amending objects, data selection, data pretreatment and amending methods. Then, 4 practical GREMs were summed up. Analysis result indicates that in comparison with GM, all GREMs' predicting errors reduce by 70%- 80%, and the one modeled by residual error directly and restored only one time has low complexity and its predicting error is less than 5%.More>
2009, 9(5): 88-93. doi: 10.19818/j.cnki.1671-1637.2009.05.016
Multifactor prediction model for traffic accident based on grey-radial basis function neural network
LIU Zhao-hui
Abstract: In order to realize the traffic accident prediction under various road factors, a muhifactor prediction model based on grey-radial basis funetion(RBF) neural network was put forward, which combined grey system theory with neural network theory. Grey theory could improve the utilization of available information and weaken the undulation of data sequence. Neural network had the processing ability of nonlinear adaptability information. The muhifactor prediction model was compared with different prediction methods by a case. Analysis result shows that in comparison with grey prediction and RBF neural network prediction, the mean absolute error and mean absolute percent error of muhifaetor prediction model decrease by 50% and 12.5%, the Theil coefficient decreases by 54.5% and 16.6%, the validity increases by 2.7% and 0.3% respectively, so the combined prediction method can improve the efficiency of system modeling and the precision of prediction model.More>
2009, 9(5): 94-98. doi: 10.19818/j.cnki.1671-1637.2009.05.017
Dynamic congestion pricing model of combined travel with elastic demand in multi-class network
ZHANG Hua-xin
Abstract: The dynamic congestion pricing problem of combined travel was studied in multi-class network with elastic demand by using dynamic transportation assignment theory and stochastic utility theory. The assumptions that all users were homogeneous and total travel demands were all the same were released. A variational inequity model satisfying the dynamic combined travel conditions was proposed, a bi-level dynamic congestion pricing model was established and its solution algorithm was designed. Analysis result shows that the congestion pricing is very effective to reduce the departure rate during peak hours by means of transferring some flows from peak hours to off-peak hours. It has greatest impact on the travelers with low values of time because these travelers would probably change their departure time choices and route choices to avoid the payment of congestion pricing. The total social welfare increases after the implementation of congestion pricing, so the congestion pricing can improve the congestion situation of some links and optimize the whole service efficiency of traffic system.More>
2009, 9(5): 99-105. doi: 10.19818/j.cnki.1671-1637.2009.05.018
Calculation method for transit period of railway freight under speed-raising condition
ZHU Chang-feng, LI Yin-zhen
Abstract: The problems existing in present calculation methods of transit period were analyzed, the daily average running tariff kilometer of each kind of freight transport product was analyzed under speed-raising condition, and its statistical results were examined by adopting χ2 testing method.A new transit period calculation method for railway freight under speed-raising condition was put forward, the value range of each parameter was determined according to statistical results and relative references.The method could be dynamically adjusted based on freight-product category and the railway line condition of transport section.Analysis result shows that the daily average running tariff kilometer of each kind of freight transport product obeys normal distribution; the maximum difference value between the transit period calculated by present method and the practical forwarding time of freight is 4.5 d, while it is only 0.8 d by adopting the new calculation method, so the method can objectively respond the forwarding time of each kind of freight transport product under speed-raising condition.More>
2009, 9(5): 106-110. doi: 10.19818/j.cnki.1671-1637.2009.05.019
Multi-attribute combinatorial auction model and algorithm for container shipping service
YANG Hua-long, DONG Fang, ZHENG Bin, JI Ming-jun
Abstract: In order to solve the problem of high transaction cost in container shipping service, the combinatorial auction approach of container shipping service was pointed out.Freight rate, carrier's service quality, reputation and network coverage capacity were selected as criteria to determine the combinatorial auction winner in container shipping service from shipper's perspective.A multi-attribute combinatorial auction model for container shipping service was established and decomposed into 4 single objective programming models.An objective programming algorithm was given out based on Euclid distance.Simulation result shows that the utility value of multi-attribute combinatorial auction increases by 2.429 compared with that of selecting one carrier, so the model and algorithm are feasible.More>
2009, 9(5): 111-115. doi: 10.19818/j.cnki.1671-1637.2009.05.020
Driver's conflict avoidance decision model based on preemptive level
XIAO Yong-jian, YANG Jian-guo, WANG Zhao-an
Abstract: Vehicles' crossing behaviors were analyzed from the perspective of conflict avoidance, their decision rules during crossing process were described by using field graph tool, and a driver's conflict avoidance decision model based on preemptive level was introduced, which was different with the conventional gap acceptance model.The distribution parameter of drivers' critical preemptive level threshold was calibrated by field conflict data, and statistical hypothesis was tested through Kolmogorov test method.Analysis result shows that among 437 groups of field conflict samples, 82.2% drivers' decisions are normal decisions, while 17.8% drivers' decisions are abnormal decisions, which indicates that there should be a physiological critical preemptive level, and the drivers' critical preemptive level threshold follows normal distribution N(0, 0.22).More>
2009, 9(5): 116-120. doi: 10.19818/j.cnki.1671-1637.2009.05.021
Factor analysis and fuzzy clustering of driver behavior pattern
ZHANG Lei, WANG Jian-qiang, YANG Fu-rui, LI Ke-qiang
Abstract: In order to study driver pattern and population clustering feature, driver behavior self-reported investigation for normal drivers was conducted with standardized driver behavior questionnaire(DBQ), and its validity and reliability of the questionnaire were verified based on statistics analysis.Driving ability factor and driving style factor were extracted from the questionnaire results to quantify driver characteristics with factor analysis method.Based on fuzzy C-means clustering algorithm, driver cluster distribution was established with the two factors as pattern features.Comparison result indicates that the higher the driving ability factor value is, the weaker the driving ability is; the higher the driving style factor value is, the more aggressive the driver style is.The clustering result has similar distribution tendency with driver subjective evaluation, and the clusters with weaker ability or more aggressive style have higher accident driver rate.More>
2009, 9(5): 121-126. doi: 10.19818/j.cnki.1671-1637.2009.05.022