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19 April 2024, Volume 43 Issue 4 Previous Issue   
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Transportation Infrastructure Engineering
Transportation+Big Data & Artificial Intelligence
Transportation Equipment


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Transportation Infrastructure Engineering

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Elastic Buckling Stress of I-Shaped Corrugated Steel Web Girder under Non-pure Bending YANG Shuyan1， WANG Tianyu1， ZHA Zhixiang2， WANG Tao2 2024, 43(4): 1-6.  DOI: 10.3969/j.issn.1674-0696.2024.04.01 Abstract ( )   In the case of pure bending, a well-defined calculation formula exists for the buckling stress of I-shaped girders composed of flanged corrugated steel web (referred to as I-shaped CSW girder). However, this formula is not applicable under non-pure bending conditions. Numerical simulation study on cantilevered I-shaped CSW girders subjected to concentrated loads at the free end was carried out. The results indicate that the I-shaped CSW girder exhibits three kinds of buckling modes such as flange buckling, web buckling, and coupled buckling. When the buckling of the girder is dominated by the buckling of the flange plate, the buckling stress of the cantilever non-pure bending girder is greater than that of the pure bending girder. In this case, the width-to-length ratio of the flange is the primary factor influencing the buckling stress of the flange plate. Combined with numerous numerical simulation results, the buckling coefficient of the flange plate was revised and a formula for calculating the buckling stress of I-shaped CSW girder was proposed, which covered all buckling modes. References | Related Articles | Metrics

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Identification Technology of Structural Damages of Asphalt Pavement Based on Heterogenous Ground-Penetrating Radar Mapping HONG Xiaogang1， ZHANG Weiguang2， WANG Haoyang3， TIAN Hongbao4 2024, 43(4): 7-13.  DOI: 10.3969/j.issn.1674-0696.2024.04.02 Abstract ( )   The automatic identification method for asphalt pavement structural damage based on ground penetrating radar (GPR) mapping and deep neural network has the problem of limited data volume and unbalanced distribution of types, and the accuracy and stability of identification still need to be improved. The pavement structural damage identification technology based on heterogeneous GPR mapping was proposed. GPR was used to collect structural cracks and interlayer discontinuous diseases of asphalt pavement, and the measured profile maps was obtained. Based on the time-domain finite difference method, the echo features of cracks and interlayer discontinuities in the homogeneous model were numerically simulated, and combined with the measured maps to form dataset 1#. The "asphalt-aggregate" two-phase medium model was constructed based on the CT scan images of core samples, and the echo features of cracks and interlayer discontinuities in the two-phase medium model were simulated, which was combined the measured maps to form dataset 2#. YOLO v5 deep neural network was trained by dataset 1# and 2#, respectively. The research results show that the mAP@0.5 tested in YOLO v5 model using datasets 1# and 2# are 93.79% and 96.33%, which demonstrates that heterogeneous mapping features can enrich network training samples and improve the identification accuracy of deep learning model. References | Related Articles | Metrics

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Compaction Process Parameters of Cement Emulsified Asphalt Mixture Pavement ZHANG Cuihong1, DOU Yihua1,2, CAO Xuepeng3, HE Yutian1 2024, 43(4): 14-19.  DOI: 10.3969/j.issn.1674-0696.2024.04.03 Abstract ( )   In order to accurately predict the combination of compaction process parameters required for cement emulsified asphalt mixture pavement to achieve the target compactness, the numerical simulation and pavement compaction test were combined to carry out the research, which was based on the time-varying rheological characteristics of the mixture compaction and the compaction Bodner-Partom (B-P) constitutive model. Firstly, B-P material model was obtained by secondary development of ANSYS. Then, the B-P model parameters with periodic changes were substituted into the compaction combination simulation analysis. Finally, the pavement compaction test was carried out and the optimization combination of compaction process parameters was furtherly obtained. Numerical simulation results show that three combinations of low-frequency, high-amplitude and high-speed are obtained from the simulation results. With effect of the three combinations, the vertical strain value of the mixture decreases greatly along the direction of the wheel width, and the attenuation amplitude values of the vertical strain value of the mixture at the road depth of 6 cm are all small. The attenuation amplitude value of combination 6 is the smallest, and the target forming thickness of the road surface can be controlled below 7 cm. The pavement compaction test shows that the effective compaction energy of combination 6 (6 times of low-frequency, high-amplitude, and high-speed compaction) is relatively high. The number of compaction times of combination 6 should be optimized to 5 times of low-frequency, high-amplitude, and high-speed compaction as well as 2 times of high-frequency, low amplitude, and high-speed compaction. References | Related Articles | Metrics

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Performance Evolution Effect of Large-Void Asphalt Mixture in Cold Regions XU Junpeng1， ZHENG Chuanfeng2， BAO Chonghao1， SONG Zhenfeng1, LUO Haisong1 2024, 43(4): 20-29.  DOI: 10.3969/j.issn.1674-0696.2024.04.04 Abstract ( )   To clarify the damage patterns of large-void asphalt mixtures in cold regions, macroscopic damage tests were combined with microscopic quantitative analysis techniques (non-destructive CT scanning and Image Pro Plus (IPP) image processing technology) to analyze the performance and microscopic void structural characteristics of OGFC-13 and OGFC-16 under the effects of erosion, blockage, and freeze-thaw in cold regions. The results show that under the action of dynamic water erosion, the strength of the specimen with a porosity of 25% decreases significantly, with a maximum range of over 30%. In the extreme blockage test, the maximum blockage depth of the blockage reaches about 20mm, and the permeability coefficient after blockage is all less than 0.06cm/s. Under freeze-thaw action, the damage degree of the mixture increases with the number of cycles, while the damage degree of OGFC-13 is lower than that of OGFC-16 and shows the lowest at a porosity of 23%. Quantitative analysis of microscopic pore structure shows that the void fraction of the mixture can slightly increase under the action of freeze-thaw and erosion, but will significantly decrease under the effect of blockage. The change trend of pore quantity is opposite to that of porosity, and the pore characteristics are characterized by its equivalent diameter mainly ranging from 1.18 to 4.75 mm, accounting for about 50% of the void quantity. The macroscopic performance and microscopic evolution patterns of void structure of large-void asphalt mixtures in cold regions are obtained, which can provide technical support for the design of large-void mixtures in cold regions. References | Related Articles | Metrics

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Safety Analysis of Reservoir Dams Based on Cloud Model-Fuzzy FMECA Method CHEN Yongjiang1, WANG Kui1, ZHAO Mingjie1, 2, FAN Zhengqiang1 2024, 43(4): 30-36.  DOI: 10.3969/j.issn.1674-0696.2024.04.05 Abstract ( )   FMECA-fuzzy hierarchical analysis method evaluates the occurrence frequency and the impact degree of hidden dangers in reservoir dams and conducts risk assessment on dams by assigning weights and fuzzy comprehensive evaluation, which has certain scientific and practical significance. However, there are still deficiencies in reflecting the randomness of dam hazard factors and accurately reflecting the subjective preference of experts. Based on this, the safety analysis of reservoir dams based on the cloud model-fuzzy FMECA method was proposed. The evaluation matrix, weight matrix, and the corresponding comment sets in the FMECA-fuzzy hierarchical analysis method were inversely calculated to obtain the cloud model digital eigenvalues, and the risk evaluation result cloud model of the reservoir dam was obtained by the fuzzy evaluation. The corresponding comment set cloud model digital eigenvalues were determined according to the constraints, and then the cloud model of the dam risk assessment results and the cloud model of each comment set were simulated by MATLAB to achieve the safety assessment of reservoir dams. The proposed method was applied to a dam in Yunnan Province and the internal safety assessment level of the dam was A, which was consistent with the evaluation results of the on-site expert group. It is proved that the safety analysis of reservoir dams based on cloud model-fuzzy FMECA method is feasible and scientific to a certain extent. References | Related Articles | Metrics

Transportation+Big Data & Artificial Intelligence

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Highway Road Safety Risk Evaluation Based on Material-Element Extensible Combination Model ZHOU Hongwen1, FENG Xinmiao1, WANG Hong2, CHEN Xinxia1 2024, 43(4): 37-44.  DOI: 10.3969/j.issn.1674-0696.2024.04.06 Abstract ( )   In order to accurately determine the road safety level and figure out the key factors affecting road safety of highway during operation, a combined evaluation model of DEAMATEL-ISM and material element extension was proposed. Firstly, the initial index system was established based on road factors, and the Delphi method and sensitivity analysis were combined to select indicators and establish a comprehensive index system for highway road safety. The DEMATEL-ISM method was used to analyze the importance of each index, and a multi-level hierarchical structure model were constructed to understand the internal influence degree of each index, identify key influencing factors and calculate the initial weight of the index. And then the objective weights obtained by the entropy weight method were combined and optimized for weighting. Finally, the correlation degree was calculated through the material-element extendable model, and the security risk level of each index and the overall was obtained. The results show that the radius of horizontal curve, severe weather such as rain and snow, vehicle speed, traffic saturation, and longitudinal slope are key factors affecting the safety of highways. The proposed model is used to analyze three different sections of a highway in Henan Province, and it is found that section 1 and section 3 have higher safety, while section 2 has average safety. The evaluation calculation results are in line with reality, indicating that the constructed mathematical model is accurate and feasible. References | Related Articles | Metrics

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Evaluation of Arterial Coordination Effect Based on Inherent and Operational Reliability BAI Han1, WANG Xiuguang1, HUANG Hongke3, WANG Guojun2, YAN Xiang1 2024, 43(4): 45-51.  DOI: 10.3969/j.issn.1674-0696.2024.04.07 Abstract ( )   In order to alleviate the traffic congestion situation, many cities have implemented arterial coordinated control methods. However, this method lacks reasonable and effective demonstration and evaluation, resulting in poor effect. Based on the theory of product reliability, the basic concepts of inherent reliability and operational reliability were proposed. And the characterization parameters of driving speed, traffic flow, parking frequency and green wave bandwidth were also quantified. In addition, the evaluation membership functions of inherent reliability and operational reliability were proposed. Based on this, inherent reliability evaluation model and operational reliability evaluation model were established respectively, and a comprehensive evaluation system for arterial coordinated reliability was constructed. The inherent reliability and operational reliability before and after the implementation of arterial coordinated control were studied. Based on the actual measurement data of Yantai Road in Jinan, the practicality and scientificity of the proposed evaluation method were verified. References | Related Articles | Metrics

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Scheduling Optimization Model of Single Line Rail Transit Electric Feeder Bus YANG Yazao1,3， WU Zhao1,2， BIN Tao1,3 2024, 43(4): 52-59.  DOI: 10.3969/j.issn.1674-0696.2024.04.08 Abstract ( )   Passengers may encounter some problems such as long waiting time and high waiting cost when they transfer from rail transit to electric feeder bus. A timetable optimization method for electric feeder bus was proposed, which was oriented to passenger transfer in rush hour. By analyzing the transfer process, the minimum sum of four kinds of costs, namely the waiting time cost of transfer passengers, transfer failure cost, using cost and charging cost of electric buses, was taken as the objective function, and the departure order of electric bus, the waiting willingness of transfer passengers, and the influence of electric bus charging and discharging characteristics on the driving distance were taken as the constraint conditions. A mixed integer nonlinear programming model was constructed. In terms of transportation demand for feeder bus. The impact of changes in the travel demand of local passengers other than transfer passengers on the electric feeder bus schedule was also considered. Finally, the model was solved by using the hybrid artificial bee colony algorithm, and the sensitivity analysis of the algorithm was carried out by comparing with genetic algorithm and particle swarm algorithm. The results show that the total cost of the objective function is reduced by 23.56% compared with the original cost. The total cost is ￥1 355.32, among which the waiting time cost is ￥298.17, the transfer failure cost is ￥84.03, the bus company operating cost is ￥867.40, and electric bus charging cost is ￥105.71. The validity of the constructed model for the timetable optimization problem is verified. References | Related Articles | Metrics

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Operation Mode Optimization Method of Low Passenger Flow Bus HAN Yan 1, GUO Linfeng 2, ZHAO Hao 1 2024, 43(4): 60-66.  DOI: 10.3969/j.issn.1674-0696.2024.04.09 Abstract ( )   In order to solve the problem of low operational efficiency of traditional public transportation lines with low passenger flow, considering the spatial-temporal characteristics of passenger flow on low passenger flow public transportation lines, a combination service mode of traditional public transportation and DRT(demand response transit）were proposed, in which the optimization idea was the full time traditional bus mode (M1), segmented traditional bus + DRT mode (M2), and full time DRT mode (M3). The elements of different operation modes were analyzed. Considering the spatial and temporal characteristics of passengers, the station planning model was constructed based on three-dimensional spatial-temporal clustering. The cost of vehicle operation and passenger time were considered, with the goal of minimizing the total operating cost of each shift, a flexible DRT route and scheduling planning model with time windows was constructed, and genetic algorithm was used to solve the model. A bus line in Beijing was taken as an example to simulate and validate. The simulation results show that M2 reduces operational costs by 9.0% and 23.0% respectively compared to M1 and M3. The proposed method can provide technical reference for the formulation and optimization of operational plans for low passenger flow public transport services. References | Related Articles | Metrics

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High-Speed Overtaking Trajectory Planning Based on Multi-objective Optimization LIU Gang1，ZHANG Ze1，FAN Qun1，REN Hongbin2，YANG Xu3 2024, 43(4): 67-73.  DOI: 10.3969/j.issn.1674-0696.2024.04.10 Abstract ( )   In order to ensure the safety during the high-speed overtaking planning process and improve the comfort of the trajectory, a multi-objective high-speed overtaking trajectory planning algorithm was proposed. In the proposed algorithm, the boundary conditions for high-speed overtaking were solved based on a feasible convex space, and the feasibility of overtaking behavior was analyzed through a safe overtaking strategy. Then the goals such as trajectory smoothness and ride comfort were optimized according to the established overtaking trajectory planning objective function and comfort optimization function. Moreover, the proposed algorithm planned the trajectory in real time until the overtaking behavior was completed. In order to verify the effectiveness of the proposed algorithm, a joint simulation platform was built by Prescan and Matlab/Simulink to validate and analyze the two designed common overtaking scenarios. The simulation results demonstrate that, in scenarios involving constant speed overtaking and acceleration overtaking, the optimization effects of lateral displacement peak, lateral acceleration peak, yaw velocity peak, curvature peak, and speed peak of the overtaking trajectory are significantly enhanced through multi-objective optimization compared to single objective optimization. The comfort and safety of the planned overtaking trajectory are effectively improved. References | Related Articles | Metrics

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Truck Lane in the Connection Section of Urban Entrance and Exit WU Lan， LIANG Dong， ZHU Xingbei 2024, 43(4): 74-79.  DOI: 10.3969/j.issn.1674-0696.2024.04.11 Abstract ( )   To alleviate the passenger and freight congestion problem in the connection section of large logistics parks and the national highway caused by the rapid development of the logistics industry, starting from the traffic flow characteristics of the urban entrance and exit connection section, a calculation model for the length of the weaving area of truck lanes was established, according to the volumn and proportion of turning of trucks and buses at the intersection of the connection section. And the entrance lanes of intersections with different numbers of lanes were channelized. The calculation model for the length of the weaving area of truck lanes and the channelized scheme of entrance lanes were simulated and applied, which verified the feasibility of the weaving area length calculation model and the channelized scheme of intersection. References | Related Articles | Metrics

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Vehicle Identification Algorithms Based on Lightweight Neural Networks DENG Chao1,2,3,4, MA Junjie1, YAN Yi1, WANG Youfu1, LI Yanqi1 2024, 43(4): 80-87.  DOI: 10.3969/j.issn.1674-0696.2024.04.12 Abstract ( )   PDF (2237KB) ( )   lightweight neural network algorithm MobileNetV3-YOLOv5s based on hybrid attention mechanism was proposed to address the complex network structure, large parameter quantity, and high hardware requirements of current vehicle identification neural network algorithms. Firstly, the bneck module of MobileNetV3 was used to replace the backbone network of YOLOv5s. Secondly, the large convolutional kernel was replaced with a small convolutional kernel, and meanwhile, the SPPF algorithm was improved with a feature fusion method that required less computation. Finally, SENet and CAM algorithms were integrated into the backbone network to form a mixed attention module, which increased the network's weight on important regions. The experimental results show that on the UA-DETRAC dataset, the parameter amount of the proposed algorithm is reduced by 82.6% compared to YOLOv5s, only 2.34 MB, with an average identification rate of 98.2%. On the Nvidia Jetson AGX NX, the detection speed reaches 31 frames per second, with a speed increase of 10.7%. The proposed algorithm can be better deployed on edge devices and meet the requirements of autonomous driving. References | Related Articles | Metrics

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Dynamic Traffic Fault Data Recognition and Repair Based on Fixed Detectors SONG Yongchao, WANG Cui 2024, 43(4): 88-96.  DOI: 10.3969/j.issn.1674-0696.2024.04.13 Abstract ( )   In order to realize effective identification and repair of fault data, a fault data identification algorithm based on outlier distance detection and an improved DE-LSTM data repair model were proposed to address the problem that fixed detectors were prone to abnormal and missing traffic data during the collection of dynamic traffic data. By utilizing the inherent continuity of time series data, effective identification of fault data was achieved through direct outlier localization and outlier distance detection. The differential evolution algorithm was used to optimize the number of hidden layer neurons and the initial learning rate of long short-term memory neural network, and the adaptive control strategy was introduced to improve the mutation factor and crossover factor in the traditional DE algorithm. The repair model of long short-term memory neural network based on the improved differential evolution algorithm was established and compared with the fixed threshold combined with traffic flow mechanism, LSTM neural network model and DE-LSTM repair model. The example verification results indicate that compared with the fixed threshold combined with traffic flow mechanism method, the outlier distance detection algorithm has a more efficient recognition rate, and the improved DE-LSTM model has good computational efficiency and repair performance. References | Related Articles | Metrics

Transportation Equipment

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Ultimate Strength of Flat-Bar Stiffened Plate under Axial Cyclic Loading CUI Huwei1,2,3,4, FANG Wenwu1, DING Qiyin1 2024, 43(4): 97-103.  DOI: 10.3969/j.issn.1674-0696.2024.04.14 Abstract ( )   In order to study the influence of attached plate thickness, stiffener size and cyclic loading mode on the ultimate strength of flat-bar stiffened plates, the finite element software ABAQUS was used to carry out the numerical simulation of ultimate strength of flat-bar stiffened plates with different attached plate thicknesses and stiffener sizes under three axial cyclic loading modes, which was based on the initial deformation, welding residual stress, and Bauschinger effect. The research results show that when the attached plate thickness of the flat-bar stiffened plates is the same, the ultimate strength of the stiffened plate decreases with the increase of the stiffener size after cyclic loading, and the degree of decrease slows down. When the stiffener size is the same, the ultimate strength of the stiffened plate decreases with the increase of the attached plate thickness after cyclic loading, and the degree of decrease intensifies. When the amplitude of cyclic loading decreases from large to small, the ultimate strength of the flat-bar stiffened plate decreases the most. When subjected to constant amplitude cyclic loading, the ultimate strength of the flat-bar stiffened plate decreases the least after cyclic loading. References | Related Articles | Metrics

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Lifting Force Optimization of Damaged Shipwreck Based on Improved NSGA-Ⅱ CHENG Zhiyou1， XIE Jiahong1， LI Yaling2 2024, 43(4): 104-109.  DOI: 10.3969/j.issn.1674-0696.2024.04.15 Abstract ( )   In wreck salvage engineering, the lifting force parameters (location and size) arranged according to engineering experience can easily lead to larger internal forces (shear force and bending moment) of the damaged wreck in lifting, which may cause the lifting of wreck to break. Especially when the wreck is damaged, the possibility of lifting and breaking greatly increases. Therefore, starting from the theory of beam bending, a numerical calculation model of the internal force of the wreck was established according to the force characteristics during lifting, with lifting force parameters as the input and internal force distribution as the output. Based on the proposed calculation model, a lifting force parameter optimization model was established with the lifting force parameter as the optimization variable and the peak internal force as the optimization objective. The improved NSGA-Ⅱ algorithm was used for optimization and calculation. Taking a damaged shipwreck as the object, the modeling and optimization calculation were carried out by MATLAB. The results show that the peak value of shear force after optimization decreases by 22.72% and the peak value of bending moment decreases by 16.13%. References | Related Articles | Metrics

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Risk Characteristics of Air-Conditioner Operation with Full Touch Screen Mode under Urban Road Conditions WANG Chang, REN Miao, GE Zhenzhen, ZHAO Xia, LI Zhao 2024, 43(4): 110-116.  DOI: 10.3969/j.issn.1674-0696.2024.04.16 Abstract ( )   In view of the potential risks brought by the operation of the full touch screen air conditioner in the driving process, two types of driving experiment platforms, that is full touch screen and traditional human-machine interaction, was designed and established, with the typical urban road conditions as the object. The human-vehicle system data of 19 subjects during the air-conditioner operation process under the conditions of 40km/h and 60km/h were collected. The data were analyzed by one-way ANOVA and linear fitting. The results show that: compared with the button type, the total task duration (TTD) of the touch screen type is longer; the proportion of the single gaze duration (SGD) greater than 1.5s increases by about 20%, and the risk of vehicle operation is greater; the standard deviation of steering wheel angle (SDSWA) is smaller, which is close to 0. The single hand operation duration (SHOD) is proportional to the number of subtask steps. With the increase of vehicle speed, the proportion of the single gaze duration (SGD) of the subtasks in the button mode that is greater than 1.5s decreases by about 10%, and the risk of vehicle operation is reduced. There are no significant changes in the mean data of total task duration (TTD), the single gaze duration (SGD) and the single hand operation duration (SHOD). Therefore, with the popularization of full touch screen interactive interfaces today, the buttons for handling air-conditioner operation tasks should be retained, and the button layout or pressing effect should be optimized. References | Related Articles | Metrics