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26 October 2022, Volume 41 Issue 10 Previous Issue    Next Issue
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Transportation+Big Data & Artificial Intelligence
Transportation Infrastructure Engineering
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Transportation+Big Data & Artificial Intelligence

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Status and Progress of Highway Safety Evaluation Based on CarSim Software HUANG Xiaoming1,2, HONG Zhengqiang1,2 2022, 41(10): 1-6.  DOI: 10.3969/j.issn.1674-0696.2022.10.01 Abstract ( )   PDF (2225KB) ( )   As an important content and link of road design, road safety evaluation has always been paid attention to by road design and management departments. In the past, the design consistency and other indicators were mainly relied on in road safety evaluation, and dynamic simulation of design results was seldomly carried out. CarSim, as a professional software combining vehicle dynamics and road reality, was widely used in the field of vehicle engineering. At the same time, more and more researchers in the field of road engineering began to use this software for their own professional research. The current situation and development trend of the application of CarSim software in road engineering safety evaluation at home and abroad were summarized, and the practicability and applicability of safety evaluation technology based on CarSim and other software in the field of road engineering were discussed. The integration of road safety and vehicle driving characteristics is an inevitable trend of road design evaluation, and the organic combination of people, vehicles and roads and the future demand direction still need to be explored in depth. References | Related Articles | Metrics

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Comprehensive Utility Evaluation and Influence Mechanism of Traffic Safety Facilities in Tunnel Based on Driving Simulation ZHAO Xiaohua1, DONG Wenhui1, JU Yunjie1, ZHANG Changfen2, YIN Jizhou3 2022, 41(10): 7-15.  DOI: 10.3969/j.issn.1674-0696.2022.10.02 Abstract ( )   PDF (656KB) ( )   In order to reduce tunnel traffic accidents, the comprehensive effect of highway tunnel traffic safety facilities (traffic safety facilities for short) was studied. Traffic safety facilities such as white reflective rings, color reflective rings, contour marker and protruding road sign were set in the tunnel. Based on driving simulation technology, the driving behavior and visual characteristics were obtained, and the matter-element model was used to evaluate the comprehensive effectiveness of different facilities. Moreover, on the basis of the optimal comprehensive utility scheme (white reflective ring), the layout parameters of the white reflective ring were studied, and a linear mixed effect model was built to explore the influence mechanism of multiple factors on driving behavior. The research results show that in a 3 km tunnel, the layout of reflective ring will affect the drivers driving safety and comfort to a certain extent, but the layout of reflective ring at 200m and 400m intervals can effectively relieve the drivers psychological tension, which lays a theoretical foundation for the further formation of the guidance for the setting of tunnel traffic safety facilities from the driver level. References | Related Articles | Metrics

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Station Importance of Urban Rail Transit Network Based on Complex Network and VIKOR JIAO Liudan1, LUO Min1,2, CHEN Weiwei1, WU Ya3 2022, 41(10): 16-25.  DOI: 10.3969/j.issn.1674-0696.2022.10.03 Abstract ( )   PDF (931KB) ( )   As a typical complex network structure of urban rail transit, it is of great significance to strengthen the management of important stations to ensure the connectivity and operational efficiency of the entire urban rail transit system. Based on the complex network theory, Space-P method was selected to build the topological structure model of rail transit network. The centrality of passenger flow and station property were added on the basis of three centrality indexes such as point degree centrality, closeness centrality and betweenness centrality, and the station importance ranking model of rail transit stations was constructed by variation coefficient method and VIKOR method. Then, taking Chongqing rail transit as an example, an empirical analysis was carried out, and the importance of 141 stations in the network was sorted and analyzed. The research results show that: Hongqihegou station is the most important station among 141 stations and in 8 lines. References | Related Articles | Metrics

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Route Optimization of Multi-distribution Centers Considering Time andSpace Congestion and Time Window CHEN Yanyi, HOU Huabao 2022, 41(10): 26-34.  DOI: 10.3969/j.issn.1674-0696.2022.10.04 Abstract ( )   PDF (628KB) ( )   In the fresh food distribution path optimization problem, it has the characteristics of high demand for product timeliness and uncertain distribution time, and gradually becomes large scale and multiple distribution center. Comprehensively considering the customer time window, the preservation period of goods, the spatial-temporal characteristics of road network congestion and multiple distribution center, a multi-yard and multi-vehicle fresh distribution route optimization model was constructed, which considered the comprehensive fuzzy time window and speed space-time coefficient. An improved ant colony genetic algorithm (ACO-GA) was proposed, in which the successive modification algorithm on both sides and the orthogonal test design were embedded in the traditional ant colony genetic algorithm. And the orthogonal experimental design was used to optimize the algorithm parameters, so as to improve the calculation ability of the algorithm. The Solomon examples with different distribution characteristics were used to reflect the customer groups with different aggregation forms. Finally, the proposed model was compared with other models, and the rationality of the model was verified. And the proposed algorithm was compared with the traditional algorithm to verify the effectiveness of the proposed algorithm. The results show that the proposed model can better solve the contradiction between high timeliness and uncertain delivery time, and the computational ability of the algorithm is acceptable. The research results can provide new ideas for lean distribution of fresh products. References | Related Articles | Metrics

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Multi-step Prediction of Individual Travel Based on Deep Attention Model WENG Xiaoxiong1, REN Jie1, QIN Zhenlin1, LUO Ruifa2 2022, 41(10): 35-40.  DOI: 10.3969/j.issn.1674-0696.2022.10.05 Abstract ( )   PDF (459KB) ( )   For a long time, the prediction of individual travel has been the focus of research in the field of transportation. Aiming at the limitations of current research on individual travel, a sequence-to-sequence model with attention mechanism was used to predict individual travel in multiple steps. Firstly, the embedded vectors of individual travel characteristics were fused by word embedding method. And then three kinds of individual travel multi-step prediction models were designed on the basis of the sequence to sequence model with attention mechanism, such as the overall output model, the step output model and the multi-model combined model. The proposed models were compared with the traditional model. Finally, the influence of different prediction steps on the experimental results was explored, which verified the applicability and superiority of the sequence-to-sequence model with attention mechanism in multi-step prediction. References | Related Articles | Metrics

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Travel Passenger Demand Forecast Model Driven by Social Network Data CHEN Jian, PENG Tao, CAO Yanshi, LIU Keliang 2022, 41(10): 41-47.  DOI: 10.3969/j.issn.1674-0696.2022.10.06 Abstract ( )   PDF (3400KB) ( )   In order to solve the problem of insufficient accuracy caused by limited data sources of tourism passenger demand forecasting model under the new information environment of mobile internet, the text data related to travel in social networks were collected through web crawler technology, which took social network data as an entry point. Then, the sentiment analysis of BERT model was used for quantitative processing of social network text data. The structured social network data was integrated into the traditional tourism passenger transport demand forecasting model, and the gradient boosting regression tree (GBRT) based tourism passenger transport demand forecasting model was built with the combination of variables such as weather and holiday state. At last, taking Huangshan scenic area as an example, based on the actual statistical data and social network data of the passenger station in the scenic spot, the above methods were used to make an empirical analysis of Huangshan tourist passenger demand forecast. The results show that the social network data is helpful to improve the accuracy of tourism passenger transport demand prediction. The average prediction accuracy of the tourism demand prediction model based on social network data is 10.81% higher than that of the traditional model. References | Related Articles | Metrics

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Willingness to Participate in Freight Crowdsourcing of Intercity Private Vehicle Travelers DAI Quan, LIU Changping, LIANG Kun 2022, 41(10): 48-53.  DOI: 10.3969/j.issn.1674-0696.2022.10.07 Abstract ( )   PDF (570KB) ( )   In order to identify the influencing factors of the willingness of intercity private vehicle travelers to participate in freight crowdsourcing, nine hypothetical situations with four attributes and twelve levels were designed by the orthogonal method, and the SP questionnaire was designed. By use of SPSS 20 software, the conjoint analysis method was used to analyze the respondents preference for crowdsourcing conditions, and the influence degree of each attribute on the respondents preference. Correlation analysis and ordered multi-class Logistic model were used to carry out the regression analysis on the influence of respondents environmental protection awareness, social characteristics and other factors on their willingness to participate in crowdsourcing. The results show that compared with the two factors of traceability and transportation insurance, the respondents are more concerned about the convenience of handover of goods and the rewards obtained in crowdsourcing activities; the respondents willingness to participate in crowdsourcing is positively related to their environmental protection awareness and education level, and negatively related to their annual household income. References | Related Articles | Metrics

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Container Throughput Prediction of Qingdao Port Based on Multivariate LSTM Model WANG Fengwu, ZHANG Xiaobo, JI Zhe, WANG Le 2022, 41(10): 54-61.  DOI: 10.3969/j.issn.1674-0696.2022.10.08 Abstract ( )   PDF (586KB) ( )   In order to predict the port container throughput more scientifically and accurately, a multivariate input LSTM model was established based on the long and short-term memory network (LSTM) model in the deep learning method. Firstly, the hierarchical clustering method was used to carry out the cluster analysis of multiple influencing factors of container throughput of Qingdao port. According to the calculated value of Pearson’s correlation coefficient, typical influencing factors were selected. Secondly, combined with the historical container throughput data, it was input into the model as a multivariate for prediction, and the prediction results was compared with those of the univariate LSTM model and the traditional prediction model ARIMA model. The results show that the prediction error of the LSTM model using influencing factors and historical throughput data as multivariate input is reduced, the mean absolute percentage error (MAPE) is reduced to 4.170%, and the root mean square error (RMSE) is reduced to 7.736. Therefore, the predicted value is more accurate. The proposed model improves the scientificity and accuracy of prediction and promotes the application of deep learning technology in port container throughput prediction, which can provide references for reasonable decision-making and planning for ports. References | Related Articles | Metrics

Transportation Infrastructure Engineering

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Flexural Behavior of CFRP Strengthened RC Beams under Coupling Action of Load and Hygrothermal Environment YAO Guowen1,2, LIU Mingxu2, WU Shuhang2, CHEN Xuesong2 2022, 41(10): 62-68.  DOI: 10.3969/j.issn.1674-0696.2022.10.09 Abstract ( )   PDF (1369KB) ( )   In order to investigate the long-term performance of carbon fiber reinforced plastics (CFRP) reinforced bridge structures in service environment, the accelerated corrosion experiments of RC beams strengthened by CFRP under different load types coupled with hygrothermal environment were carried out. Under three working conditions of no-load, static load and alternating load coupled with hygrothermal environment, the stress, deformation, bending capacity and damage evolution law of the test beam were discussed, and the damage mode of the beam body and the bond interface was analyzed. The transfer rule of shear stress at CFRP bonding interface was revealed by microelement analysis. The results show that the plasticization of the adhesive layer and the hydrolysis of the matrix are the main causes of the deterioration of the bonding interface properties under the coupling action of load and hygrothermal environment. The coupling action of load and hygrothermal environment, especially the alternating load, promotes the deterioration of the adhesive layer and causes the further deterioration of the mechanical properties of the reinforced structure. The load coupling effect increases the transfer rate of shear stress from the bonding interface to the end of the beam. The coupling effect of alternating load and hygrothermal results in the reduction of ultimate bearing capacity, mid-span deflection and ultimate strain of CFRP strengthened RC beams by 16.8%, 38.3% and 28.3%, respectively. References | Related Articles | Metrics

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Bonding Performance of CFRP-Concrete Interface after Temperature Cycling ZHAO Shaowei, REN Ziwei, GUO Rong, ZHANG Jiahe, CHEN Bing 2022, 41(10): 69-76.  DOI: 10.3969/j.issn.1674-0696.2022.10.10 Abstract ( )   PDF (2123KB) ( )   Firstly, 36 specimens after temperature cycling were subjected to double shear tests. Secondly, the influence of factors such as temperature cycles, concrete strength and CFRP slab width and thickness on interface bonding performance was analyzed. Finally, based on the fitting of Monti bilinear model, the interface bond-slip constitutive model under the action of temperature cycling was obtained. The results show that with the increase of the number of temperature cycles, concrete strength grade and CFRP board width and thickness, the maximum interface shear stress τmax increases in varying degrees. Among them, the number of temperature cycles has a significant impact on it, but as the number of temperature cycles increases, the increase of the maximum interface shear stress τmax shows a slowdown trend. The fitting values of the bond-slip constitutive model are in good agreement with the test results, and the modified model has high reliability. References | Related Articles | Metrics

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Tensile Properties of Section Steel-UHPC Composite Deck Structure MAO Qiyuan1,2, SHAO Xudong1,2, LIU Menglin3, SHEN Xiujiang1,2, LI Yuqi1,2 2022, 41(10): 77-85.  DOI: 10.3969/j.issn.1674-0696.2022.10.11 Abstract ( )   PDF (1637KB) ( )   Uniaxial tensile tests were conducted on four full-scale strip model members of the section steel-UHPC composite deck structure (two deck members composed of UHPC+section steel and two joint members composed of UHPC+section steel+steel bar). The strain and crack development law of the member was analyzed. ABAQUS software was used to establish the finite element model and simulate the whole test process, and the development law of the axial deformation of members and the strain of section steel and steel bar were analyzed. The results show that, for the deck members, the section steel and UHPC thin plate have good cooperative mechanical performance, and the tiny cracks are densely distributed until the section steel yields, and 2～3 main cracks are generated in the UHPC thin plate. For the joint members, as the loading progresses, the initial microcracks appear at the interface between the new and old UHPC, and the subsequent microcracks are mainly concentrated at the lower step until the steel bar embedded in the lower step yields; the joint member is damaged, and a single main crack is formed at the lower step. For the UHPC axial deformation value of deck members and joint members, the section steel strain value of deck members or the steel bar strain value of joint members, the ABAQUS calculation results are in good agreement with the test results. References | Related Articles | Metrics

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Calculation and Analysis of Equivalent Rectangular Stress Parameters of Concrete Circular Members ZHANG Shengping1, CHEN Xu2, CHU Xiujuan1 2022, 41(10): 86-92.  DOI: 10.3969/j.issn.1674-0696.2022.10.12 Abstract ( )   PDF (614KB) ( )   In order to solve the problem of large error when the constant value parameters of equivalent rectangular stress model in the code were used for circular section, the analytical solution of equivalent rectangular stress model parameters of circular section was derived. Based on the stress-strain constructive relationship in code, and according to all possible strain distributions in the axial-bending bearing capacity limit state, the analytical solutions of the stress full coefficient and resultant force position coefficient of the circular cross-sectional equivalent rectangular stress model were derived on the principle of equivalence. The calculation flow of analytical solution of bending and compression bearing capacity of arch concrete in compression zone was given. The analytical solution was verified by the numerical solution of strip method. The research shows that the position of the resultant force of the circular section concrete changes slightly and approaches to the centroidal axis. The safety requirements for vertical load-bearing small eccentric compression members are high, and the bearing capacity of small eccentric compression zone cannot be accurately calculated by the constant value parameters, so it should be calculated according to the analytical solution. References | Related Articles | Metrics

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Grading Assessment of Steel Corrosion Based on Spontaneous Magnetic Flux Leakage Effect ZHOU Jianting, XIA Qianwen, YANG Mao, ZHANG Hong, JIANG Hejing 2022, 41(10): 93-99.  DOI: 10.3969/j.issn.1674-0696.2022.10.13 Abstract ( )   PDF (1059KB) ( )   In order to accurately detect and evaluate the corrosion of steel bars, 40 groups of corrosion grading evaluation tests of HRB400 steel bar with different diameters were carried out, which was based on the spontaneous magnetic flux leakage detection technology. The relationship between different corrosion degrees α and magnetic induction intensity By, Bz was analyzed. The quantitative relationship between the corrosion degree α and the magnetic characteristic indexes β and γ of the steel bar specimens was mainly explored, and the evaluation system between the corrosion grade of the steel bars and the magnetic characteristic indexes β and γ was established. And the credibility of the proposed evaluation system was verified. The research results show that when the lift-off height is constant, the magnetic characteristic index values β and γ have a strong correlation with the corrosion degree α of the steel bar specimen. And with the increase of the rust degree α, the magnetic characteristic index values β and γ show an overall increasing trend, but both have a certain degree of dispersion. Based on this, the steel corrosion degree α is divided into 4 grades. Through the establishment of different evaluation systems, it is found that the comprehensive discrimination accuracy of the magnetic characteristic indexes β and γ reaches 92.5%. The support vector machine (SVM) statistical learning algorithm is introduced to evaluate the proposed evaluation system, and its accuracy rate reaches 90%, which proves the credibility of the proposed evaluation system. References | Related Articles | Metrics

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Gas Distribution and Movement Rule under Combined Action of Temperature and Humidity in High Gas Tunnel WANG Linfeng1, ZHONG Yihong1, LI Ming2, ZHOU Nan1, YANG Liu1 2022, 41(10): 100-107.  DOI: 10.3969/j.issn.1674-0696.2022.10.14 Abstract ( )   PDF (1379KB) ( )   In the process of gas tunnel boring, the heat emitted by various tunneling equipment and the high heat and high humidity environment caused by the use of wet cooling and dedusting equipment will have an impact on the movement law of harmful gases such as gas. Controlling the temperature and humidity of the tunnel environment in an appropriate range can not only improve the comfort of workers, but also help reduce the gas concentration along the length of the tunnel. Taking Jimingshan Tunnel as an example, the distribution law of gas in the tunnel and the influence of temperature and humidity environment on gas distribution in the tunnel were studied by using numerical simulation software such as Fluent, and the optimization range of temperature and humidity values was proposed. The results show that the change of temperature and humidity environment will not significantly change the distribution law of gas along the tunnel length. Only increasing the humidity value in the working area will reduce the gas concentration along the way. Only increasing the temperature value in the working area will cause the gas near the face of the tunnel to gather at the bottom. Under the combined action of temperature and humidity, the gas concentration at the bottom of the tunnel is higher than that at the top of the tunnel. Finally, the optimal humidity value of tunnel working environment is obtained by considering the optimal comfort level of human body and construction safety. References | Related Articles | Metrics

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Fast Detection Technology for Tunnel Slab Staggering Based on Oblique Line Structured Light LIU Xingen1,2, CHEN Yingying1,2, LI Mingdong1 2022, 41(10): 108-115.  DOI: 10.3969/j.issn.1674-0696.2022.10.15 Abstract ( )   PDF (2904KB) ( )   In order to realize the rapid and automatic detection of tunnel slab staggering and ensure the safety of tunnel structure, a fast-detecting method for tunnel slab staggering based on oblique line structure light was proposed. Firstly, based on the principle of oblique laser triangulation and imaging, the theoretical formula for calculating the amount of misalignment was derived. And the random sampling consistency (RANSAC) algorithm was used for linear function fitting approximation to convert the angle parameters that were difficult to measure into function constants. Then, the region of interest (ROI) of the image was extracted by combining the target detection algorithm Yolo-v3 and the image gradient features. The sub-pixel level of the center of the light strip was extracted by gray square weighted center of gravity method. And the pixel displacement was obtained according to the distance formula between straight lines. Finally, the laboratory test data and actual engineering data were verified. The research results indicate that the algorithm Yolo-v3 can locate the tunnel slab staggering region, with an accuracy rate of 97.35% and a computational efficiency of 26 images per second. Meanwhile, compared with the extreme value method, the Steger method, and the gray center of gravity method, the proposed algorithm is more accurate in extracting the center of the light bar. Moreover, the absolute error of 87% of slab staggering detection results and actual measurement results is within 0.6mm, and the maximum absolute error is no more than 1.5mm. The proposed method can meet the engineering application. References | Related Articles | Metrics

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Influence of Screw Conveyor on Gradation Segregation for Asphalt Mixture ZHANG Chenguang, YE Min, ZHANG Zeyu, WANG Qi 2022, 41(10): 116-122.  DOI: 10.3969/j.issn.1674-0696.2022.10.16 Abstract ( )   PDF (3463KB) ( )   To accurately find out the cause of gradation segregation of asphalt mixture in paver screw conveyor and improve the pavement quality, the velocity and force models of the mixture under the action of the screw conveyor were firstly established, based on the screw conveying mechanism. And the dynamic characteristics of mixture in the conveying process were studied．Secondly, the distribution rule of aggregates with different particle sizes along the radial and axial direction of the spiral blade was analyzed, and the influence of the support hanger on the uniformity of the mixture transportation was studied. Finally, asphalt mixture pavement sampling and extraction screening test were conducted to verify the theoretical analysis conclusions. The research results show that the structure and operation parameters of the screw conveyor will affect the asphalt mixture distribution uniformity．The mixture axial velocity increases gradually from the center of screw blade along the radial direction．The average size of aggregates in the inner ring of screw blade are smaller than these in the outer ring. Fine aggregate easily tends to aggregate and segregate in the initial stage of the screw conveying process, and the segregation degree gradually weakens along the conveying direction. Coarse aggregate will aggregate and segregate after passing the critical point. The segregation degree is the largest at the support hanger area, which is manifested as coarse aggregate accumulation and segregation. The gradation test of asphalt mixture is consistent with the conclusion of theoretical analysis. References | Related Articles | Metrics

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Study on Mixing Parameters Based on Domestic Foamed Asphalt Cold Regeneration Equipment GUO Xiaohong1, WANG Jinqiao2, HUANG Weirong3, ZHOU Minxu2, SHAO Fazhan4 2022, 41(10): 123-129.  DOI: 10.3969/j.issn.1674-0696.2022.10.17 Abstract ( )   PDF (999KB) ( )   In view of the application of cold regeneration technology of foamed asphalt in the common trunk highway in western Chongqing，the synthetic gradation curve of foamed asphalt was obtained based on the gradation of the original pavement material, the index of the aggregates, the expansion rate and half-life period of the foamed asphalt analyzed by the indoor test. The domestic cold regeneration equipment of foamed asphalt XCL300R was used for mixing. The effect of mixing frequency, mixing time, foamed asphalt content and cement content on the performance of cold regeneration asphalt foams were analyzed by indoor dry wet splitting test and freeze-thaw splitting test. Then the optimum mixing operation parameters of foamed asphalt mixture were determined. Combined with the actual construction situation on site, it is found that the quality of foamed asphalt mixture in this project and its various road performance indicators meet the specification requirements. References | Related Articles | Metrics

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Influencing Factors of Technical Interface Conflict in Railway Construction in Difficult and Dangerous Mountainous Areas WANG Lin,LIU Jia, BAO Xueying, HONG Yanyan 2022, 41(10): 130-137.  DOI: 10.3969/j.issn.1674-0696.2022.10.18 Abstract ( )   PDF (934KB) ( )   In order to prevent and control the conflict of technical interface of railway construction in difficult and dangerous mountainous areas, the WSR-K-Means++ model was proposed to identify the influencing factors of technical interface conflicts of difficult and dangerous mountain railways construction and classify them. Based on the methodology of the WSR system, the influencing factors of technical interface conflicts in difficult and dangerous mountainous railways construction were identified; the four-dimensional attribute membership degree of each influencing factor was defined and calculated from the perspective of four-dimensional attributes such as technology, responsibility, time and space. And Matlab was used to simulate the K-Means++ algorithm to cluster the membership. Taking a railway bid section in a difficult and dangerous mountainous area in southwest China as an example, the rationality and practicability of the WSR-K-Means++ model was verified. The results show that 80 factors affecting construction technology interface conflicts are identified, and the influencing factors should be divided into 4 levels. Through hierarchical management of influencing factors, it has certain practical value and reference significance for the timely prevention and control of technical interface conflicts in difficult mountain railways construction and the improvement of management efficiency. References | Related Articles | Metrics

Transportation Equipment

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Contact Analysis between High-Speed Train Wheel and Movable Point Frog of High-Speed Turnout ZHANG Jun, TIAN Zhipeng, NIU Yan, MA He, ZOU Xiaochun 2022, 41(10): 138-144.  DOI: 10.3969/j.issn.1674-0696.2022.10.19 Abstract ( )   PDF (2407KB) ( )   In order to study the worn problem of movable point frog of high-speed turnout, by use of CRH5 EMU wheel and No. 18 movable point frog profile with 60 kg/m rail, a three-dimensional wheel rail contact model was established to calculate elastic-plastic contact state between standard XP55 wheel and worn wheel and movable point frog of high-speed turnout at different positions. The research results show that the wheel rail contact state is affected by the wear degree and contact position. Compared with standard wheels, the transition section of worn wheels is relatively longer. Compared with the contact between the worn rear wheel and the movable point frog, the matching between the standard wheel and nose rail is unreasonable, which is more likely to cause stress concentration. The maximum equivalent stress generated by the contact between the standard and the worn rear wheel and the movable point frog exceeds the yield limit of the nose rail material, and the nose rail will produce plastic deformation, which will cause the movable point frog worn. References | Related Articles | Metrics

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Relationship between Temperature Variation and Frequency Variation Characteristics of Anti-hunting Damper and Vehicle Dynamic Performance SHI Lei1, ZHANG Longhua1, WU Xingwen2, XU Chuanbo2, GUO Zhaotuan2 2022, 41(10): 145-151.  DOI: 10.3969/j.issn.1674-0696.2022.10.20 Abstract ( )   PDF (852KB) ( )   Two typical anti-hunting damper structures, namely, the valve plate controlled damping structure and the helical spring controlled damping structure, were selected for experimental study. And the relationship between the temperature variation characteristics of the damper and vehicle dynamic performance was simulated and analyzed. The research results show that with the increase of oil temperature, the energy, dynamic stiffness and dynamic damping absorbed by two kinds of structure dampers decrease. Compared with high temperature, low temperature has a greater influence on the temperature variation and frequency variation characteristics of the damper. With the increase of frequency, the dynamic damping increases first and then decreases, and the dynamic stiffness increases first and then gradually remains unchanged. Moreover, the oil temperature has a greater impact on vehicle stability than on safety, and low temperature has a greater impact on dynamic performance than high temperature does. References | Related Articles | Metrics

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Analysis and Optimization of the Dynamic Performance of Outboard Guided APM Vehicles DU Zixue, TUO Hongming, YANG Zhen 2022, 41(10): 152-158.  DOI: 10.3969/j.issn.1674-0696.2022.10.21 Abstract ( )   PDF (1036KB) ( )   The outboard guided APM vehicles with self-steering axle were optimized based on the analysis on the stress state of APM vehicles with two different steering modes when passing through the curve. The dynamic model was established according to the characteristics of vehicle structure, then the dynamic performance of APM vehicle and vehicle operation stability were optimized and analyzed. The analysis results show that the outboard guided APM vehicle has good curve trafficability, the tire force can meet the operation safety requirements, and the vehicle body side roll angle is 1.55°. The optimized vehicle has appropriate ride comfort, its ride comfort index increases with the increase of the speed, and the evaluation grade of lateral ride comfort is excellent. When the vehicle speed is less than 40km/h, the vertical stability evaluation grade is good. When the vehicle speed is 40-60km /h, the vertical stability evaluation grade is qualified; the side deflection force of running wheels is small, the guiding torque is moderate, and the wear performance is also good. References | Related Articles | Metrics