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21 December 2021, Volume 40 Issue 12 Previous 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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Influence of Safety Early Warning System on Driving Behavior in Dense Fog Area CHANG Xin1, LI Haijian2, RONG Jian2, ZHAO Xiaohua2, LIU Lianlian2 2021, 40(12): 1-6.  DOI: 10.3969/j.issn.1674-0696.2021.12.01 Abstract ( )   PDF (1819KB) ( )   In order to study the impact of safety early warning system on speed control behaviour and driving safety in dense fog area of expressway, the driving simulation environment under different safety early warning systems was established. Through the driving simulation experiment, the driving behavior data of 35 drivers were obtained. The studied section was divided into three parts (no fog area, fog area transition section and dense fog area), and the influence of different experimental conditions (no warning, road facilities warning, on-board warning, on-board warning & road facilities warning) on speed control behavior and driving safety were analyzed. The results show that: the drivers individual attributes (gender, age and driving experience) have no significant impact on the drivers speed control behavior before and after entering the fog area, while the fog area early warning system has a significant impact on the drivers speed control behavior before and after entering the fog area. Under the condition of on-board early warning, the driver is more prepared for speed control before entering the fog area, and the operation stability is better after entering the fog area. Early warning information can improve the longitudinal driving safety level before and after the fog area, and when the on-board early warning system is turned on, the longitudinal driving safety level is higher. References | Related Articles | Metrics

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Fatigue Driving Detection Based on Eye Movement and EEG Features XU Junli, WANG Ping, MU Zhendong 2021, 40(12): 7-11.  DOI: 10.3969/j.issn.1674-0696.2021.12.02 Abstract ( )   PDF (2008KB) ( )   Fatigue driving is the main cause of traffic accidents. EEG or eye movement features are commonly used to detect driving fatigue. Compared with eye movement features, EEG features have higher detection rate, but the stability is not as good as that of eye movement features. In order to obtain high and stable detection rate, the wavelet entropy function was firstly used to extract the EEG features from the EEG electrodes CP4, TP8, T5, P3, Pz, P4, T6, O1, Oz and O2. And then EEG features and eye saccade length were fused, and KNN algorithm was used to establish a fatigue detection model based on fusion features. Finally, the detection model based on fusion features was compared with the detection model based on EEG features. The results show that: the detection mean values of the two detection models are not much different. but the detection effect based on fusion features is more stable than that based on EEG features.However, in terms of detection stability, the model based on fusion features is more stable than the model based on EEG features References | Related Articles | Metrics

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Short-Term Flight Delay Risk Forecast Based on KNN LIU Jixin1, 2,YANG Guang1, 2 2021, 40(12): 12-18.  DOI: 10.3969/j.issn.1674-0696.2021.12.03 Abstract ( )   PDF (521KB) ( )   In view of the current situation that civil aviation delay is still very prominent, the duration and probability of short-term flight delay are regarded as a risk problem. Considering the impact of bad weather, the risk was evaluated and predicted by combining the follow-up change of flight with external operation environment with mining flight history data. The principal component analysis method was used to analyze and screen many factors, and determine the key influencing factors of delay as the sample attributes of classification prediction algorithm. The KNN algorithm was used to build a model, which combined historical flight operation data and weather data to predict the departure delay and risk value of single flight leaving the airport in a short time. The experiment results show that the principal component analysis method can accurately find the key factors when there is information overlap between the variables. On this basis, KNN algorithm is used to predict the flight delay risk, which can achieve good results and has practical significance. References | Related Articles | Metrics

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Improved MDnet Target Tracking Algorithm in Complex Traffic Scene WANG Xiaoping1, SHI Xinlan2 2021, 40(12): 19-26.  DOI: 10.3969/j.issn.1674-0696.2021.12.04 Abstract ( )   PDF (18682KB) ( )   In the complex road traffic scene, the moving target image area was blurred by the factors such as motor vehicle, non-motor vehicle and pedestrian target occlusion, target rotation transformation, scale transformation and target rapid movement; the loss or destruction of the moving target image feature information was caused by illumination mutation, background clutter and other interference factors in the video image sequence, which resulted in insufficient tracking accuracy. In view of the above problems, the temporal correlation of moving targets in the image sequence was researched and analyzed, and the MDnet algorithm was improved. Meanwhile, a moving target tracking algorithm was proposed, which collected the optical flow characteristic time information of the target in the pre-image and used the optical flow change information of the moving target in the optical flow field to determine the exploration space of the moving target, so as to predict the position of the target in the current frame. After acquiring the exploration space of the moving target, a small convolution kernel was used to extract the texture information of the exploration space in a small field of view. In the model training, an exploration space with a side length of (1+70%) r was used, and the long-term and short-term complementary update methods were used. Every 5 frames were updated actively, and 20 candidate frames were updated passively when the score was lower than the accuracy threshold of 0.65. Research results show that in typical target occlusion, target tracking interference and motion blur scenes in complex traffic roads, the moving target tracking accuracy of the improved MDnet is 95.93%, which is 2.01% higher than that of the MDnet, and the performance of model fitting speed and target tracking accuracy is better. The improved MDnet that uses trajectory prediction and of small convolution kernel can effectively improve the performance of target occlusion and target fast motion tracking in complex road traffic scenes. References | Related Articles | Metrics

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Optimization of Traffic Microcirculation Road Network Considering Intersection Delay ZHANG Lili, GAO Xueyi 2021, 40(12): 27-32.  DOI: 10.3969/j.issn.1674-0696.2021.12.05 Abstract ( )   PDF (1022KB) ( )   In order to solve the problem of traffic congestion of arterial roads and low utilization rate of branch roads, a two-layer optimization model of traffic microcirculation network considering intersection delay was established by using the traffic microcirculation theory and considering the impact of intersections on the total delay of the road network. Under the constraints of road saturation, traffic capacity and investment amount, the upper model determined the roads constituting the traffic microcirculation network, and determined the reconstruction degree of the selected roads, so as to maximize the average travel speed of the road network in the planning area. The lower-layer model established the function minimizing the total impedance of the road network to assign OD traffic on the premise of meeting the requirements of upper-layer model, through combining the intersection delay with the travel time of the road section. And a solving algorithm for the model was established by genetic algorithm. Finally, taking the road network in the NEW-MART area in Daqing city as the research object, and a case study was carried out. The research results show that the average saturation of the arterial road is reduced from 0.72 to 0.65 and the average saturation of the road network is reduced from 0.65 to 0.43 after optimizing the traffic microcirculation road network. The proposed method can maximize the operation benefits of the road network within the scope of the investment quota. References | Related Articles | Metrics

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Comparison of Prediction Models of Vehicle Speed at Urban Unsignalized Intersection Based on Neural Network MA Yingying, ZHANG Zihao, WU Jiabin 2021, 40(12): 33-41.  DOI: 10.3969/j.issn.1674-0696.2021.12.06 Abstract ( )   PDF (6096KB) ( )   Traffic conflicts and accidents were concentrated at intersections in the urban road, especially at unsignalized intersections. Vehicle speed was an important factor affecting intersection safety. In order to efficiently and accurately predict the speed of vehicles passing through intersections, a prediction model of vehicle speed at urban unsignalized intersection based on neural network was proposed. Firstly, the intersection of Jianshe Road and Jiansheer Avenue in Guangzhou was photographed by video, and the data of the photographed intersection was extracted and classified by using Tracker video recognition software. A total of 700 valid data were collected. Secondly, the significant factors influencing the average speed of vehicles passing through unsignalized intersection were determined by using the correction analysis, and they were used as the input of prediction model. Finally, BP neural network, GA-BP neural network, deep neural network and adaptive neuro-fuzzy inference system were used to test respectively, and four evaluation indexes were used to compare and analyze the prediction effect of the model. The prediction results show that these four models are able to fit the complex relationship between the average speed of vehicles passing through the intersection and its influencing factors. Among them, the prediction accuracy of DNN, BPNN and ANFIS is 94.44%, 89.08% and 84.42% respectively, and the prediction accuracy of BP neural network improved by genetic algorithm (GA) was improved by 1.55% on the training set and 2.17% on the test set. References | Related Articles | Metrics

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Vehicle Mandatory Lane-Changing Duration during Highway Reconstruction and Expansion Period CHEN Jinsheng1, ZHANG Yanning2, MENG Lingxiao1, ZHANG Liming3 2021, 40(12): 42-46.  DOI: 10.3969/j.issn.1674-0696.2021.12.07 Abstract ( )   PDF (696KB) ( )   During the highway reconstruction and expansion period, the measures of closing part of traffic lanes and operating-while-construction would cause mandatory lane change before entering the construction section, which was easy to cause traffic accidents such as rear end collision and lateral collision. In order to analyze the mandatory lane change behavior of vehicles before entering the construction section, a driving simulation experiment was designed and the time and space data of lane change feature points were collected. According to the characteristics of the data, a survival analysis method based on Log-rank statistical test and Cox risk ratio model was proposed, and the mandatory lane-changing duration was analyzed. The results show that when the construction section is located in the right turn circular curve, the drivers mandatory lane change behavior occurs closer to construction section. Under the three road alignment conditions, the driver completes the lane change behavior only after entering the upstream transition section. Log-rank test results show that the duration of mandatory lane-changing behavior under the alignment conditions of different construction sections is significantly different, and the survival curve estimation results provide 75% quantiles of the duration of mandatory lane-changing behavior under different conditions. Cox model results show that the lane-changing duration is shorter when the construction section is located in the right turn circular curve. When the construction section is located in the right turn circular curve, the instantaneous probability of the end of mandatory lane change is 75.49% higher than that of straight-line section. References | Related Articles | Metrics

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Setting of Warning Signs for Animal Crossing on Expressway in High Altitude Area HAN Wanli1, LYU Yunfei2, ZHAO Jianyou2 2021, 40(12): 47-53.  DOI: 10.3969/j.issn.1674-0696.2021.12.08 Abstract ( )   PDF (2782KB) ( )   In order to reasonably design and effectively set up warning signs for animal crossing on highways in high altitude areas, starting with the characteristics of drivers, the driving sample line method was used to carry out field investigation and real vehicle test on Gongyu Expressway in Qinghai Province. First of all, by means of consulting experts, visiting local people and the assistance of traffic management departments, the situation of animal crossing in pastoral areas and nature reserves along the highway was investigated and analyzed; moreover, the evidence was obtained. Secondly, under the natural driving conditions, the driving speed and subjective feelings of drivers at different altitudes were collected synchronously on the vehicle equipped with GPS and two sets of high-definition tachographs. Finally, the animal crossing warning signs were designed, and the minimum requirements for sign setting were proposed. Based on the characteristics of drivers in high altitude areas, deceleration operation curve and visual recognition distance model, the pre-distance model of animal crossing warning signs was constructed. The research results suggest that in front of the nature reserve, the pattern of warning signs should be Tibetan antelope with the trend of movement, and the warning signs in front of pastoral areas and grazing channels should be matched with the pattern of Yak with yellow background and black pattern. Through the construction of the pre-distance model, the reference table of the leading distance of the warning signs for animal crossing the expressway in high altitude area based on the driver characteristics is obtained. References | Related Articles | Metrics

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Dynamic Stowage Optimization of Vehicles and Cargos in Road Freight Yard ZHANG He, WANG Yu, LIU Yu, XING Jianghao 2021, 40(12): 54-61.  DOI: 10.3969/j.issn.1674-0696.2021.12.09 Abstract ( )   PDF (815KB) ( )   Under the condition that the vehicles carried out the transportation task in batches in the road freight yard, the dynamic stowage of vehicles and cargos in each period was studied, and the vehicle turnover travel time prediction was also added. Considering the return of each batch of turnover vehicles and vehicle maintenance, taking the minimum number of vehicles required to complete the transportation task as the objective function, the dynamic stowage model of vehicles and cargos was established. Taking the transportation task of a freight station as an example, the solution multiplier method was used to solve the problem and compared with the corresponding static stowage case. The results show that the proposed model can optimize the allocation of vehicle resources and improve the economic benefit and operation efficiency of road freight yard. References | Related Articles | Metrics

Transportation Infrastructure Engineering

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Residents Route Choice Behavior Based on TPI Data SUN Qiuxia, ZHANG Yu, ZHAO Shulan 2021, 40(12): 62-68.  DOI: 10.3969/j.issn.1674-0696.2021.12.10 Abstract ( )   PDF (3219KB) ( )   Considering the travelers unknown travel environment risk, based on the prospect theory, the characteristics of travel preferences were introduced to construct the route choice model. Based on the measured data, the travel time reference point was set by considering the travel time and the waiting time of traffic lights, etc., and the value function and decision weight function were derived. The change relationship diagram between the prospect value of the alternative path and the reference point was made, and the questionnaire data was compared with the results of the model. The research results show that: the prospect theory can effectively describe the route choice behavior of the traveler. The size of the reference point has an important influence on the route choice of the traveler. The larger the reference point, the closer the prospect values of the two alternative routes. Therefore, the traffic management decision-maker should optimize the network structure between OD according to the attribute characteristics of the route, so as to achieve the balance of the traffic flow state between OD. References | Related Articles | Metrics

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Atmospheric Environment Efficiency Evaluation and Spatial Difference Analysis on the Yangtze River Economic Belt ZHANG Yu1, MAO Yanying2, JIAO Liudan1, WU Ya3 2021, 40(12): 69-76.  DOI: 10.3969/j.issn.1674-0696.2021.12.11 Abstract ( )   PDF (5449KB) ( )   Based on the background of urban ecological priority and green and high-quality development in the Yangtze River Economic Belt, an atmospheric environmental efficiency measurement model including three main air pollutants such as SO2, smoke (dust) and PM2.5 was constructed on the basis of the panel data of 80 cities in the Yangtze River economic belt from 2005 to 2017, by considering the combination of the Super-SBM model of unexpected output and Malmquist productivity index. And its spatial differences and dynamic evolution characteristics were analyzed. The research results show that the overall atmospheric environmental efficiency of the Yangtze River Economic Belt is low, with an average value of 0.59; the efficiency of Shanghai, Suzhou, Jinhua and Wuxi in the lower reaches is significantly better than that of other cities, while the atmospheric environmental efficiency of middle and upper reaches cities such as Huainan, Guangyuan and Huangshi is poor. From the spatial distribution of atmospheric environmental efficiency, most of the cities with effective atmospheric environmental efficiency are concentrated in the lower reaches of the Yangtze River, and there is more room for improvement in the cities in the middle and upper reaches, especially in the urban agglomeration of Western Hunan, central Hubei and Chengdu-Chongqing. From the dynamic evolution characteristics of atmospheric environmental efficiency, the overall level of atmospheric environmental efficiency has increased by 7.6% and 92.5% of cities have improved. According to the decomposition results of Malmquist productivity index, the technological progress and change plays a leading role in improving the efficiency of atmospheric environment. References | Related Articles | Metrics

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Application of UAV Airborne LiDAR and BIM Technology in Design of Complex Terrain Highway XIANG Shiyao, XU Run, YAO Shoufeng, ZHANG Tao, WANG Yitong 2021, 40(12): 77-81.  DOI: 10.3969/j.issn.1674-0696.2021.12.12 Abstract ( )   PDF (7847KB) ( )   According to the characteristics of highway design in complex terrain areas, the UAV airborne LiDAR and BIM technology were combined and applied to highway design, which could solve the problem of difficult acquisition of basic geographic data and verify the rationality of the design scheme and the matching degree with the environment through three-dimensional BIM design. The specific application shows that the proposed technical method has obvious advantages in highway design in complex terrain, and is helpful to improve the quality of survey and design. References | Related Articles | Metrics

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Bridge Model Design and Information Processing Based on BIM Technology JIANG Haopeng, JIANG Annan 2021, 40(12): 82-89.  DOI: 10.3969/j.issn.1674-0696.2021.12.13 Abstract ( )   PDF (3165KB) ( )   With the continuous updating of bridge design methods in China, the design methods dominated by BIM technology are also increasing, but the design modes are different. In order to make BIM bridge model design more simple, accurate and information processing more effective, the technical model of BIM bridge design and construction management based on IFC standards was improved firstly, which was based on the IFC standard as the theoretical basis and combined with the technical route of bridge design and construction management in China. Secondly, the bridge BIM model data coding rules were constructed according to the building information model classification standards. Finally, the modeling and deepening design of the project were successfully carried out through Revit software. The research results can provide theoretical support and technical experience for the development of BIM technology in bridge construction in China. References | Related Articles | Metrics

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Improved Method for Calculation of Datum Strand Adjustment of Suspension Bridge DENG Xiaokang, SUN Jie 2021, 40(12): 90-95.  DOI: 10.3969/j.issn.1674-0696.2021.12.14 Abstract ( )   PDF (624KB) ( )   Based on the analysis of the main cable shape of the suspension bridge and the relationship between the deformation and stress of the main cable, an improved method for calculation of datum strand adjustment of suspension bridge was proposed. Taylor formula was used to expand the alignment equation at the target empty cable state, and the relationship between the cable length adjustment the midsagittal height change of the main cable span can be obtained by solving the expanded equation. At the same time, the calculation accuracy of the methods using first-order and second-order Taylor expansion to fit the main cable shape equation was analyzed, and the application of the proposed method in the case of equal height main tower and unequal height main tower was studied. The results show that the improved method has higher accuracy. References | Related Articles | Metrics

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Effect of Microscopic Contact Friction of Aggregate/Asphalt System on Compaction Characteristics SU Jinfei, LI Peilong, ZHU Lei, DONG Chao 2021, 40(12): 96-102.  DOI: 10.3969/j.issn.1674-0696.2021.12.15 Abstract ( )   PDF (3649KB) ( )   To investigate the compaction characteristics of the asphalt mixture, the specimen was molded by Superpave Gyratory compactor, and the compaction curve average slope K1, K2 and compaction energy index CEI were used to characterize the compaction characteristics of asphalt mixture. Based on the self-developed mineral contact tester and interface contact slip tester, the maximum slip force and the maximum slip shear stress were proposed to respectively characterize the contact characteristics of the particle system and the asphalt mixture. The influence of contact friction effect of mineral aggregate / asphalt system on compaction characteristics was analyzed from the microscopic level. The test results show that the more the coarse aggregates, the stronger the contact effect among the particles, and the more difficult the asphalt mixture is to be compacted. AC-13 asphalt mixture has better workability than SMA-13 asphalt mixture and OGFC-13 asphalt mixture. The larger the nominal maximum particle size, the more energy required for the asphalt mixture to achieve the target compactness and the better the anti-slipping deformation ability. The more asphalt content or the higher compaction temperature will reduce the contact strength of asphalt mixture, so as to improve the workability. The maximum slip shear stress ratio is more suitable to evaluate the compaction characteristics of asphalt mixture than K2 after exposure to traffic. References | Related Articles | Metrics

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Compatibility Mechanism of Organic Bentonite Asphalt-Based Nanocomposites Based on Microstructure SUN Jishu1, TIAN Hongbin2 2021, 40(12): 103-109.  DOI: 10.3969/j.issn.1674-0696.2021.12.16 Abstract ( )   PDF (3305KB) ( )   According to the preparation method of melt intercalation composite, inorganic and organic bentonite pitch-based nanocomposites with different dosages were prepared respectively. Organic bentonite was selected through segregation test and routine index test, and the compatibility of organic bentonite and asphalt was characterized from the micro scale based on SEM, XRD and FTIR. Finally, its application properties were tested. The results show that organic bentonite can be uniformly dispersed in asphalt, and the organic bentonite with 4% content has the largest structural layer spacing in asphalt and has the strongest adsorption with asphalt, which can be used as the best content. The application performance indicates that the organic bentonite has a great improvement on the high temperature performance of the asphalt. But it has a negative impact on the low temperature performance, which provides a theoretical basis for further compounding other modifiers to make up for the single performance of the composite. References | Related Articles | Metrics

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Experimental Study on Full Time Domain Damage of Concrete Based on Acoustic Emission YANG Kang1, LI Dongxue2, HE Zhaoyi2, ZHOU Hanlin1, LI Jiaqi1 2021, 40(12): 110-116.  DOI: 10.3969/j.issn.1674-0696.2021.12.17 Abstract ( )   PDF (4944KB) ( )   In order to study the variation law of acoustic emission signals during the damage and failure process of cement concrete in the full time domain, the uniaxial compression tests were carried out on cement concrete specimens, and acoustic emission was used to collect damage signals in the whole process. By combining the load-displacement curve with AE signal parameters, the damage process of concrete specimens in the full time domain was divided into stages, and the variation characteristics of AE signal parameters in each stage of concrete load-bearing damage were analyzed. The variation law of b value in each stage of concrete damage was studied. Frequency factor H was introduced to analyze the frequency change of specimens during damage. The results show that the concrete damage process can be divided into four stages, and acoustic emission signal characteristics have obvious differences in each stage; b value can be used as an important means for concrete damage evaluation. When the damage stage is divided, it is more simple and intuitive compared with acoustic emission parameters. The sudden increase of the proportion of high frequency AE signals can be used as an important indicator of early warning and monitoring. References | Related Articles | Metrics

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Experimental Study on Shear Fracture Evolution Mechanism of Non-penetrating Serrated Structural Surface JI Feng1, YAN Xingtian2, ZHANG Bo1 2021, 40(12): 117-123.  DOI: 10.3969/j.issn.1674-0696.2021.12.18 Abstract ( )   PDF (2676KB) ( )   The rock mass was composed of rock and structural plane. The structure plane often played a decisive role in the deformation and failure of the rock plane mass. In the project, most of the rock masses encountered were non-penetrating structural plane rock masses. The failure mode and strength criterion of the non-penetrating structural plane rock masses had very far-reaching significance. Based on the control variable method and direct shear test, the artificially cast non-penetrating serrated structural surface specimens were used to study the deformation and failure characteristics and shear strength variation rule of non-penetrating serrated structural planes with different structural plane inclination angles under different axial pressures. The results show that with the increase of the preset structural plane inclination angle and normal compressive stress, the failure mechanism of non-penetrating serrated structural surface will gradually change from tension shear-dilatancy failure and tension shear-dilatancy shear failure to shear failure, and its shear strength will also increase. And a new empirical formula for shear strength is established accordingly. References | Related Articles | Metrics

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Performance Reliability of Braking System Based on Super Ellipsoid Bayesian Network QI Jinping1,2,3, ZHOU Yahui1, LI Shaoxiong1, WANG Kang1 2021, 40(12): 124-129.  DOI: 10.3969/j.issn.1674-0696.2021.12.19 Abstract ( )   PDF (847KB) ( )   The braking system had the characteristics of diverse working conditions, functional levels and complex operation relationship between internal structures, and was often affected by wear, vibration, fatigue, impact, over-maintenance and other factors, which caused the problems of multiple fault states and multiple failure modes between normal operation and complete failure of the system and components in the actual operation process. Through the reliability analysis method based on the super ellipsoid Bayesian network, the multi-state problem of the Bayesian network describing the fault states of components and events was studied. Meanwhile, combing with the super ellipsoid Bayesian network model to constrain the interval variables, the super ellipsoid Bayesian network model was constructed, which was introduced into the reliability analysis of motor car breaking, and compared with the analysis results of interval Bayesian network. The results show that compared with the interval Bayesian network, the analysis results of the super ellipsoid Bayesian network model have smaller probability interval range and higher accuracy, which not only solves the conservative problem of interval calculation results of interval Bayesian network, but also improves the accuracy of reliability analysis of braking system. Then, by solving the important parameters such as sensitivity and posteriori probability of the braking system, the weak links of the proposed system and the high-risk events affecting the reliability of the braking system are found out, which provides theoretical guidance for the formulation of the maintenance strategy and technical transformation. References | Related Articles | Metrics

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Test, Modeling and Parameter Identification of Seated Human Body Exposed to Lateral Vibration LUO Shuang1, SHU Hongyu2 2021, 40(12): 130-135.  DOI: 10.3969/j.issn.1674-0696.2021.12.20 Abstract ( )   PDF (1897KB) ( )   Lateral vibration of seated human bodies belongs to the category of whole-body vibration, which affects ride comfort. Aiming at the problem of insufficient research on the lateral vibration characteristics of seated human bodies under low-frequency and large-amplitude excitation, through the combination of vibration experiment and mechanical model, the lateral vibration experiment, modeling and parameter identification of the seated human bodies were studied. A crank-slider vibration test bench was developed. Lateral vibration experiments under single-frequency excitation from 0.5 to 8.0 Hz were carried out on 10 young volunteers with the ages of 21~28. Micro attitude reference systems were used to measure the lateral accelerations of the seat pedal, the upper and lower body of the seated human bodies, and the transmission characteristic data from the seat pedal to the upper and lower body were obtained. Considering the seated human body as two rigid bodies, a biomechanical model with two degree-of-freedoms expressing the lateral vibration of the seated human body was established, and the expression of transmission characteristics was deduced. Taking the sum of squares of relative errors as the objective function, the test data were fitted by genetic algorithm, the model stiffness and damping parameters were identified, and the fitting degree was introduced to evaluate the fitting effect of the proposed model. Research results show that the lateral main resonance frequency of the volunteers upper body is 2.4~3.1 Hz and that of the lower body is 2.4~3.2 Hz; moreover, the upper body has obvious second-order resonance over 5 Hz. The amplitude of upper body transmissivity is 1.45 ~ 1.89, and that of lower body is 1.53~2.38. The resonance frequency of the lower body is slightly higher than that of the upper body, and the vibration is more intense. The proposed biomechanical model with two degree-of-freedoms can accurately describe the lateral vibration characteristics of the seated human body. References | Related Articles | Metrics

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Multi-parameter Optimization of Suspension System of Straddle Monorail Vehicle Based on Taguchi Robust Design ZHAO Shuen, NIE Xiaorui, CHEN Wenbin 2021, 40(12): 136-142.  DOI: 10.3969/j.issn.1674-0696.2021.12.21 Abstract ( )   PDF (2392KB) ( )   In order to further improve the running stability of straddle-type monorail vehicles, Universal Mechanism software was used to establish a monorail vehicle-rail vehicle dynamics model. Taguchi experiment and robust optimization design methods were used to optimize the design of the key parameters of the suspension system of monorail vehicles. The key suspension parameters were screened out by the variation coefficient method, and the influence of controllable design parameters and random interference factors on the running stability of monorail vehicles was comprehensively considered. The key suspension parameters were subjected to orthogonal experiments. And the signal-to-noise ratio analysis was performed on the test results to determine the optimized parameters. The simulation verification of the optimized suspension parameters shows that the vertical and horizontal stability indexes of monorail vehicles are improved, and the robustness of the suspension system is improved. The proposed method is effective for optimizing the suspension system parameters. References | Related Articles | Metrics