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16 April 2021, Volume 40 Issue 04 Previous Issue    Next Issue
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Transport+Big Data and Artificial Intelligence
Transportation Infrastructure Engineering
Transportation Equipment


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Transport+Big Data and Artificial Intelligence

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Pilots Attention Allocation Behavior in Single-Engine Failure Scenario JIN Huibin1, HU Zhanyao2, YU Guihua2 2021, 40(04): 1-5.  DOI: 10.3969/j.issn.1674-0696.2021.04.01 Abstract ( )   PDF (3569KB) ( )   In order to explore the attention distribution rules of the pilots before and after the single-engine failure, and to provide reference for flight training, the diamond 42 simulator and the head-mounted eye-tracker were used to build an experimental platform. 18 flight instructors and 18 students were selected to take part in the single-engine failure experiments. Flight parameters and eye movement data of the subjects were collected during the experiments. The response time, the fault processing time and the maximum heading change were used as performance metrics to determine whether a subject belonging to performance excellent group or poor group. Then, the gaze frequency of the two groups of subjects at each area of interest (AOI) of the main flight display was compared and analyzed before and after the single-engine failure. The results show that the subjects of group with poor performance pay too much attention to the attitude and heading of the aircraft after a single-engine failure, but fail to pay enough attention to the key engine indication system and the control interface, so their emergency handling is unskilled; while those of group with better performance can maintain reasonable allocation of attention resources to each instrument area and can increase the frequency of fixation to the AOIs at the same time, which plays a key role in the single-engine failure recovery. References | Related Articles | Metrics

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Optimization of the LNG Import Maritime Transport Network in China by Considering Coastal Transshipment LYU Jing, WANG Qinqin, SHENG Huimin 2021, 40(04): 6-12.  DOI: 10.3969/j.issn.1674-0696.2021.04.02 Abstract ( )   PDF (838KB) ( )   Based on the current situation that China’s import LNG carriers were mainly long-term charterers, and considering the addition of coastal two-way transshipment in the import LNG shipping network at the same time, a mixed integer linear programming model with the objective of minimizing the total cost of marine transportation was established to optimize Chinas import LNG shipping network. At the same time, the economy of using small and medium-sized LNG carriers in Chinas coastal two-way transshipment network was analyzed, the appropriate hub port under the economic situation of coastal two-way transshipment was found out and the fleet configuration required for coastal two-way transportation was obtained. From the results of the optimization, it is found that for some small and medium-sized LNG terminals with limited ship types in Chinas coastal areas, the coastal two-way transshipment mode can be adopted to meet their needs, which can effectively reduce the shipping cost of Chinas imported LNG. References | Related Articles | Metrics

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Optimization of Cycle Length of Intersection Signal Based on RBF Neural Network Prediction CHENG Wei1, LIU Xiang1, LEI Jianming2 2021, 40(04): 13-18.  DOI: 10.3969/j.issn.1674-0696.2021.04.03 Abstract ( )   PDF (660KB) ( )   Aiming at the situation that the existing intersection signal timing only depended on a single historical data, an optimization method of intersection signal cycle length based on RBF neural network prediction was proposed in order to make full use of the historical data, according to the two characteristics of urban traffic flow, such as periodicity and uncertainty. Firstly, the RBF neural network was trained according to the historical traffic flow of the intersection in the evening peak, and the trained RBF neural network was used to predict the traffic flow of the intersection in the evening peak of the next day; then the predicted traffic flow was converted into the equivalent straight traffic flow by combining with the straight equivalent coefficient method; and then a multi-objective optimization model with average vehicle delay and average vehicle parking rate as the main control objectives was established, and a genetic algorithm was established in MATLAB to solve the problem. Finally, the results obtained by the proposed method were compared with those obtained by the Webster method and the measured traffic flow in actual time allocation with the average vehicle delay and vehicle parking rate as the evaluation index. The results show that: compared with Webster method and actual time allocation, the proposed method can reduce the average vehicle delay by 12% and 2% on weekdays, and 20% and 18% on non-weekdays, which effectively improves the traffic efficiency of intersections. References | Related Articles | Metrics

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Information View and Particle Swarm Optimization Algorithm in Urban Traffic Congestion SHI Tianliang, WANG Wenguang 2021, 40(04): 19-25.  DOI: 10.3969/j.issn.1674-0696.2021.04.04 Abstract ( )   PDF (710KB) ( )   Traffic congestion is an “urban disease” in China in recent years. It is urgent to find out the key factors of traffic congestion. Firstly, the key factors affecting traffic congestion were summarized. And then, the reduction algorithm combined with information view theory and particle swarm optimization algorithm was used to select the characteristics of key factors, and the key factors affecting traffic congestion were screened out. The simulation test results show that the proposed algorithm is effective and accurate, which provides an effective solution strategy for solving the problem of urban traffic congestion. References | Related Articles | Metrics

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Risk of Vehicle Lane Change Behavior on Highway HE Yulong1, 2, LIU Lei1,2, CHI Jiaxin1,2 2021, 40(04): 26-33.  DOI: 10.3969/j.issn.1674-0696.2021.04.05 Abstract ( )   PDF (1118KB) ( )   As one of the basic driving behaviors of vehicles, lane change has a vital impact on the road safety. Aiming at the current situation of frequent accidents caused by lane change behavior on highway, the characteristics of lane change vehicles and their adjacent vehicles in the process of lane-changing and the relationship between position and speed were analyzed to construct the safe lane change model. The research results show that through MATLAB simulation of lane changing behavior with different lane changing characteristics, the dynamic safety distance between vehicles with different speed, acceleration and driver reaction time can be determined, so that the dynamic critical threshold of lane change safety and risk is determined. The research provides theoretical support for the lane change early warning system of automatic driving. References | Related Articles | Metrics

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Critical Speed of Vehicles Running Stably on Expressway in the Weather of Rain and Snow under Strong Wind WANG Lu1, CHEN Xiaoxin2, LI Huaen1 2021, 40(04): 34-40.  DOI: 10.3969/j.issn.1674-0696.2021.04.06 Abstract ( )   PDF (2328KB) ( )   In order to ensure the driving safety of vehicles under the weather conditions of strong wind, rain and snow, the vehicle model, the meteorological environment model and the road model were constructed, and the simulation analysis was carried out by using the CarSim software. Considering the situation of vehicles on the rainy water road, snowy road and snowy iced road under different wind levels, the critical speed of vehicle running stably was studied by taking the specific linear combination as an example and selecting the lateral force coefficient and the lateral offset as the evaluation index. The speed limit suggestions of vehicles on straight line and circular curve under different weather conditions were given. The results show that when the road section alignment is straight, the vehicle speed should not be higher than 80 km/h when the vehicle is on the waterlogged road in rainy days with grade 5 wind or above; when the road section is circular, the vehicle speed should be controlled below 50 km/h. When vehicles are on snowy or icy road with grade 5 wind or above, the safety speed limit value is 60 km/h when the road section alignment is straight; when the road section is circular curve, the speed should be controlled below 30 km/h. The research results can provide some reference for safe driving and road speed limit in severe weather, and provide the calculation method of critical speed of vehicle safely driving under the action of wind, rain and snow. References | Related Articles | Metrics

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Optimization of the Departure Interval of Urban Rail Train Considering Operational Income and Passenger Compartment Space Perception ZHU Shunying1, LIU Bin1, LIU Bin2, YANG Youzhen3, WANG Hong1 2021, 40(04): 41-47.  DOI: 10.3969/j.issn.1674-0696.2021.04.07 Abstract ( )   PDF (771KB) ( )   The operation income and the passenger compartment space perception of the rail transit system is an opposite relationship. Through the study of these two factors to optimize the departure interval of rail transit, the passenger compartment space perception could be improved within a reasonable income range. Considering the influence of the train’s upstream and downstream direction and the constraint of factors such as passenger waiting time, supply and demand balance, maximum passenger capacity, number of vehicles equipped and the safety interval of train operation, the departure interval optimization model was established, and the genetic algorithm was used to solve the multi-variable nonlinear optimization problem. The optimization schemes of different sub-periods were obtained. The proposed method was applied to optimize and calculate Wuhan Rail Transit Line 4 during different periods of peak hours. It is found that after the adjustment of the transit departure interval, the small decrease of operation income can effectively improve the passenger compartment space perception. Through passenger flow sensitivity analysis, the change law of rail operation income and passenger compartment space perception under the condition of passenger flow increasing to a certain extent is studied, which can provide reference for the decision-making of urban rail train operation. References | Related Articles | Metrics

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Node Labeling Algorithm of Shortest Path Considering Turn Delay LUO Ying, HE Qiang 2021, 40(04): 48-53.  DOI: 10.3969/j.issn.1674-0696.2021.04.08 Abstract ( )   PDF (666KB) ( )   It is difficult to reflect the real traffic situation when the shortest path algorithm is applied without considering the turn delay in urban road network, because that travel delays at the intersection of urban road network may be larger than the driving time on road section. The existing shortest path algorithm considering turn delay was analyzed. The extension network method lacked practicability due to the excessive time and space overhead. The other algorithms, including dual network method, node labeling algorithm and arc labeling algorithm, were essentially to solve the shortest path problem including node weight and edge weight, and the final solution was node labeling algorithm. The typical node labeling algorithm — Dijkstra algorithm was improved. The steering discrimination was completed by recording the nodes previous node, the time complexity of the proposed algorithm was optimized from O(n2) to O(nlogn) by smallest heap optimization and the data structure of the proposed algorithm was given. The program coding was completed, and the proposed algorithm was validated through an example. The results show that the shortest path of the urban road network will change after considering turn penalties, meanwhile, the time complexity of the algorithm will decrease after heap optimization. References | Related Articles | Metrics

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Multimodal Transportation Route Selection of Fresh Products Considering Time Window with the Participation of High-Speed Rail LI Yumin, QIU Meng, YAN Kaili, LIU Qixin 2021, 40(04): 54-61.  DOI: 10.3969/j.issn.1674-0696.2021.04.09 Abstract ( )   PDF (1214KB) ( )   According to fresh products transportation demand of small freight volume and high time efficiency, high-speed rail was proposed as a transportation mode to participate in the multimodal transport of fresh products. Considering the mixed time windows at intermediate nodes and the constraint of soft time window of destination receiving, the combined model of multimodal transportation route selection and transportation mode was constructed, whose objective was to minimize the total cost of transportation cost, transfer cost, time penalty cost, cold storage cost and quality loss cost. Taking Harbin-Kunming multimodal transportation path as an example, the hybrid Taguchi genetic algorithm was used to solve. The results show that it is better to choose the transportation combination method of “high-speed rail+highway” when the time window at intermediate nodes is considered. In addition, the existence of the node time window will increase time value cost to a certain extent, but it has strong practical rationality, which indicates that the proposed model can effectively provide practical path reference for the rapid multimodal transportation of fresh products. References | Related Articles | Metrics

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Expressway Customer Business Value Mining Based on RFMS WENG Xiaoxiong, XIE Zhipeng 2021, 40(04): 62-69.  DOI: 10.3969/j.issn.1674-0696.2021.04.10 Abstract ( )   PDF (803KB) ( )   With the occurrence of highway congestion and uneven spatial and temporal distribution of traffic flow in China, the supply side reform of expressway, which took expressway differential charging as the main way, was an important measure for the diversified expressway users to alleviate the current highway congestion. Based on the customer segmentation theory, the RFMS model was put forward, in which the expressway users were divided into heterogeneous customer groups and their commercial value was analyzed. Considering the structural characteristics of expressway toll data, the small clustering phenomenon of traditional k-means algorithm in the initial cluster center selection and big data clustering was improved, a hybrid algorithm combining Adaboost and k-means + + was established, and a comparative analysis of the clustering effect was carried out. The research results show that the Adaboost-k-means + + hybrid algorithm can improve the clustering effect; the business value mining method of expressway customers based on RFMS can effectively divide heterogeneous customer groups and evaluate customer value, which can provide reliable theoretical support for expressway differential charging and expressway operation management departments. References | Related Articles | Metrics

Transportation Infrastructure Engineering

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Correlation Function Method for Parameter Identification Based on Random Excitation Response FU Lilei 2021, 40(04): 70-75.  DOI: 10.3969/j.issn.1674-0696.2021.04.11 Abstract ( )   PDF (484KB) ( )   Based on the wind tunnel test of bridge sectional model, the differential equations of vertical and torsional coupling vibration of bridge segment model were established. The effect of wind load on bridge could be considered as aero-elastic damping force, aero-elastic stiffness and Gaussian random excitation force. By use of the theory of random vibration, the correlation function equation of two-degree-of-freedom vibration response under random excitation was derived, and the parameter identification equation was constructed by the least square method. The correlation function method for parameter identification based on random excitation response was proposed, and the validity of the proposed method was verified by numerical simulation. Finally, the proposed method was applied to identify the stiffness matrix and damping matrix in wind tunnel test system. The research shows that the results obtained by the proposed method are close to those obtained by the free vibration time domain identification method under low wind speed conditions. References | Related Articles | Metrics

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Model Test and Numerical Simulation Research on Reasonable Structure of Steel-Concrete Composite Section in Space Rigid Frame SU Xiaobo1, XIAO Lin2 2021, 40(04): 76-82.  DOI: 10.3969/j.issn.1674-0696.2021.04.12 Abstract ( )   PDF (6015KB) ( )   Based on a steel-concrete composite section in space rigid frame structure, a static load test of 1∶2 large-scale segment model was completed according to the principle of “stress equivalence”. Meanwhile, a precise finite element model considering contact nonlinearity and shear stiffness was established. On the basis of good coincidence between theoretical calculation and model test, the influence of different shear stiffness and structural details of PBL shear key on the mechanical characteristics of the joint section was discussed. The research results show that in the original design structure, the shear stiffness has limited influence on the calculation results, and the setting of bearing plate has significant influence on the magnitude and distribution rule of stress. The combination of bearing plate and shear key can achieve ideal comprehensive effect. References | Related Articles | Metrics

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Opening Length of the Same Median Strip of Highway Interchange Exit with Separation of Passenger and Truck PAN Binghong1, 2, REN Hui2, SHAN Huimin1, HUO Yongfu1 2021, 40(04): 83-90.  DOI: 10.3969/j.issn.1674-0696.2021.04.13 Abstract ( )   PDF (968KB) ( )   Through analyzing the driving state of the vehicle in the opening length of the same median strip of highway interchange exit with separation of passenger and truck, the constant velocity offset sinusoidal lane changing model was proposed. The open section of the same median strip was divided into the front transition section, the waiting segment and the back transition segment; and a calculation model for the same median strip of highway interchange exit with separation of passenger and truck was established to meet the requirements of drivers driving safety and comfort. By analyzing the relevant parameters of the proposed model, the recommended minimum values for the median strip opening length under different super-elevation and different design speed were proposed. The VISSIM simulation model was established by taking the traffic conflict rate as the safety evaluation index. Based on the traffic conflict evaluation model (SSAM), the recommended values of the opening length of the same median strip were simulated and verified. The results show that according to the fuzzy membership evaluation of conflict rate, when the opening length is greater than or equal to the recommended value, the road level is safe or safer. The model calculation is reasonable, and the recommended value of the opening length of the same median strip calculated by the proposed model is feasible. References | Related Articles | Metrics

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Numerical Simulation Study on Fatigue Crack Propagation of Composite Pavement KONG Lingyun1, ZOU Shengnan1, HUANG Linhuo2, WU Haiying3, YU Miao1, YANG Bo1 2021, 40(04): 91-97.  DOI: 10.3969/j.issn.1674-0696.2021.04.14 Abstract ( )   PDF (2191KB) ( )   Based on the virtual crack closure method (VCCT) and the generalized Paris formula, the fatigue crack propagation life of tunnel composite pavement was studied. Firstly, the existing virtual crack closure method was improved and a subroutine UEL that could simulate the fatigue crack propagation of composite pavement was developed. Using the finite element software Abaqus, the subroutine UEL was called to calculate the energy release rate and stress intensity factor of the pavement structure, and the fatigue crack propagation life was obtained by combining with the generalized Paris formula. The improved virtual crack closure method could calculate the energy release rate corresponding to various crack lengths in one model, which greatly reduced the computational cost. The numerical simulation results show that the type I stress intensity factor KⅠ increases with the crack propagation length. With the increase of the crack length, type II stress intensity factor KⅡ first decreases, then increases. The effective stress intensity factor Keff and the type II stress intensity factor KⅡ change roughly the same. By use of the improved virtual crack closure method, the effects of upper and lower layer modulus, concrete layer modulus and overload on fatigue crack propagation life were studied. The results show that the increase of the overload coefficient will significantly reduce the fatigue crack propagation life of the composite pavement; the fatigue crack propagation life will increase with the increase of the upper and lower layer modulus, which is approximately linear with the upper and lower layer modulus. The fatigue crack propagation life will also increase as the modulus of the concrete layer increases, but the increase rate will gradually slow down. The order of influence on the fatigue life of the road surface is: the overload coefficient > the concrete modulus > the underlying layer modulus > the upper layer modulus. The research results have certain reference value for the structural design of composite pavement. References | Related Articles | Metrics

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Properties of Biodiesel-Plastic Cracking Wax Composite Warm Mix Modified Asphalt LING Tianqing1, WEI Qiao2, LI Chuanqiang3, YUAN Hai2, YANG Qingchen3 2021, 40(04): 98-104.  DOI: 10.3969/j.issn.1674-0696.2021.04.15 Abstract ( )   PDF (2326KB) ( )   In order to reduce the energy combustion and gas pollution of hot mix asphalt mixture and solve the problem of the high cost of warm mix agent in China, the biodiesel-plastic cracking wax (oil-wax for short) compound warm additive agent was independently developed. The physic-chemical characteristics of oil-wax warm mix agent were characterized by Fourier transform infrared spectroscopy (FTIR) and thermogravimetric test (TG).The viscosity reduction effect, high temperature performance, low temperature performance and anti-aging performance of oil-wax compound modified asphalt, whose content of oil-wax warm additive agent were 5%, 6%, 7% repetitively, were evaluated by rotational viscometer (RV) test, rotating thin film oven (RTFO) test, dynamic shear rheometer (DSR) test and bending beam rheometer test (BBR), and were compared with Sasobit modified asphalt and Evotherm modified asphalt. Based on the surface energy theory, the surface energy parameters of oil-wax compound modified asphalt, Sasobit modified asphalt and Evotherm modified asphalt were measured by contact angle test. The adhesion work of three kinds of warm mix modified asphalt and two kinds of aggregate was calculated respectively. The results show that the modification process of oil-wax warm mix agent for asphalt is mainly physical action, and oil-wax warm mix agent has better thermal stability. The viscosity of the oil-wax compound modified asphalt with 6% oil-wax warm additive agent is about 63% lower than that of 70# asphalt whose temperature reduction effect is similar to that of 3% Sasobit modified asphalt mixture. The mixing temperature of oil-wax modified asphalt mixture is about 30 ℃ lower than that of hot mix asphalt mixture. Oil-wax warm additive agent can improve the anti-aging performance and high temperature performance, but go against the low temperature performance. According to the comprehensive analysis, the recommended content of oil-wax warm additive agent is 6%. Compared with 3% Sasobit modified asphalt, 6% oil-wax modified asphalt has better low temperature performance and adhesion, while its high temperature performance is slightly worse. And 6% oil-wax modified asphalt has better high temperature performance and adhesion while its low-temperature performance is worse, compared with 0.6% Evotherm modified asphalt. References | Related Articles | Metrics

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Influence Factors of Shield Tunneling Efficiency in Granite Strata ZHANG Shihao1, LI Tong2,3,4, LI Xuan5, HAO Baoan1, SHI Chun1 2021, 40(04): 105-111.  DOI: 10.3969/j.issn.1674-0696.2021.04.16 Abstract ( )   PDF (4659KB) ( )   In order to compare the tunneling efficiency of shield in granite quantitatively, a characteristic parameter characterizing the tunneling efficiency was proposed. Based on the field test of tunneling and in-situ measurement of strata parameters in the first phase project of Shenzhen Urban Rail Transit Line 8, the correlation between the influencing factors and the tunneling efficiency was analyzed. The control measures for the tunneling efficiency of different strata were proposed. The research results show that both the rock uniaxial compressive strength and rock mass integrity coefficients are negatively correlated with the tunneling efficiency; the empirical relationship between strata parameters and tunneling efficiency can be expressed approximately by the power function. The inverse proportional function can be used express to approximately the empirical relationship between the tunneling efficiency and the total thrust; the influence of the total thrust on the tunneling efficiency decreases with the increase of the rock hardness. The combination of tunneling parameters with lower thrust and higher rotation speed is more efficient in the lightly weathered strata. In the moderately weathered strata, higher tunneling efficiency can be achieved by setting the total thrust and the cutter disc rotation speed to 14 000±1 000 kN and 1.6±0.1 rpm, and the tunneling speed can be improved on such basis in a short time by sacrificing the tunneling efficiency simultaneously. References | Related Articles | Metrics

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Experimental Study on Expansion Force of Expansive Remolded Mudstone WANG Qingzhou1, SUN Chao1, TAN Aolong2, WEI Lianyu1 2021, 40(04): 112-117.  DOI: 10.3969/j.issn.1674-0696.2021.04.17 Abstract ( )   PDF (1135KB) ( )   Cylindrical specimens of =H=50 and 100 mm, dry density ρ=1.64, 1.74, 1.84 g/cm3, initial moisture content w=8.8%, 10.8%, 12.8%, were prepared by taking the expansive remolded mudstone with particle size smaller than 5mm in Chengde, Hebei province as the raw material. The axial expansion force Pax of the specimen and the circumferential expansion force Pcir were tested by the self-designed test equipment. The remolded mudstone specimens with =H=100 mm were soaked in alkaline simulated groundwater, acid simulated rainwater, and distilled water for 2 hours, and their Pax were tested; and the influence of specimen size, ρ, w and environmental water state on the Pax of remolded mudstone specimen was studied. Orthogonal method was used to analyze the sensitivity of ρ, w and environmental water state and pretreatment method to the influence of the axial and circumferential expansion forces of remolded mudstone specimen; and the variation rule of Pax and Pcir of the remolded mudstone specimen of the allowable micro-deformation rate Δ=0%, 1%, 2%, 3%, 4%, 5%, ρ=1.84 g/cm3, w=8.8%, =H=100 mm was studied. The results show that the Pax of =H=100 mm remolded mudstone specimens is 7.56% to 26.01% smaller than that of =H=50 mm. The Pax of specimens with two sizes decrease with the increase of w and increase with the increase of ρ; the Pax of the specimen soaked in alkaline simulated groundwater is 1.4~1.9 times larger than that of distilled water, while the Pax of the specimen soaked in acid simulated rainwater and Pcir is basically the same as the distilled water immersion; among the four factors, the pretreatment method is the main factor that affects Pax and Pcir. The more pre-disintegration times, the smaller the Pax and Pcir. The Pcir can be reduced by about 80% with 5% addition of cement; increasing Δ can effectively reduce the Pax and Pcir. When Δ is increased from 0% to 5%, the Pax and Pcir are reduced by 72.5% and 53.9% respectively. References | Related Articles | Metrics

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Phosphorus Form Transformation and Removal Efficiency in P-SMFC System AI Hainan1, ZHOU Manyu 1, ZHOU Tao2, ZHAN Hao1, LYU Yitao1 2021, 40(04): 118-126.  DOI: 10.3969/j.issn.1674-0696.2021.04.18 Abstract ( )   PDF (1152KB) ( )   The P-SMFC system was constructed with the lake sediment with serious eutrophication as the bottom material and the overlying water with TP concentration of 0.2 mg/L. The effects of plant black algae on the phosphorus removal efficiency, the transformation characteristics of phosphorus form and the power generation performance in the P-SMFC system were investigated. The test results show that: after 240 hours, the voltage of the SMFC system reaches 68.5 mV and is stable, which starts successfully. The output voltage of P-SMFC system with and without plants are 69mV and 50 mV respectively, the current and power density are 52.56 mA/m2 and 3.92 mW/m2, 42.40 mA/m2 and 2.54 mW/m2 respectively; the cumulative removal rates of total phosphorus, total phosphorus in sediment and organic matter in P-SMFC system with plants are 76.5%, 38.75% and 82.89%, respectively, which are 42.5%, 29.17% and 77.78% higher than of those of SMFC system without plants. It is indicated that the addition of plants promotes the power generation process and greatly improves the phosphorus removal efficiency, but the ability to improve the organic matter removal efficiency is limited. Through studying the change of phosphorus form, it is proved that the addition of plants promotes the mineralization of organic phosphorus, and the contents of Ca-P, Al-P and Fe-P in P-SMFC system with plants are higher those in P-SMFC system without plants. References | Related Articles | Metrics

Transportation Equipment

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Curve Negotiation Performance of Linear Motor Straddle Monorail Vehicle DU Zixue, WU Haoxin, YANG Zhen 2021, 40(04): 127-132.  DOI: 10.3969/j.issn.1674-0696.2021.04.19 Abstract ( )   PDF (1876KB) ( )   In view of the problem that the running wheel of Chongqing straddle monorail line 3 started to slip on the steep road during the operation in rainy and snowy days, the linear motor straddle monorail was designed, which was extended to the “three high” areas with extreme cold temperature in winter, high temperature in summer and high latitude. The dynamics model of linear motor straddle monorail vehicle was established by structure design. Through dynamic simulation analysis, it is proved that the proposed design has good curve negotiation performance and air gap stability, but its curve speed limit should be lower than that of straddle monorail. References | Related Articles | Metrics

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Combined Control Method of Intelligent Vehicle Longitudinal and Lateral Motion DENG Tao1, LI Xin2 2021, 40(04): 133-140.  DOI: 10.3969/j.issn.1674-0696.2021.04.20 Abstract ( )   PDF (994KB) ( )   Aiming at the multiple complex dynamic constraints and performance requirements in intelligent vehicle motion control, a lateral and longitudinal control combined method based on model predictive control (MPC) was proposed, and the lateral and longitudinal controllers were designed respectively. The lateral controller was based on the monorail dynamic model and the longitudinal controller adopted the hierarchical control structure. Taking the longitudinal velocity as the coupling point, the lateral and longitudinal controllers were combined. According to the path information, the vehicle speed was planned, and the steering and speed were controlled at the same time. Finally, the co-simulation was carried out by CarSim and MATLAB. The test results show that the controller has good tracking performance, strong real-time performance and can meet the requirements of vehicle lateral stability, comfort and ride comfort. References | Related Articles | Metrics

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Components Durability Test Conditions Based on Driving Condition LI Yaohua, LIU Yang, SONG Weiping, SHAO Pandeng, REN Tianyuan 2021, 40(04): 141-146.  DOI: 10.3969/j.issn.1674-0696.2021.04.21 Abstract ( )   PDF (4126KB) ( )   Aiming at the problem that the acquisition process of automobile components durability test condition was complex, a method to analyze the components durability test condition through the actual driving condition was proposed. Based on the actual operation data of a pure electric bus in Xi’an, the driving condition was constructed. According to the actual parameters of the vehicle, the vehicle simulation model was established, and the stress load condition of the motor output shaft based on the actual driving condition was simulated and calculated. The damage calculation method of motor output shaft under different load was obtained according to the liner fatigue cumulative damage theory and the material S-N curve of motor output shaft. The four-peak-valley rain-flow counting method was used to calculate the damage of motor output shaft under different stress load conditions, and the corresponding cycle life was obtained. The motor speed condition and torque condition corresponding to driving cycle with the shortest life were selected as the motor output shaft durability test condition. References | Related Articles | Metrics