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08 October 2018, Volume 37 Issue 10 Previous Issue    Next Issue
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Bridge & Tunnel Engineering
Highway & Railway Engineering
Port & Waterway · Hydraulic & Hydroelectric · Resources & Environment
Traffic & Transportation Engineering
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Bridge & Tunnel Engineering

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Bridge Structure Damage Identification Based on the Damage Performance Function CHEN Dongjun1, 3, LI Tianhua2, PENG Kai3, ZHANG Kejia2, LIN Jieqiong3, BAI Wenying2 2018, 37(10): 1-7.  DOI: 10.3969/j.issn.1674-0696.2018.10.01 Abstract ( )   PDF (524KB) ( )   Taking slab bridge as the research object, the finite element models of intact and cracked slabs were established respectively. With various live loads of random running vehicle excitations, the acceleration time-history responses at the measuring points were calculated, and the acceleration time-history was piecewise in the time domain, and spectrum analysis was carried out to get the spectrum. A probabilistic statistical algorithm was developed to deal with the problem of uncertain damage identification. Based on the probabilistic significance of the reduction of the natural frequency after plate damage and the statistical characteristics of the indication frequency under various working conditions, the performance function of plate damage identification was established. The structural damage state was expressed by the damage performance function, and the probability of different structural damage states was calculated. The calculated results agree well with the development trend of structural cracking and crack extension. References | Related Articles | Metrics

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Dynamic Characteristics and Influence Factors of Pre-stressed Concrete Continuous Beam Bridge REN Xiang, TAN Xiao, SONG Fei, QI Haipeng, MA Min 2018, 37(10): 8-12.  DOI: 10.3969/j.issn.1674-0696.2018.10.02 Abstract ( )   PDF (556KB) ( )   In order to find out the causes of deviation between first-order frequency of dynamic load test of some new bridges and the theoretical calculation results, based on the dynamic load test of a pre-stressed concrete cross-section continuous beam bridge, the first-order frequency and vibration mode of the bridge under fluctuating load were measured; meanwhile, the finite element model was established. The theoretical value of the first-order frequency of bridge was calculated, and the two were compared. The influence of 4 factors such as common longitudinal steel bar, pre-stressed steel bar, guardrail and dynamic elastic modulus of concrete on the dynamic characteristics of bridge was analyzed. The results show that the measured value and theoretical value of the first-order frequency are 1.760 Hz and 1.395 Hz respectively, whose deviation is about 21%. Taking the factors such as common longitudinal steel bar, pre-stressed steel bar, guardrail and dynamic elastic modulus of concrete into the finite element model respectively, the first-order frequency of the structure are 1.416Hz, 1.413 Hz, 1.384 Hz and 1.634 Hz respectively; and the first-order frequency is 1.684 Hz when the above four factors are considered comprehensively. Based on the above analysis results, among 4 influence factors, the dynamic elastic modulus of concrete has the most significant influence on the first-order frequency of the structure; and other factors have less influence, which may not be considered. It is suggested that when the bridge fundamental frequency is used to evaluate structure stiffness, the dynamic elastic modulus of concrete should be calculated in the finite element model, which makes the results closer to the actual state. References | Related Articles | Metrics

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Reasonable Stiffness Limits for Long-Span Track Suspension Bridge LIU Anshuang1, LI Xiaogang1, 2, GUO Xiangrong3, DING Peng2, QI Yong1 2018, 37(10): 13-20.  DOI: 10.3969/j.issn.1674-0696.2018.10.03 Abstract ( )   PDF (570KB) ( )   In existing design codes at home and abroad, there is a lack of stiffness limits for the long-span track suspension bridge. Based on the criteria of stiffness limits for small-span and medium-span track bridge, the stiffness setting and the operation state of long-span suspension bridge in service were investigated and summarized. The suggestion for reasonable stiffness limit of long-span track suspension bridge was proposed. Then, the finite element method of bars and the vibration analysis method of wind-vehicle-bridge coupling were adopted. The static characteristics and dynamic response of bridge as well as train running performance were evaluated through the application of engineering examples; and the rationality of stiffness limit was verified. The results show that for the long-span track suspension bridge, the vertical stiffness should be 1/300~1/500, the double vertical angle of the beam-end limit should be 9.0×10-3 rad, the unilateral limit should be 4.5×10-3rad, and the vertical acceleration should not be greater than 3.5 m/s2. Also, the transverse stiffness should be 1/600~1/1 200, the double transverse angle of the beam-end limit should be 6.0×10-3 rad, the unilateral limit should be 3.0×10-3 rad, and the transverse acceleration should not be greater than 1.4 m/s2. References | Related Articles | Metrics

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Optimal Schemes of Bridge Construction Based on Weighted Rank Sum Ration Method LIU Xiaojia1, 2, ZHANG Ke1 2018, 37(10): 21-25.  DOI: 10.3969/j.issn.1674-0696.2018.10.04 Abstract ( )   PDF (423KB) ( )   In order to solve the problem that bridge construction scheme mostly relied on subjective experience of experts  judgment and selection model of common bridge construction schemes was complex and cumbersome, the optimization model of bridge construction scheme based on weighted rank sum ratio (RSR)method was proposed. Firstly, the construction index system of bridge was built on the basis of consulting experts, senior designers and construction workers, and cloud theory was used to achieve quantitative transformation of qualitative indicators of each plan. Then, the entropy weight method was used to determine the index weight of the construction scheme. Finally, the weighted RSR model based on entropy method was established; and the construction schemes of bridge were sorted and divided into files to select out the optimal one. Cloud theory could achieve the quantitative transformation of qualitative indicators, which could fully consider the fuzziness and randomness of experts understanding of qualitative indicators. The entropy weight method was used to determine the weight of the scheme index, which could effectively avoid the subjective problem. The proposed weighted RSR model had advantages such as simple calculation process, no consideration of the index dimension as well as fast and reliable scheme selection. Through the example analysis, the results show that the proposed model can not only simplify the selection of bridge construction scheme but also effectively improve the objectivity of the scheme screening. References | Related Articles | Metrics

Highway & Railway Engineering

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Pavement Performance of Polypropylene Fiber Reinforced High Performance Concrete MA Shibin, XU Wenbin, XU Yanwei, YANG Xinwei 2018, 37(10): 26-30.  DOI: 10.3969/j.issn.1674-0696.2018.10.05 Abstract ( )   PDF (437KB) ( )   In order to study the effect of polypropylene fiber on pavement performance of high performance concrete, different amount of polypropylene fiber was added into the high performance concrete mixed with fly ash and mineral powder. The influence of polypropylene fiber content on the workability, mechanical strength and impact resistance of high performance concrete was studied by means of slump, compressive strength, flexural tensile strength and impact resistance test. Meanwhile, the impermeability, shrinkage and fatigue characteristics of polypropylene fiber reinforced high performance concrete were studied by means of rapid chloride migration, dry shrinkage and bending fatigue tests. The results show that the higher the amount of polypropylene fiber, the lower the workability and compressive strength of high performance concrete. Polypropylene fiber can significantly improve the flexural tensile strength and impact toughness of high performance concrete, improve the impervious capacity and fatigue life of high performance concrete and reduce drying shrinkage deformation. The research results can provide reference for the application of polypropylene high performance concrete in road engineering. References | Related Articles | Metrics

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Structure Life of Highway Pavement Frohmut Wellner1, LIANG Naixing2 2018, 37(10): 31-36.  DOI: 10.3969/j.issn.1674-0696.2018.10.06 Abstract ( )   PDF (541KB) ( )   Current pavement structure design and material composition design lack of consideration for influence factors such as traffic load growth and environmental climate change. Aiming at this problem, the influence of asphalt, the asphalt mixture and the interlayer bonding strength of asphalt pavement on the fatigue life of asphalt pavement was analyzed; and the influence of above factors on pavement structure design and material composition design was also analyzed. Finally, a solution was proposed. The proposed solution puts forward a new idea for pavement structure analysis and design. References | Related Articles | Metrics

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Stability Analysis of Road Slope Under Rainfall Condition HE Yuqiong1, LI Chunming1, YANG Xinghua2, HUANG Xi1 2018, 37(10): 37-42.  DOI: 10.3969/j.issn.1674-0696.2018.10.07 Abstract ( )   PDF (1165KB) ( )   Rainfall is the main predisposing factor of landslide in the factors such as man-made disturbance, earthquake and rainfall. Combing with the data of geological survey, drilling, geophysical prospecting, field investigation, laboratory test and data collection, Xinping-Daga Highway slope in Yuxi was taken as the research site, and the infinite slope model, the Sweden slice method and the limit equilibrium method were used to calculate and analyze the flowrate, the flow direction and the stability coefficient of the slope under rainfall conditions. The stability of the slope before and after excavation was studied and the area where the water erosion was serious was predicted. The results show that the slope is in a steady state before the excavation when the water level height is equal to the soil thickness under ultimate saturation. After excavation with the slope ratio of 1: 1.75, the slope is also in a stable state. Therefore, the slope excavation construction is safe, but it is necessary to do well drainage and protection work on slope. References | Related Articles | Metrics

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Construction Mechanics of Construction Passage into Subway Station with Application of Door-Type-Conversion Method WANG Lingping1, WANG Mingjun1, ZHAO Xiangzhong1, MU Xinhao1, Guo Zhiqiang 2 2018, 37(10): 43-48.  DOI: 10.3969/j.issn.1674-0696.2018.10.08 Abstract ( )   PDF (973KB) ( )   Based on Hongtudi Station in line 10 of Chongqing rail transit, the method combing finite element numerical simulation with monitoring measurement was adopted. The influence of door-type-conversion climbing construction method on the construction passage and the stability of surrounding rock and supporting structure at intersection of subway station was analyzed. The results show that the construction of door-type-conversion method has great influence on the displacement and stress of the surrounding rock of the transition section. The vertical displacement of the surrounding rock at intersection is 8.3 mm~10.7 mm; the maximum principal stress of surrounding rock is 7.92 MPa (pressure stress)and the minimum principal stress is 0.64 MPa (tensile stress); the maximum principal stress of the supporting structure is 21.40 MPa (compressive stress)and the minimum principal stress is 6.30 MPa (tensile stress). The minimum principal stress exceeds the tensile strength of concrete, which should be paid enough attention in the construction process. References | Related Articles | Metrics

Port & Waterway · Hydraulic & Hydroelectric · Resources & Environment

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Status Quo and Trend of Unstable Rock Stability Analysis CHEN Hongkai, QIN Xin 2018, 37(10): 49-60.  DOI: 10.3969/j.issn.1674-0696.2018.10.09 Abstract ( )   PDF (686KB) ( )   Dangerous rock collapse is the main geological disaster type in the Three Gorges Reservoir area and even in the whole western region. It has such basic characteristics as extensive nature, suddenness, concealment and disaster severity. Based on the search and analysis of research literature at home and abroad and combined with the authors research practice in the Three Gorges Reservoir area for many years, the research status of unstable rock stability analysis was generalized into four aspects, i. e, unstable rock formation mechanism, stability calculation method of unstable rock, stability evaluation method of unstable rock and application of numerical analysis. By systematically combing the research in every aspect, it is found that both domestic and foreign scholars have focused on the problem of plane propagation of crack at the end of main structure surface of unstable rock; the influence mechanism of stability and deformation characteristics of unstable rock has been systematically studied, but the spatial form of unstable rock is not considered; there is a lack of research on the three-dimensional fracture stability of the main control structures where the surrounding area is penetrating and the middle region is not penetrating. In addition, it is pointed out that 3 research directions in the further study of unstable rock stability analysis should be focused, namely, the three- dimensional fracture expression of the unstable rock failure, the prediction of unstable rock stability and the monitoring and early warning technology for unstable rock stability. References | Related Articles | Metrics

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Stability Analysis of Bedding Rock Slope Based on Double Strength Reduction Method GUO Jianjun1, 2 2018, 37(10): 61-66.  DOI: 10.3969/j.issn.1674-0696.2018.10.10 Abstract ( )   PDF (414KB) ( )   With the limit equilibrium method, the bedding rock slopes were analyzed by double strength reduction method, and the amplification ratio of reduction coefficient was proposed. According to the principle that the shear strength reduction was determined by the amplification ratio, the limit reduction coefficient was obtained when the slope reached the limit state. Taking the depth of tension crack and the depth of water filling as a single variable respectively, the influence degree of internal friction angle and cohesive force on the stability of rock slope was compared and analyzed when the slope stability changed. Finally, the weighted safety coefficient of slope was defined by limit reduction coefficient in the double strength reduction method. The results show that: the influence degree of internal friction angle and cohesive force on rock slope can be taken into account by the double strength reduction method. The double parameter reduction analysis is carried out on the bedding rock slope, and the reduction coefficient of the internal friction angle in double parameter reduction is defined as the slope safety coefficient. This result is more in line with the practical engineering, and can provide reference for the same kind of problems. References | Related Articles | Metrics

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Development,Utilization and Monitoring Status of Shallow Geothermal Energy in Chongqing ZHU Shibao, PENG Qingyuan, LIU Gang, HE Yuan, LI Shuangcai 2018, 37(10): 67-72.  DOI: 10.3969/j.issn.1674-0696.2018.10.11 Abstract ( )   PDF (695KB) ( )   Based on the related research results of the shallow geothermal energy carried out by Nanjiang hydrogeological and engineering geology brigade of Chongqing Geology and Mineral Exploration Bureau in recent years, taking the Nanjiang geology brigade monitoring station of Chongqing Geology and Mineral Exploration Bureau as an example, the geo-temperature monitoring data for the last 6 years was analyzed and summarized. The average original geothermal temperature, the constant temperature layer and the average geothermal temperature of the constant temperature layer at different regions in the monitoring area were different; and their relationships between topography, groundwater activity and formation lithology of monitoring sites were obtained. The present situation and achievements of shallow geothermal energy in Chongqing were expounded. References | Related Articles | Metrics

Traffic & Transportation Engineering

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Service Level Evaluation of Online Taxi Booking Based on Matter-Element Method REN Qiliang, ZHOU Lijie 2018, 37(10): 73-79.  DOI: 10.3969/j.issn.1674-0696.2018.10.12 Abstract ( )   PDF (466KB) ( )   The level of service is the key to the survival, healthy competition and harmonious development of future online taxi booking companies. High quality of online taxi booking services can not only meet residents different travel demand, but also play an important role in easing traffic congestion and achieving sustainable urban development. In order to evaluate online taxi booking services scientifically and systematically and analyze the features of online taxi booking services deeply, an evaluation index system of online taxi booking services was established from five perspectives such as service reliability, service responsiveness, service security, service comfortability and service flexibility, which stood from the users point of view. And then the fuzzy matter-element evaluation model was selected to evaluate the service level of online taxi booking in big city. The service of online taxi booking in Chongqing was taken as an example to provide theoretical and practical basis for upgrading the service level of online taxi booking in China. References | Related Articles | Metrics

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Ridership Characteristics Analysis of the Long-Distance Bus Based on Smart Card Data ZHOU Yuyang1, 2, ZHAO Qianyang1, CHEN Yanyan1, 2, YAO Lin1, ZHAO Jin1, XIONG Jie1, 2 2018, 37(10): 80-85.  DOI: 10.3969/j.issn.1674-0696.2018.10.13 Abstract ( )   PDF (662KB) ( )   Focused on the space-time characteristics of the long-distance bus passenger flow, five indexes were proposed to establish the evaluation system based on bus IC card data. Five indexes included imbalance index, peak time ratio, the direction unbalanced coefficient, density of bus resources along routes and average mileage utilization coefficient of routes. Four long-distance bus lines in Beijing and Hebei province were selected in the case study and the evaluation radar map was given. The results show that the proposed index system can effectively quantify, analyze and evaluate the passenger flow characteristics of the long-distance bus; and then it can provide optimization suggestions for the operation and management. The calculation results of the case study show that the values of the above five indexes of the bus lines in the city are all less than those of the rural bus lines. For the bus lines with a high average line utilization and unbalance coefficient, such as bus Line 815, the shuttle bus or nonstop scheduling could improve the operation efficiency. The lines with low bus line density and average line utilization, for example Line 915, the network can be optimized appropriately and the stations can be adjusted. References | Related Articles | Metrics

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Drivers Route Choice Behavior under Different Traffic Information Guidance ZHANG Weihua, LI Mengfan 2018, 37(10): 86-93.  DOI: 10.3969/j.issn.1674-0696.2018.10.14 Abstract ( )   PDF (711KB) ( )   According to the different traffic information contents provided by a text-type VMS board of a fast road in a typical road network, the drivers route choice behavior was investigated and studied, with the full consideration of the cognitive model of drivers. VMS message strategy experiments that included a single or multiple quantitative variables were designed and the traffic behavior data were collected through the stated preference (SP)survey. And then an orderly multi-classification Logistic regression model on the drivers route choice behavior was established. The results demonstrate that, even under the same traffic condition, the route choices made by the drivers are quite different when different types of information are provided; the information compliance rate that ranks from high to low is time saved by detour, detouring distance, traffic status and congested distance orderly. In addition, the accuracy, the completeness and the timeliness of the route traffic information released by VMS are the main factors that affect drivers route choice behavior. The above findings can provide a basis for formulating VMS information release strategy. References | Related Articles | Metrics

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Bicycle Riding Speed Influenced by Road Environment in Historic Districts WANG Qiuping，WANG Kai 2018, 37(10): 94-99.  DOI: 10.3969/j.issn.1674-0696.2018.10.15 Abstract ( )   PDF (542KB) ( )   On the basis of the concept of priority development of slow traffic in historic districts, 7 road environmental factors such as bicycle lane width and bicycle flow were summed up by taking bicycle riding speed as the dependent variable, and the Logistic model of the impact probability of various factors on the bicycle riding speed in historic districts was established. The results show that the factors such as bicycle lane width, bicycle flow and the number of the pedestrians are the main factors influencing the bicycle riding speed. When the bicycle lane width is increased by 1.0m, the impact probability of riding speed is reduced by 0.352 at most. The greater the number of bicycles and pedestrians is, the larger the probability of impact on cycling speed will be; and the impact probability will be increased by 0.250 at most for an increase of 100 persons per hour for a single lane. When the bicycle lane width is greater than 3.5 m (two-way)and the number of pedestrians on a single lane is less than 500 persons per hour, the bicycle riding speed is less affected so that the riding environment tends to be optimal. Therefore, the proposed model can better reveal the main factors that affect bicycle riding speed in historic districts and provide theoretical basis for slow traffic planning in blocks. References | Related Articles | Metrics

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Travellers Acceptability of the “Internet Plus Highway Passenger Transportation” WEN Huiying, MEI Jiajun 2018, 37(10): 100-109.  DOI: 10.3969/j.issn.1674-0696.2018.10.16 Abstract ( )   PDF (594KB) ( )   “Internet Plus” convenient traffic speeds up the deep integration of the internet and transportation. Firstly, in view of the characteristics of highway passenger travel behavior, the factors that affected the acceptability of “internet plus highway passenger transport” were analyzed. Secondly, based on the sample data of questionnaire survey on Guangzhou travelers acceptability of “internet plus highway passenger transport”, the travellers acceptability of current “internet plus highway passenger transport” ticketing system was analyzed by adopting the method of correlation analysis and cross analysis from three aspects, such as the modes of passenger to buy ticket, the frequency to view information by “internet plus” mode and the satisfaction to “internet plus” ticketing system. Finally, the orderly multi-classification Logistic regression model with cumulative probability was established to analyze its acceptability characteristics in the future development of “internet plus highway passenger transport” from four aspects, such as real-time scheduling, dynamic fare, carpooling and transfer as well as coupon mechanism, which aimed to explore the targeted development strategy of “internet plus highway passenger transport” to travelers. References | Related Articles | Metrics

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Resource Allocation of Expressway Emergency Vehicle in the Environment of Construction YU Dexin1, 2, ZHAO Yang1, WU Yi1, QU Weidong1 2018, 37(10): 110-116.  DOI: 10.3969/j.issn.1674-0696.2018.10.17 Abstract ( )   PDF (558KB) ( )   A resource allocation method of expressway emergency vehicle under construction environment was proposed.According to the analysis on the influence of construction area on highway capacity, the expressway risk degree calculation model under construction environment was established to get the risk degree of each section.According to the current expressway emergency resource allocation models,the influence of factors such as risk degree, the best rescue time and resource demands in the construction area was fully taken into account; the emergency resource allocation model based on the traffic capacity and historical accident data of the construction area was established and the particle swarm optimization algorithm was used to solve the proposed model.Taking the construction area of Jinan-Qinghai section of Shandong expressway as an example, the emergency vehicle resource allocation was carried out. The results show that under the premise of guaranteeing the resource demand of each section, the utilization efficiency of emergency vehicle is the highest, which realizes the reasonable allocation of expressway emergency vehicle under the construction environment. References | Related Articles | Metrics

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Clustering Analysis Method of Shipborne AIS Data Based on Spatio-Temporal Density LI Yongpan1, 2, LIU Zhengjiang1, ZHENG Zhongyi1 2018, 37(10): 117-122.  DOI: 10.3969/j.issn.1674-0696.2018.10.18 Abstract ( )   PDF (861KB) ( )   Shipborne AIS data contains location, time and other attributes, which belongs to typical spatio-temporal data. And the spatio-temporal clustering analysis on shipborne AIS data contributes to the data mining of maritime traffic characteristics. Considering the specific characteristics of AIS data, a time slicing method was proposed to effectively simplify the AIS data and deal with the problem of different report intervals. Based on DBSCAN algorithm, combining time and space attributes, a spatio-temporal clustering algorithm of shipborne AIS data was put forward, and the actual AIS data was taken for a case study. The proposed method can better take account of the spatial-temporal coupling characteristics of ship traffic flow and identify the hidden spatio-temporal pattern, which provides a new way for the competent authorities to carry out ship traffic management, optimize navigation order and ensure navigation safety. References | Related Articles | Metrics

Vehicle &Electromechanical Engineering

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Nonlinear Vibration Analysis of Electromechanical Coupling System of Pure Electric Tractor YAN Guojun1, 2, 3, YANG Yan1, GU Jianhua1, YAO Yueqin1, QI Miao1, 4 2018, 37(10): 123-132.  DOI: 10.3969/j.issn.1674-0696.2018.10.19 Abstract ( )   PDF (769KB) ( )   In allusion to the problem that the electromechanical coupling system of the pure electric tractor under the low speed and heavy load condition was affected by the non-periodic impact interference force, which produced the strong dynamic load, caused the nonlinear torsional vibration and had serious influence on the reliability and durability of the electromechanical coupling system of the pure electric tractor, the nonlinear torsional vibration model of electromechanical coupling system of pure electric tractor was established to solve the equilibrium point of the undisturbed Hamiltonian system, considering the coupling effect of rotor torsional angle and the electromagnetic torque. And the Melnikov method was adopted to calculate the bifurcation threshold curve, which further analyzed the influence of dynamic mechanical load on the nonlinear dynamic behavior of electromechanical coupling drive system of a pure electric tractor. The research results indicate that the electromechanical coupling drive system of pure electric tractor is characterized by the complex dynamic behaviors such as periodicity, quasi-period and chaos. If the dynamic mechanical load f<3.6, the system is a periodic motion; if 3.6 References | Related Articles | Metrics

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Aerodynamic Characteristics of Vehicle Body Based on Non-smooth Element Structure GAO Wei, CHENG Jiawang 2018, 37(10): 133-138.  DOI: 10.3969/j.issn.1674-0696.2018.10.20 Abstract ( )   PDF (1592KB) ( )   The numerical simulation of the flow field of the smooth surface MIRA stepped back model was carried out and verified by using the method of computational fluid dynamics. Based on the drag reduction theory of bionic non-smooth surface, the location and size of the concave non-smooth element were determined. The influence of the non-smooth element structure on the drag reduction characteristics was simulated and analyzed. The structure factors of concave element were optimized by orthogonal experimental design. The simulation results show that the drag reduction rate of the optimal structure combination can reach 10.54%. Finally, from three aspects such as pressure drag, induced drag and friction, the drag reduction mechanism of the optimal structure combination of concave non-smooth element before and after improvement was analyzed and compared; the drag reduction effect for the body was significantly improved. References | Related Articles | Metrics