摘要：Performance and reliability experiments on BJD-6100EV electric buses, jointlydeveloped by Beijing Institute of Technology and Beijing Public Transport Company, are *** power model of battery pack is established and maximum output power is analyzed. A permanentmagnetic direct current (PMDC) motor with enhanced windings is developed for the bus. Torque-speedcharacteristics of the motor are modeled and performance of electric bus is analyzed. Computationalmethod of the range of electric bus is proposed and discussed. Experiments show that electric buscan realize design requirements. Computational methods are verified with the help of field test. Itis expected that design and computation method will provide helpful reference to development ofelectric vehicles.

摘要：In order to more accurately examine developing trends in gross cargo throughput, we have modeled the probability distribution of cargo throughput. Gross cargo throughput is determined by the time spent by cargo ships in the port and the operating efficiency of handling equipment. Gross cargo throughput is the sum of all compound variables determining each aspect of cargo throughput for every cargo ship arriving at the port. Probability distribution was determined using the Wald equation. The results show that the variability of gross cargo throughput primarily depends on the different times required by different cargo ships arriving at the port. This model overcomes the shortcoming of previous models: inability to accurately determine the probability of a specific value of future gross cargo throughput. Our proposed model of cargo throughput depends on the relationship between time required by a cargo ship arriving at the port and the operational capacity of handling equipment at the port. At the same time, key factors affecting gross cargo throughput are analyzed. In order to test the efficiency of the model, the cargo volume of a port in Shandong Province was used as an example. In the case study the actual results matched our theoretical analysis.

摘要：Topology optimization is an effective method to obtain a lightweight structure that meets the requirements of structural *** the optimization results meet the actual needs mainly depends on the accuracy of the material properties and the boundary conditions,especially for a tiny Flapping-wing Micro Aerial vehicle(FMAV)transmission system manufactured by 3D *** this paper,experimental and numerical computation efforts were undertaken to gain a reliable topology optimization method for the bottom of the transmission ***,the constitutive behavior of the ultraviolet(UV)curable resin used in fabrication was ***,a numerical computation model describing further verified via *** optimization modeling considering nonlinear factors,***,friction and collision,was presented,and the optimization results were verified by both dynamic simulation and ***,detailed discussions on different load cases and constraints were presented to clarify their effect on the *** methods and results presented in this paper may shed light on the lightweight design of a FMAV.

摘要：For the purpose of improving efficiency and realizing start–stop function, an electric oil pump(EOP) is integrated into an 8-speed automatic transmission(AT). A mathematical model is built to calculate the transmission power loss and the hydraulic system leakage. Based on this model, a flow-based control strategy is developed for EOP to satisfy the system flow requirement. This control strategy is verified through the forward driving simulation. The results indicate that there is a best combination for the size of mechanical oil pump(MOP) and EOP in terms of minimum energy consumption. In order to get a quick and smooth starting process, control strategies of the EOP and the on-coming clutch are proposed. The test environment on a prototype vehicle is built to verify the feasibility of the integrated EOP and its control strategies. The results show that the selected EOP can satisfy the flow requirement and a quick and smooth starting performance is achieved in the start–stop function. This research has a high value for the forward design of EOP in automatic transmissions with respect to efficiency improvement and start–stop function.

摘要：This work presents an integrated pressure-tracking controller for a novel electro-hydraulic brake(EHB) system considering friction and hydraulic disturbances. To this end, a mathematical model of an EHB system, consisting of actuator and hydraulic sub-systems, is derived for describing the fundamental dynamics of the system and designing the controller. Due to sensor inaccuracy and measurement noise, a Kalman filter is constructed to estimate push rod stroke for generating desired master cylinder pressure. To improve pressure-tracking accuracy, a linear friction model is generated by linearizing the nonlinear Tustin friction model, and the unmodeled friction disturbances are assumed unknown but bounded. A sliding mode controller is designed for compensating friction disturbances, and the stability of the controller is investigated using the Lyapunov method. The performance of the proposed integrated controller is evaluated with a hardware-in-the-loop(HIL) test platform equipped with the EHB prototype. The test results demonstrate that the EHB system with the proposed integrated controller not only achieves good pressure-tracking performance, but also maintains robustness to friction disturbances.

摘要：This study investigates the influence of different pantograph parameters and train length on the aerodynamic drag of high-speed train by the delayed detached eddy simulation(DDES) method. The train geometry considered is the high-speed train with pantographs, and the different versions have 3, 5, 8, 10, 12, 16 and 17 cars. The numerical results are verified by the wind tunnel test with 3.6% difference. The influences of the number of cars and the position, quantity and configuration of pantographs on flow field around high-speed train and wake vortices are analyzed. The aerodynamic drag of middle cars gradually decreases along the flow direction. The aerodynamic drag of pantographs decreases with its backward shift, and that of the first pantograph decreases significantly. As the number of pantographs increases, its effect on the aerodynamic drag decrease of rear cars is more significant. The engineering application equation for the aerodynamic drag of high-speed train with pantographs is proposed. For the 10-car and 17-car train, the differences of total aerodynamic drag between the equation and the simulation results are 1.2% and 0.4%, respectively. The equation generalized in this study could well guide the design phase of high-speed train.

摘要：The hybrid tracked vehicles(HTV)usually adopt series hybrid powertrain with extra steering mechanism,which has relatively low transmission efficiency and reduces the flexibility of structural *** overcome the disadvantages,a new kind of single-mode powertrain has been *** power-split hybrid powertrain is composed of three planetary gear(PG)sets connected to one engine,left and right track outputs,and three *** proposed powertrain can realize steering while going forward by controlling the output torque on each side without extra steering mechanism or steering *** to the diversity of the connection way between components and planetary gear sets,a rapid configuration design approach is proposed for the design selection of *** automated dynamic modelling method can show the one-to-one correspondence with the selected feasible groups by establishing two characteristic matrices,which is more simple than other *** analytically-based method is proposed to classify all possible connection designs into several groups to decrease the searching scope with improved design ***,the optimal control strategy is used to find the design with optimal fuel economy under typical condition of *** case study is implemented by the proposed design approach which demonstrates better design performances compared with the existing series-hybrid HTV.

摘要：In order to overcome the limitations of traditional microperforated plate with narrow sound absorption bandwidth and a single structure,two multi-cavity composite sound-absorbing materials were designed based on the shape of monoclinic crystals:uniaxial oblique structure(UOS)and biaxial oblique structure(BOS).Through finite element simulation and experimental research,the theoretical models of UOS and BOS were verified,and their sound absorption mechanisms were *** the same time,the influence of multi-cavity composites on sound absorption performance was analyzed based on the theoretical model,and the influence of structural parameters on sound absorption performance was *** research results show that,in the range of 100-2000 Hz,UOS has three sound absorption peaks and BOS has five sound absorption *** frequency range of the half-absorption bandwidth(α>0.5)of UOS and BOS increases by 242% and 229%,*** with traditional microperforated sound-absorbing structures,the series and parallel hybrid methods significantly increase the sound-absorbing bandwidth of the sound-absorbing *** research has guiding significance for noise control and has broad application prospects in the fields of transportation,construction,and mechanical design.

摘要：长大铁路隧道受特殊地质条件影响可采用分岔隧道建造。然而,列车高速穿越这种复杂构型的隧道时所引起的空气动力学效应尚不清楚。为此,本文采用三维、可压缩、非定常的雷诺时均模型,模拟研究了高速列车从不同方向通过分岔隧道时引起的气动效应。研究内容主要包括入口隧道结构为单线隧道(STE)和双线隧道(DTE)两个运行环境下的车体表面和隧道壁面的压力波动、列车气动力和周围流场特征等。研究结果表明,相比STE场景,DTE场景下车体表面和单线隧道壁面的压力峰峰值更大,并且气动阻力能耗也更大,头车的平均阻力增大19.2%。然而,STE场景下列车的侧向力波动更剧烈,其峰值相比DTE场景增加26%。本文的研究发现可为特殊铁路隧道的设计和建造提供有价值的空气动力学参考。