排序方式: 共有8条查询结果,搜索用时 31 毫秒
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采用CFD分析法,对弓头及其支架连接区域的涡流结构和噪声源结构进行了分析,指出改进型支架与最佳型弓头组合对降低受电弓的空气动力噪声非常有效. 相似文献
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Mitsuru Ikeda 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2015,53(3):357-369
Gasen-do FE is a simulation software for pantograph/catenary dynamic interaction analysis. Gasen-do FE is based on the non-linear finite element method, and its code is implemented in Matlab. This program corresponds to 2D and 3D models of simple and compound catenaries. Steady arms and catenary suspension equipments such as droppers and hangers are modelled as bar elements taking into consideration the tangential stiffness due to their geometrical non-linearity. It is possible to simulate the effect of slackening of droppers and hangers. This paper will introduce the computational algorithm of this program and the validation result by comparing with experimental data. 相似文献
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To study the effect of different transport policies on reducing the average comprehensive travel cost (CTC) of all travel modes, by increasing public transport modal share and decreasing car trips, an optimization model is developed based on travel cost utility. A nested logit model is applied to analyze trip modal split. A Genetic Algorithm is then used to determine the implementation of optimal solutions in which various transport policies are applied in order to reduce average CTC. The central urban region of Beijing is selected as the study area in this research. Different policies are analyzed for comparison, focusing on their optimal impacts on minimizing the average CTC utility of all travel modes by rationally allocating trips to different travel modes in the study area. It is found that the proposed optimization model provides a reasonable indication of the effect of policies applied. 相似文献
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Stefano Bruni Jorge Ambrosio Alberto Carnicero Yong Hyeon Cho Lars Finner Mitsuru Ikeda 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2015,53(3):412-435
This paper describes the results of a voluntary benchmark initiative concerning the simulation of pantograph–catenary interaction, which was proposed and coordinated by Politecnico di Milano and participated by 10 research institutions established in 9 different countries across Europe and Asia. The aims of the benchmark are to assess the dispersion of results on the same simulation study cases, to demonstrate the accuracy of numerical methodologies and simulation models and to identify the best suited modelling approaches to study pantograph–catenary interaction. One static and three dynamic simulation cases were defined for a non-existing but realistic high-speed pantograph–catenary couple. These cases were run using 10 of the major simulation codes presently in use for the study of pantograph–catenary interaction, and the results are presented and critically discussed here. All input data required to run the study cases are also provided, allowing the use of this benchmark as a term of comparison for other simulation codes. 相似文献
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Budi S. Prasodjo Kimio Saito Yasushi Higo Hisashi Nobukawa Katsuya Maeda 《Journal of Marine Science and Technology》2006,11(4):260-269
This article discusses the dynamic responses of a coastal cargo ship that consists of unit modules with advance forward speed
in waves. We introduce a simple way of connecting the modules that has enough capability to link the modular parts of the
ship as a unified whole. The flexible connection consists of male and female rubber fenders with additional pretensioned ropes.
This kind of connection system is proposed for use in coastal regions with relatively calm waters wherein the modular ship
can move at a moderate speed. The modules are assumed to be rigid compared to the connections. Computations were performed
to investigate the vertical elastic responses of four modules connected end-to-end with the assumption that in the simple
hinge, no gaps occur in the flexible rubber connections between adjacent modules. A simple method, which is an extension of
the computational analysis we reported previously, is presented to study the hydroelasticity and rope tension forces of the
modular ship with forward speed in waves. Experiments with a three-dimensional model at Froude numbers of 0 and 0.16 in head
waves were performed to evaluate the effectiveness of the calculation method. In the experiments, deflections for each part
were measured using calibrated potentiometers. Force transducers were used to measure the rope tension force between the modules
of the articulated cargo ship. Some slight differences were observed, but generally the calculated results showed the same
trends as the experimental values. 相似文献
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Application of a genetic algorithm to the optimal structural design of a ship's engine room taking dynamic constraints into consideration 总被引:4,自引:0,他引:4
Mitsuru Kitamura Hisashi Nobukawa Fengxiang Yang 《Journal of Marine Science and Technology》2000,5(3):131-146
The genetic algorithm, known as GA, is used to optimize engine room structure, not only under static constraints, but also
under dynamic constraints. A penalty function method is used to handle the complicated constraint conditions based on the
numerical results of dynamic and static analyses. There are several ways to take the dynamic effect into account in the optimum
design of ship structure. First, the inequality constraint condition is applied to separate the natural frequency and the
exciting frequency. Second, generalized design variables are introduced in order to transfer not only the dynamic but also
the static equilibrium equations into the equality constraints, resulting in the optimal structural design without the need
to solve these equilibrium equations. Third, the magnitudes of the acceleration and displacement are constrained instead of
applying the natural frequency constraint condition. In order to achieve better convergency in the optimization with least
resources, several operators and methods are considered and then introduced into the structural design of the engine room.
The new operator, called either objective elitism or fitness elitism, is introduced to improve the efficiency of the method.
The effect of boundary mutation and nonuniform mutation on the performance of the GA is examined. Not only binary representation
but also floating-point representation are used to express the design gene in the GA. Fuzzy theory is applied in the GA to
handle the uncertainty of the constraint conditions. Two ways of solving fuzzy optimization are investigated in order to obtain
a fuzzy solution and a crisp solution.
Received: October 2, 2000 / Accepted: November 30, 2000 相似文献
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J. Takahashi M. Yamakado S. Saito 《International Journal of Automotive Technology》2013,14(6):921-926
This paper describes the development of the braking assistance system based on a “G-Vectoring” concept. The present work focuses in particular on “Preview G-Vectoring Control” (PGVC), which is based on the “G-Vectoring Control” (GVC) scheme. In GVC, the longitudinal-acceleration control algorithm is based on the actual lateral jerk. PGVC decelerates a vehicle before it enters a curve, and is based on a new longitudinal-acceleration control algorithm which uses predicted and actual lateral jerk. Using the predicted lateral jerk makes it possible to decelerate the vehicle prior to curve entry. This deceleration can emulate a driver’s deceleration as the vehicle approaches a curve entry. PGVC is based on such deceleration algorithms and enables automatic deceleration similar to the action of a driver. It is thus possible to significantly improve the driver’s feeling when this system is activated. Driving tests with this new control system on snowy-winding course confirmed that the automatic brake control quality improved considerably compared to manual driver control considering both lap time and ride quality. These results indicate that PGVC can be a useful braking assistance system not only to improve the driver’s handling performance but also to reduce the brake-task during driving on winding roads. 相似文献
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