&lt;TPL-PCRUN&gt; Statement of methods

Zhou, Ning; Lv, Qingsong; Yang, Yi; Zhang, Weihua

doi:10.1080/00423114.2014.982136

Cited by 21 publications

(8 citation statements)

References 9 publications

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“…This is due to the unilateral non-linearity exhibited by the droppers, which tend to slacken and make the catenary more flexible. Comparing the optimal catenary configurations with respect to their reference configura- (13) This coefficient is calculated for all the eight catenaries, as shown in Table 7. A large decrease of the stiffness variability is noticed in the optimal Benchmark catenaries if compared with the reference configuration.…”

Section: Static Characteristics Of the Optimal Catenariesmentioning

confidence: 99%

“…This explains why in recent years a lot of effort has been put into developing accurate models capable of simulating the dynamic pantograph-catenary interaction. Among the vast diversity of studies found in the literature, [3][4][5][6][7][8][9][10][11][12][13] deserve special mention as they participated in a benchmark [14], and give a good insight into the present state of the art.…”

Section: Introductionmentioning

confidence: 99%

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An approach to geometric optimisation of railway catenaries

Gregori

Tur

Nadal

et al. 2017

Vehicle System Dynamics

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The quality of current collection becomes a limiting factor when the aim is to increase the speed of the present railway systems. In this work an attempt is made to improve current collection quality optimising catenary geometry by means of a Genetic Algorithm. As dropper lengths and dropper spacing are thought to be highly influential parameters they were chosen as the optimisation variables. The results obtained show that a Genetic Algorithm can be used to optimise catenary geometry to improve current collection quality measured in terms of the standard deviation of the contact force. Furthermore, it is highlighted that apart from the usual pre-sag, other geometric parameters should also be taken into account when designing railway catenaries.

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Section: Static Characteristics Of the Optimal Catenariesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

An approach to geometric optimisation of railway catenaries

Gregori

Tur

Nadal

et al. 2017

Vehicle System Dynamics

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“…In fact, effort has been made to minimize such fluctuations through optimization of the elements used in the pantograph or catenary system. A multitude of software programs written in this field in recent years reflects the importance of the issue [2][3][4][5][6][7][8][9][10][11]. In addition, part of the researches are concentrated with controlling the pantograph through the estimation of the level of force via various methods and prevent any significant changes by applying controlling forces [12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Using new analytical algorithm to study the effect of temperature variations on static shape of contact wire of OCS

Vesali¹,

Molatefi²,

Rezvani³

2016

J. vibroeng.

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The vibrations of pantograph passing underneath the overhead system can be reduced by using droppers to place the contact wire in the designed curve. Nowadays, various software programs are used to estimate dynamic interaction of pantographs and overhead catenary system. In order to implement the software program, the necessary static force for each dropper should be estimated initially to place the contact wire in the designed curve. Unlike most available software programs, the implemented software program in this research consists of a heuristic analytical algorithm to estimate the static shape of the overhead catenary system. Accordingly, the variable separation and eigen function expansion method were used to calculate the static shape of contact wire and messenger cable under a given loading condition. At the next step, the stiffness matrix of contact wire in catenary was obtained and a procedure was defined to calculate the necessary static force for each dropper, which would then place the contact wire in the target curve. Finally, effort was made to examine the function of automatic tension device in OCS (Tension Wheel considering the Coulomb's friction). Moreover, the deformations in the contact wire and messenger cable due to temperature changes were estimated and the results shows that allowable friction in the tension wheel can cause 27 % deviation in sag of the contact wire.

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“…Other iterative methods, such as the negative-sag method applied in [34] or the one used in [21,33], are based on linear formulations and proceed by modifying the dropper lengths at each step of the procedure. Analytic expressions for calculating length of droppers and pre-sag of messenger wire are also found in [43].…”

Section: Initial Configuration Problemmentioning

confidence: 99%

“…Although some authors do not allow for dropper slackening [24][25][26][27][28][29][30], it is an important feature that should be regarded in the models as stated in [31], where experimental curves of dropper behaviour are provided. Due to the low bending stiffness of these elements, most dropper models are based on either a mass-spring-damper system with slackening [20,[32][33][34] or a bar element with slackening [22,[35][36][37][38]. These two options are also used to model steady arms [31].…”

Section: Catenary Modellingmentioning

confidence: 99%

Efficient simulation of the pantograph-catenary dynamic interaction. Catenary optimisation and installation error analysis

Verdú¹

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Dr. Vocal:Dr.Secretary: Dr. Valencia, May 2018 AbstractModelling and simulation of the dynamic interaction between pantograph and catenary has become a powerful tool to expedite the catenary design process since, among other advantages, it helps in reducing the number of the costly experimental in-line tests.In order to tackle these numerical simulations, in this Thesis the catenary system is modelled by the Finite Element technique, based on the absolute nodal coordinates formulation, while a simple lumped-mass model is used for the pantograph. The interaction between the two systems is accomplished with a penalty formulation. After solving the initial nonlinear configuration problem, the equation of motion is linearised with respect to the static equilibrium position and it is then solved in time by applying the Hilber-Hughes-Taylor (HHT) time integration method. However, dropper slackening and pantograph contact losses are two sources of nonlinearities which must be considered in the solution procedure at the expense of an increase in the computational cost.The main objectives of this Thesis are both to find optimal catenaries in terms of current collection quality and to analyse the effect of installation errors in the dynamic behaviour of the system. To achieve these goals, it is mandatory to perform a large number of pantograph-catenary dynamic simulations for which the computational cost can become prohibitive.In order to reduce this computational effort, the first proposal made in this Thesis is to precompute a parametric solution of the pantograph-catenary dynamic interaction for all values of the design variables, by means of the Proper Generalised Decomposition (PGD) technique. Thus, the dynamic response of the system would be instantly available when it is requested by the optimisation or the stochastic algorithms. If dropper lengths are considered as design variables, this parametric approach is successful when applied to the static equilibrium problem. Nevertheless, in the dynamic case, when dropper slackening is considered, the solution exhibits a vii great sensitivity to small changes in the parameters and therefore, a huge number of PGD modes are required to obtain the parametric solution with enough accuracy.The impossibility of having a parametric solution leads the author to propose a fast strategy to simulate the dynamic interaction problem, providing remarkable saves in computational cost. The method is divided into two stages which are based on moving the nonlinear terms to the right hand side of the dynamic equation. In the first stage, the response of the system under unitary forces is precomputed and stored. Then, in the second stage of the method, the treatment of the nonlinearities is condensed into a small system of equations, whose unknowns are now the forces associated with the nonlinearities instead of the nodal displacements of the whole system.With this proposed algorithm, it is possible to carry out efficient optimisations of the catenary geometry. Specifically, contact wire he...

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<TPL-PCRUN> Statement of methods

Cited by 21 publications

References 9 publications

An approach to geometric optimisation of railway catenaries

An approach to geometric optimisation of railway catenaries

Using new analytical algorithm to study the effect of temperature variations on static shape of contact wire of OCS

Efficient simulation of the pantograph-catenary dynamic interaction. Catenary optimisation and installation error analysis

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