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Numerical simulation and optimization of aerodynamic uplift force of a high-speed pantograph

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Railway Engineering Science 2022年第1期30卷 117-128页

作者： Zhiyuan Dai Tian Li Ning Zhou Jiye Zhang Weihua Zhang State Key Laboratory of Traction Power Southwest Jiaotong UniversityChengdu 610031China

Aiming at the problem that aerodynamic uplift forces of the pantograph running in the knuckle-downstream and knuckle-upstream conditions are inconsistent,and their magnitudes do not satisfy the corresponding standard, the aerodynamic uplift forces of pantographs with baffles are numerically investigated, and an optimization method to determine the baffle angle is proposed. First, the error between the aerodynamic resistances of the pantograph obtained by numerical simulation and wind tunnel test is less than 5%, which indicates the accuracy of the numerical simulation method. Second, the original pantograph and pantographs equipped with three different baffles are numerically simulated to obtain the aerodynamic forces and moments of the pantograph *** different angles for the baffles are-17°, 0° and 17°.Then the multibody simulation is used to calculate the aerodynamic uplift force of the pantograph, and the optimal range for the baffle angle is determined. Results show that the lift force of the baffle increases with the increment of the angle in the knuckle-downstream condition, whereas the lift force of the baffle decreases with the increment of the angle in the knuckle-upstream condition. According to the results of the aerodynamic uplift force, the optimal angle of the baffle is determined to be 4.75° when the running speed is 350 km/h, and pantograph–catenary contact forces are 128.89 N and 129.15 N under the knuckledownstream and knuckle-upstream operating conditions,respectively, which are almost equal and both meet the requirements of the standard EN50367:2012.

关键词： High-speed pantograph Aerodynamic uplift force Baffle Numerical simulation multibody simulation

simulation of wheel and rail profile wear:a review of numerical models

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Railway Engineering Science 2022年第4期30卷 403-436页

作者： N.Bosso M.Magelli N.Zampieri Department of Mechanical and Aerospace Engineering Politecnico Di TorinoC.so Duca degli Abruzzi 2410129 TurinItaly

The development of numerical models able to compute the wheel and rail profile wear is essential to improve the scheduling of maintenance operations required to restore the original profile *** work surveys the main numerical models in the literature for the evaluation of the uniform wear of wheel and rail *** standard structure of these tools includes a multibody simulation of the wheel-track coupled dynamics and a wear module implementing an experimental wear ***,the models are classified according to the strategy adopted for the worn profile update,ranging from models performing a single computation to models based on an online communication between the dynamic and wear ***,the most common strategy nowadays relies on an iteration of dynamic simulations in which the profiles are left unchanged,with co-simulation techniques often adopted to increase the computational *** is still needed to improve the accuracy of the current *** experimental campaigns should be carried out to obtain refined wear coefficients and models,while strategies for the evaluation of both longitudinal and transversal wear,also considering the effects of tread braking,should be implemented to obtain accurate damage models.

关键词： Wear Wheel and rail profiles Wheel-rail contact Railway vehicle dynamics multibody simulation Co-simulation

Analysis of positioning of wayside charging stations for hybrid locomotive consists in heavy haul train operations

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Railway Engineering Science 2021年第3期29卷 285-298页

作者： Shah Ahmad Maksym Spiryagin Colin Cole Qing Wu Peter Wolfs Chris Bosomworth Centre for Railway Engineering Central Queensland UniversityRockhamptonQLDAustralia

Hybrid locomotive concepts have been considered as a step towards converting the railway industry into a green transport *** of the challenges in integrating a hybrid locomotive in the train consist is that the battery pack in the locomotive needs to be recharged during a long-haul trip which requires stopping of the train.A typical battery pack requires about 1 h to recharge which is *** the improvement in the charging system,it is now possible that the same capacity battery pack could be recharged in 10–12 min which can be a competitive option for the railway *** paper proposes a method based on simulation to evaluate the positioning of charging stations on a train network.A typical example of a heavy haul train operation hauled by diesel-electric and hybrid locomotives is used to demonstrate the method by using simulation *** result of the simulation study show that the method developed in this paper can be used to evaluate the state of charge(SoC)status of a hybrid locomotive along the *** is also shown that the SoC status obtained by the simulation method can be further used to assess the positions of charging stations along the track at the design stage.

关键词： Hybrid locomotive Wayside charging station Co-simulation multibody simulation

Rail RCF damage quantification and comparison for different damage models

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Railway Engineering Science 2022年第1期30卷 23-40页

作者： Visakh V.Krishna Saeed Hossein-Nia Carlos Casanueva Sebastian Stichel Gerald Trummer Klaus Six Department of Engineering Mechanics KTH Royal Institute of TechnologyStockholmSweden Virtual Vehicle Research GmbH GrazAustria

There are several fatigue-based approaches that estimate the evolution of rolling contact fatigue(RCF) on rails over time and built to be used in tandem with multibody simulations of vehicle dynamics. However, most of the models are not directly comparable with each other since they are based on different physical models even though they shall predict the same RCF damage at the *** article studies different approaches to quantifying RCF and puts forward a measure for the degree of agreement between them. The methodological framework studies various steps in the RCF quantification procedure within the context of one another, identifies the ‘primary quantification step’ in each approach and compares results of the fatigue analyses. In addition to this, two quantities—‘similarity’ and ‘correlation’—have been put forward to give an indication of mutual agreement between *** widely used surface-based and sub-surface-based fatigue quantification approaches with varying complexities have been studied. Different operational cases corresponding to a metro vehicle operation in Austria have been considered for this study. Results showed that the best possible quantity to compare is the normalized damage increment per loading cycle coming from different approaches. Amongst the methods studied, approaches that included the load distribution step on the contact patch showed higher similarity and correlation in their *** the different approaches might qualitatively agree on whether contact cases are ‘damaging’ due to RCF, they might not quantitatively correlate with the trends observed for damage increment values.

关键词： Rolling contact fatigue Rail surface damage Wedge model KTH model Surface fatigue index multibody simulation Track-friendliness