The Experts below are selected from a list of 324 Experts worldwide ranked by ideXlab platform
Zhigang Liu - One of the best experts on this subject based on the ideXlab platform.
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A Siamese Network-Based Non-Contact Measurement Method for Railway Catenary Uplift Trained in a Free Vibration Test.
Sensors (Basel Switzerland), 2020Co-Authors: Fuchuan Duan, Zhigang Liu, Donghai Zhai, Anders RønnquistAbstract:The vibration of the Catenary that is initiated by the passing pantograph has a direct influence on the pantograph–Catenary contact performance. Monitoring the dynamic uplift of the Catenary can help inspectors to evaluate the railway operation conditions and investigate the mechanism of pantograph–Catenary interaction further. In this paper, a non-contact measurement method based on the deep leaning method is proposed to monitor the real-time vibration of the Catenary. The field test for the Catenary free vibration is designed to validate the method’s performance. The measurement method is developed based on the fully convolutional Siamese neural network, and the contact wire is taken as the tracking target. To reduce the recognition errors caused by the changes in the shape and grayscale of the moving contact wire in images, the class-agnostic binary segmentation mask is adopted. A developed down-sampling block is used in the neural network to reduce the image feature loss, which effectively enhances the recognition effect for the Catenary vibration under variable lighting conditions. To validate the performance of the proposed measurement method, a series of field tests of Catenary free vibration were conducted under various lighting conditions and different excitations, and the recognition results were compared with traditional target tracking methods. The results show that the proposed method performs well for Catenary vibration identification in the field test. Additionally, the uplift data extracted from the identified images agree with the numerical results, and also help to further investigate the wave propagation and damping characteristics in the Catenary structure.
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Research on Ice-Melting Technology of Urban Rail Transit Catenary Based on Energy Cycle
Lecture Notes in Electrical Engineering, 2018Co-Authors: Liu Jian, Gang Zhang, Fengjie Hao, Zhigang Liu, Bai XibinAbstract:When the train is running, if the Catenary is heavily covered by ice, there will be arcs between the pantograph and the Catenary, resulting in the train to be powered abnormally, even causing major accidents such as Catenary breaks and pantograph damage. This paper proposes an ice-melting scheme based on energy cycle which is formed between the medium voltage grid and the icing Catenary. The current of the Catenary is controlled over the ice-melting current, which produces Joule heat to melt the ice. This paper analyzes the working principle and control strategy of the ice-melting system, calculates the ice-melting current, verifies the effectiveness of the control method and realizes the expected energy cycle by simulation.
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Advances of research on high-speed railway Catenary
Journal of Modern Transportation, 2017Co-Authors: Zhigang Liu, Yang Song, Ye Han, Hongrui Wang, Jing Zhang, Zhiwei HanAbstract:The interaction between the Catenary and pantograph is one of the most crucial factors that determine the train operation in high-speed railway. The bad state of Catenary is able to directly influence the power supply safety of traction power system. In this paper, four aspects on the Catenary research of high-speed railway are reviewed in detail, namely the solution methods for Catenary equilibrium state, the dynamic modeling methods of Catenary, non-contact detection methods of Catenary, and the static and dynamic evaluation methods of Catenary. In addition, their recent advances are described. For the low solution accuracy of the initial equilibrium state of Catenary, the structure finding method with multi-objective constraint and nonlinear finite element procedure are introduced to solve the problem. For the Catenary’s dynamic modeling, considering the influence of environmental wind on the Catenary, environmental wind simulations and wind tunnel tests are used to obtain the aerodynamic coefficients and build the wind field along the Catenary for analysis of its wind vibration characteristics. In order to improve the detection accuracy of non-contact detection for the Catenary, the deep learning theory and real-time detection algorithms should be adopted in the future. In view of the lack of dynamic assessment method for the Catenary, the modern spectrum evaluation, time–frequency analysis, big data technology and their combinations will be the important means for future Catenary evaluation.
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Detection and Estimation Research of High-speed Railway Catenary
Advances in High-speed Rail Technology, 2017Co-Authors: Zhigang LiuAbstract:This book describes the wave characteristics of contact lines taking wind into consideration and discusses new methods for detecting Catenary geometry, pantograph slide fault, and Catenary support system faults. It also introduces wire-irregularity detection methods for Catenary estimation, and discusses modern spectrum estimation tools for Catenary. It is organized in three parts: the first discusses statistical characteristics of pantograph-Catenary data, such as stationarity, periodicity, correlation, high-order statistical properties and wave characteristics of contact lines, which are the basis of pantograph-Catenary relationship analysis. The second part includes geometry parameter detection and support-system fault detection in Catenary, as well as slide-fault detection in pantographs, and presents some new detection algorithms and plans. The final part addresses Catenary estimation, including detection of contact-line wire irregularities and estimation of Catenary based on spectrum, and presents detection methods for contact-line irregularity and modern spectrum estimation tools for Catenary
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Statistical Characteristics of Pantograph-Catenary Contact Pressure
Detection and Estimation Research of High-speed Railway Catenary, 2016Co-Authors: Zhigang LiuAbstract:In order to grasp the basic characteristics of pantograph-Catenary interaction and study the influence of parameters of the pantograph and the Catenary on each other, the analysis of pantograph-Catenary dynamic coupling is very important. The statistical characteristics of pantograph-Catenary data are the basis of pantograph-Catenary relationship analysis.
Anders Rønnquist - One of the best experts on this subject based on the ideXlab platform.
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A Siamese Network-Based Non-Contact Measurement Method for Railway Catenary Uplift Trained in a Free Vibration Test.
Sensors (Basel Switzerland), 2020Co-Authors: Fuchuan Duan, Zhigang Liu, Donghai Zhai, Anders RønnquistAbstract:The vibration of the Catenary that is initiated by the passing pantograph has a direct influence on the pantograph–Catenary contact performance. Monitoring the dynamic uplift of the Catenary can help inspectors to evaluate the railway operation conditions and investigate the mechanism of pantograph–Catenary interaction further. In this paper, a non-contact measurement method based on the deep leaning method is proposed to monitor the real-time vibration of the Catenary. The field test for the Catenary free vibration is designed to validate the method’s performance. The measurement method is developed based on the fully convolutional Siamese neural network, and the contact wire is taken as the tracking target. To reduce the recognition errors caused by the changes in the shape and grayscale of the moving contact wire in images, the class-agnostic binary segmentation mask is adopted. A developed down-sampling block is used in the neural network to reduce the image feature loss, which effectively enhances the recognition effect for the Catenary vibration under variable lighting conditions. To validate the performance of the proposed measurement method, a series of field tests of Catenary free vibration were conducted under various lighting conditions and different excitations, and the recognition results were compared with traditional target tracking methods. The results show that the proposed method performs well for Catenary vibration identification in the field test. Additionally, the uplift data extracted from the identified images agree with the numerical results, and also help to further investigate the wave propagation and damping characteristics in the Catenary structure.
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Development of an index for quantification of structural dynamic response in a railway Catenary section
Engineering Structures, 2020Co-Authors: Petter Nåvik, Stefano Derosa, Anders RønnquistAbstract:Abstract In an attempt to quantify the amount of the dynamic reaction in a railway Catenary system due to the dynamic action created by the interaction with the pantograph of the train, a Catenary dynamic index (CDI) is developed. The index is intended for comparing structural dynamic responses in different situations. Comparisons between positions in a Catenary to evaluate the design or comparisons between passages to evaluate train passages and automatically tell if a pantograph is faulty. This index can be a helpful tool for infrastructure managers, designers and academics to evaluate both measured and simulated data as well as controlling trains in the rail network. The CDI is computed for a given position on the Catenary using the response before and after train passage. This involves both the pre-passage interaction dominated phase and the Catenary free vibration phase of the Catenary response. This approach is significantly different from using the pantograph contact forces since the contact forces only gives one value per contact point, while the index describes a single point over a period of time, both along the wire. More important, this method can assess a great variety of train passages, in stark contrast to the contact force measurements, which describes the behaviour often from one single control train with very limited number of passages a year (in Norway no more than two times). Therefore, the CDI quantitatively describes the energy content in a railway Catenary for a whole train passage. This paper presents the method and results when using the CDI on field measurements. The results show that the Catenary dynamic index can describe important variations the dynamic response of a Catenary system and that it changes with changing boundary conditions. During a short monitoring period the method identified successfully two real outliers, important for the infrastructure owner, and showing a suitability for structural health monitoring.
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Dynamic comparison of a railway Catenary section upgrade by field measurement assessments
Procedia Engineering, 2017Co-Authors: Petter Nåvik, Anders RønnquistAbstract:Abstract The pantograph-Catenary interaction is crucial for running trains on electrical railway lines. The coupled dynamic problem of an in space stationary system, the Catenary system, and a system in motion, the pantograph, is dependent on the behaviour of both combined as well as individually. Different Catenary systems exhibit different behaviour. This paper evaluates a Catenary system upgrade by dynamic assessment. Existing railway Catenary sections are upgraded or replaced due to wear, but also due to an aim for improved running quality or increased speed on the rail line. Field measurements were conducted on an old Catenary section. This section was then upgraded, and some months later measurements were conducted on the new Catenary section. Thus, field measurements were sampled at the same location twice. Since the measurements were sampled only months apart and that all measurements are recording behaviour under regular train operation, the loading is assumed to be identical. Dynamic assessment of both sections has been done using power spectral densities and histograms. Important differences and similarities in their response can be seen. This study further increases the knowledge regarding the dynamic behaviour of railway Catenary sections when evaluating the impact of the upgrades.
Weihua Zhang - One of the best experts on this subject based on the ideXlab platform.
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Study on Simulation Method of Pantograph-Catenary System Considering Ice Coating
Lecture Notes in Mechanical Engineering, 2020Co-Authors: Yongming Yao, Dong Zou, Jiangwen Wang, Ning Zhou, Weihua ZhangAbstract:The icing problem of Catenary is becoming more and more prominent with the expansion of the distribution range of rail transit lines. Ice coating on Catenary will affect the sliding of pantograph and the power supply quality of train. In serious cases, the phenomenon of arc tension between Catenary and pantograph will also occur, which threatens the normal operation of trains. The equivalent density method and the uniform load method of icing are studied to analyze the icing problem of pantograph-Catenary system. The similarities and differences between the two simulation methods are compared. The pantograph-Catenary dynamics simulation analysis is carried out based on the multi-rigid body model of pantograph. The results show that the icing of Catenary will affect the current collecting quality of pantograph-Catenary system. The difference between the two models in calculating the dynamic response of pantograph-Catenary system after icing becomes obvious with the increase of icing thickness, and the mechanism of the difference is analyzed.
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Review of pantograph and Catenary interaction
Frontiers of Mechanical Engineering, 2018Co-Authors: Weihua Zhang, Dong Zou, Ning Zhou, Mengying Tan, Guiming MeiAbstract:The application of electrified railway directly promotes relevant studies on pantograph-Catenary interaction. With the increase of train running speed, the operating conditions for pantograph and Catenary have become increasingly complex. This paper reviews the related achievements contributed by groups and institutions around the world. This article specifically focuses on three aspects: The dynamic characteristics of the pantograph and Catenary components, the systems’ dynamic properties, and the environmental influences on the pantograph-Catenary interaction. In accordance with the existing studies, future research may prioritize the task of identifying the mechanism of contact force variation. This kind of study can be carried out by simplifying the pantograph-Catenary interaction into a moving load problem and utilizing the theory of matching mechanical impedance. In addition, developing a computational platform that accommodates environmental interferences and multi-field coupling effects is necessary in order to further explore applications based on fundamental studies.
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static form finding analysis of a railway Catenary using a dynamic equilibrium method based on flexible multibody system formulation with absolute nodal coordinates and controls
Multibody System Dynamics, 2017Co-Authors: Weihua Zhang, Guiming Mei, Chun Yang, J Zhang, N Zhou, Gexue RenAbstract:This paper proposes a dynamic equilibrium method for finding the initial equilibrium configuration of a railway Catenary. In the proposed method, the Catenary composed of flexible wires is modeled using two-node cable elements with absolute nodal coordinates based on a flexible multibody system formulation. Dynamic conditions that characterize the initial equilibrium configuration of the Catenary are given and addressed as control processes in the form-finding procedure. The key feature of the proposed method is that the Catenary configuration is continually evolved by dynamic simulation until characterization conditions are attained and an equivalent configuration of the centenary at static equilibrium is thus computed. It is validated using two examples and applied to the form-finding analysis of a two dimensional simple railway Catenary. The obtained results are analyzed and discussed. It is general and can be applied to catenaries with complex configurations.
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Friction-Induced, Self-Excited Vibration of a Pantograph-Catenary System
Journal of Vibration and Acoustics, 2013Co-Authors: W.j. Qian, G X Chen, Weihua Zhang, Huajiang Ouyang, Zhongrong ZhouAbstract:A dynamic model of a pantograph-Catenary system is established. In the model, motion of the pantograph is coupled with that of the Catenary by friction. Stability of the pantograph-Catenary system is studied using the finite element complex eigenvalue method. Numerical results show that there is a strong propensity of self-excited vibration of the pantograph-Catenary system when the friction coefficient is greater than 0.1. The dynamic transient analysis results show that the self-excited vibration of the pantographCatenary system can affect the contact condition between the pantograph and Catenary. If the amplitude of the self-excited vibration is strong enough, the contact may even get lost. Parameter sensitivity analysis shows that the coefficient of friction, static lift force, pan-head suspension spring stiffness, tension of contact wire, and the spatial location of pantograph have important influences on the friction-induced, self-excited vibration of the pantograph-Catenary system. Bringing the friction coefficient below a certain level and choosing a suitable static lift force can suppress or eliminate the contact loss between the pantograph and Catenary. [DOI: 10.1115/1.4023999]
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Pantograph and Catenary system with double pantographs for high-speed trains at 350 km/h or higher
Journal of Modern Transportation, 2011Co-Authors: Weihua Zhang, Ning Zhou, Guiming Mei, Dongli SongAbstract:The paper is aimed at developing an optimized design of the pantograph and Catenary system with double pantographs at a speed of 350 km/h for the Wuhan-Guangzhou high-speed railway. First, the pantograph and Catenary system for the Beijing-Tianjin high-speed railway was analyzed to verify whether its design objective could be fulfilled. It shows that the system is not able to satisfy the requirement of a sustainable running speed of 350 km/h. Then a new scheme for the pantograph and Catenary system is proposed through optimization and renovation of the structure and parameters of the pantograph and Catenary system, including the suspension type of the Catenary, tension of the contact wire, and space between two pantographs. Finally, the dynamic performance of the new system was verified by simulation and line testing. The results show that the new scheme of the pantograph and Catenary system for the Wuhan-Guangzhou high-speed railway is acceptable, in which the steady contact between the rear pantograph and the Catenary at the space of 200 m can be maintained to ensure the current-collection quality. A current collection with double pantographs at a speed of 350 km/h or higher can be achieved.
Ahmed A. Shabana - One of the best experts on this subject based on the ideXlab platform.
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Three-Dimensional Large Deformation Analysis of the Multibody Pantograph/Catenary Systems
Nonlinear Dynamics, 2005Co-Authors: Jong-hwi Seo, Hiroyuki Sugiyama, Ahmed A. ShabanaAbstract:To accurately model the nonlinear behavior of the pantograph/Catenary systems, it is necessary to take into consideration the effect of the large deformation of the Catenary and its interaction with the nonlinear pantograph system dynamics. The large deformation of the Catenary is modeled in this investigation using the three-dimensional finite element absolute nodal coordinate formulation. To model the interaction between the pantograph and the Catenary, a sliding joint that allows for the motion of the pan-head on the Catenary cable is formulated. To this end, a non-generalized arc-length parameter is introduced in order to be able to accurately predict the location of the point of contact between the pan-head and the Catenary. The resulting system of differential and algebraic equations formulated in terms of reference coordinates, finite element absolute nodal coordinates, and non-generalized arc-length and contact surface parameters are solved using computational multibody system algorithms. A detailed three-dimensional multibody railroad vehicle model is developed to demonstrate the use of the formulation presented in this paper. In this model, the interaction between the wheel and the rail is considered. For future research, a method is proposed to deal with the problem of the loss of contact between the pan-head and the Catenary cable.
Jong-hwi Seo - One of the best experts on this subject based on the ideXlab platform.
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Dynamic analysis of a pantograph–Catenary system using absolute nodal coordinates
Vehicle System Dynamics, 2006Co-Authors: Jong-hwi Seo, Ilho Jung, Taewon Park, Seok-won Kim, Jin-yong Mok, Young-guk Kim, Jangbom ChaiAbstract:The dynamic interaction between the Catenary and the pantographs of high-speed trains is a very important factor that affects the stable electric power supply. In order to design a reliable current collection system, a multibody simulation model can provide an efficient and economical method to analyze the dynamic behavior of the Catenary and pantograph. In this article, a dynamic analysis method for a pantograph–Catenary system for a high-speed train is presented, employing absolute nodal coordinates and rigid body reference coordinates. The highly flexible Catenary is modeled using a nonlinear continuous beam element, which is based on an absolute nodal coordinate formulation. The pantograph is modeled as a rigid multibody system. The analysis results are compared with experimental data obtained from a running high-speed train. In addition, using a derived system equation of motion, the calculation method for the dynamic stress in the Catenary conductor is presented. This study may have significance in ...
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Three-Dimensional Large Deformation Analysis of the Multibody Pantograph/Catenary Systems
Nonlinear Dynamics, 2005Co-Authors: Jong-hwi Seo, Hiroyuki Sugiyama, Ahmed A. ShabanaAbstract:To accurately model the nonlinear behavior of the pantograph/Catenary systems, it is necessary to take into consideration the effect of the large deformation of the Catenary and its interaction with the nonlinear pantograph system dynamics. The large deformation of the Catenary is modeled in this investigation using the three-dimensional finite element absolute nodal coordinate formulation. To model the interaction between the pantograph and the Catenary, a sliding joint that allows for the motion of the pan-head on the Catenary cable is formulated. To this end, a non-generalized arc-length parameter is introduced in order to be able to accurately predict the location of the point of contact between the pan-head and the Catenary. The resulting system of differential and algebraic equations formulated in terms of reference coordinates, finite element absolute nodal coordinates, and non-generalized arc-length and contact surface parameters are solved using computational multibody system algorithms. A detailed three-dimensional multibody railroad vehicle model is developed to demonstrate the use of the formulation presented in this paper. In this model, the interaction between the wheel and the rail is considered. For future research, a method is proposed to deal with the problem of the loss of contact between the pan-head and the Catenary cable.
