Explore the vast range of titles available.

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.

Catenary action plays crucial role in resisting the applied vertical load at large deformations stage in reinforced concrete (RC) structures. This paper aims to predict the catenary action capacity of RC beam-column substructures by utilizing the distinctive properties of gene expression programming (GEP). The input parameters selected for the modelling are: double-beam span-to-depth ratio, relative axial restraints stiffness, relative rotational restraints stiffness, bottom and top longitudinal reinforcement ratios, and yield strength of longitudinal rebars. A comprehensive and reliable database was collated from internationally published research articles to develop and verify the model. The GEP-based model was assessed by comparing its performance with regression based model. Various statistical indicators and external validation criteria suggested in literature proved that the model is accurate and possess high prediction and generalization capacity. Sensitivity analysis was carried out to show the contributions of the input parameters, while parametric analysis was performed to show that the proposed model is not merely a combination of the input parameters but can accurately represent the given physical system. The proposed formulation from GEP is found to be simple, robust, and easy to utilize for pre-design purposes.

The concept of catenary has been recently extended to the sphere and the hyperbolic plane by the second author (López, arXiv:2208.13694 ). In this work, we define catenaries on any Riemannian surface. A catenary on a surface is a critical point of the potential functional, where we calculate the potential with the intrinsic distance to a fixed reference geodesic. Adopting semi-geodesic coordinates around the reference geodesic, we characterize catenaries using their curvature. Finally, after revisiting the space-form catenaries, we consider surfaces of revolution (where a Clairaut relation is established), ruled surfaces, and the Grušin plane.

Increasing the speed of a pantograph deteriorates its aerodynamic performance and aggravates the problem of flow-induced vibration, which is not conducive to the stability of the pantograph – catenary system (PCS). Currently, commercial high-speed trains operate at speeds exceeding 350 km/h, with line test speeds exceeding 450 km/h, making the impact of airflow on pantograph dynamics increasingly significant. Therefore, a simulation study on the bidirectional coupling between pantograph aerodynamics and structural dynamics is urgently needed. This study proposes a bidirectional coupling method for the pantograph based on overset grids. The user-defined functions (UDF) in Fluent enable real-time data exchange between aerodynamic forces and structural displacements. The flow field was modelled using the Shear Stress Transport k–ω turbulence model and Reynolds-averaged Navier – Stokes equations, and the dynamics is computed by Newmark-Beta solving the differential equations. It was found that the calculation method in this study was reliable and efficient. The motion of the pantograph assembly in the flow field will change the airflow mode, thus affecting the aerodynamic characteristics of the assembly, and the high-frequency and stochastic aerodynamic excitation will lead to an increase in vibration of the pantograph assembly, especially at the contact strip. For example, when the pantograph operated in the knuckle-upstream direction at 450 km/h, it exhibited poor PCS interaction, with a mean contact force of 50 N, a standard deviation of 36 N, and an overall offline rate of 7%. This study introduced a novel approach to pantograph fluid – structure coupling, offering valuable insights for predicting high-speed pantograph performance and evaluating PCS interactions.

The current carrying capacity of pantograph-catenary will also change dynamically with the continuous change of train speed. The influence of internal and external parameters such as running speed, current, pressure and vibration must be fully considered. Based on this, this paper first analyses the action relationship between CRH pantograph-catenary under fluctuating load, then studies the measurement of current carrying friction between CRH pantograph-catenary under fluctuating load, and finally gives the MATLAB simulation of current carrying friction between pantograph-catenary under fluctuating load.

As the unique power entrance, the pantograph–catenary electrical contact system maintains the efficiency and reliability of power transmission for the high-speed train. Along with the fast development of high-speed railways all over the world, some commercialized lines are built for covering the remote places under harsh environment, especially in China; these environmental elements including wind, sand, rain, thunder, ice and snow need to be considered during the design of the pantograph–catenary system. The pantograph–catenary system includes the pantograph, the contact wire and the interface—pantograph slide. As the key component, this pantograph slide plays a critical role in reliable power transmission under dynamic condition. The fundamental material characteristics of the pantograph slide and contact wire such as electrical conductivity, impact resistance, wear resistance, etc., directly determine the sliding electrical contact performance of the pantograph–catenary system; meanwhile, different detection methods of the pantograph–catenary system are crucial for the reliability of service and maintenance. In addition, the challenges brought from extreme operational conditions are discussed, taking the Sichuan–Tibet Railway currently under construction as a special example with the high-altitude climate. The outlook for developing the ultra-high-speed train equipped with the novel pantograph–catenary system which can address the harsher operational environment is also involved. This paper has provided a comprehensive review of the high-speed railway pantograph–catenary systems, including its progress, challenges, outlooks in the history and future.

In this paper, the nonlinear bending of the slender flexible cable connected to floating offshore energy platforms is considered. The aim is to find accurate values for the bending stress in the catenaries that lead to fatigue and short lifetime. A new approach called Extended Stiffened Catenary Theory (ESCT) is described and outlined, which accurately predicts the bending stresses such that they can be validated by high-fidelity FEM software, e.g., ABAQUS 2024. It is found that some widely used software, such as Orcaflex 11.4, underestimates these bending stresses. Although the Orcaflex uses built-in FEM software to analyse the stresses, there are substantial differences between the results. Since the stresses are underestimated, it can lead to a wrongly estimated higher fatigue lifetime. Therefore, a critical review of stress analysis in Orcaflex is carried out to find the origins of such underestimation. It is shown that the explicit integration of equations of motion in Orcaflex is the reason for such underestimation, even in static analysis. The ABAQUS can predict accurately because of implicit (standard) integration. It is concluded that using this ESCT allows us to estimate a more realistic and reliable stress, thereby leading to a realistic lifetime for catenary umbilicals and cables for floating platforms.

The present study investigates the effect of moorings on hybrid floating breakwaters of different configurations based on potential flow theory. The mooring analysis is performed for the regular wave incidence for five different shapes of hybrid floating breakwaters, namely, rectangular, box, H, Π, and trapezoidal, integrated with a single J-shaped oscillating water column (OWC). The mooring lines are considered to be nonlinear catenary sections that are analysed for open mooring and cross mooring configuration. The hydrodynamic analysis is performed using Ansys-AQWA and the effectiveness of the moorings is evaluated in terms of the mooring line tension and the floating structure’s motion response, and comparisons are made for the influence of different mooring configurations and the implications of changing the design of the hybrid floating breakwater. The regular gravity wave frequency range is taken into consideration and the hydrodynamic properties are reported for the entire range of regular wave frequencies. Additionally, for a few chosen wave frequencies the analysis of structural forces and moment is performed for long and short waves. The study suggests that a hydrodynamically stable hybrid floating structure integrated with an oscillating water column can provide good and effective wave energy conversion and wave attenuation. Thus, with the help of the findings of the present study, the researchers will be able to examine the stability of hybrid floating breakwater structures under the action of regular waves with normal incidence.

Zhuanyao dwellings faced significant seismic risks in rural regions of China. Therefore, a shaking-table test was performed to explore the seismic performance of Zhuanyaos and validate the finite-element simulation results. The results showed that the damage to the pier and roof levels of Zhuanyaos was more severe after earthquakes, resulting in a noteworthy increase in the displacement responses of these two levels compared to that of the vault level. The damage to the front structure (Yaolian) and mid-pier of the Zhuanyao were more severe than the damage to the back wall and side pier, respectively, which caused a significant reduction in acceleration responses of Yaolian and mid-pier. Following the crack development, dynamic response, and field investigation, three typical collapse modes of Zhuanyaos were presented. Subsequently, the parametric analysis was conducted using a verified finite-element simulation method. The results show that using the catenary arch can reduce earthquake damage in Zhuanyaos. Increasing the width of the middle pier can improve the seismic performance of Zhuanyaos to a certain extent; however, it may exacerbate local damage to the structure. Besides, the high seismic vulnerability of Zhuanyaos stemming from an increasing thickness of overlying soil cannot be ignored.

To establish a theoretical foundation for assessing the dynamic performance of high-speed train catenary systems in wind-prone regions, this study develops a coupled pantograph–catenary model using ANSYS(2022R1) APDL. The dynamic responses of conventional high-speed pantographs traversing both mainline and transition sections are analyzed under varying operational conditions. The key findings reveal that an elevated rated tension in the contact wire and messenger wire reduces the pantograph lift in wind areas with no crosswind compared to non-wind areas, with an average lift reduction of 8.52% and diminished standard deviation, indicating enhanced system stability. Under a 20 m/s crosswind, both tested pantograph designs maintain contact force and dynamic lift within permissible thresholds, while significant catenary undulations predominantly occur at mid-span locations. Active control strategies preserve the static lift force but induce pantograph flattening under compression, reducing aerodynamic drag and resulting in smaller contact force fluctuations relative to normal-speed sections. In contrast, passive control increases static lift, thereby causing greater fluctuations in contact force compared to baseline conditions. The superior performance of active control is attributed to its avoidance of static lift amplification, which dominates the dynamic response in passive systems.