Time-Frequency Analysis.

This paper presents a framework to investigate the dynamics of overall vehicle-track systems with emphasis on theoretical modelling, numerical simulation and experimental validation. A three-dimensional vehicle-track coupled dynamics model is developed in which a typical railway passenger vehicle is modelled as a 35-degree-of-freedom multi-body system. A traditional ballasted track is modelled as two parallel continuous beams supported by a discrete-elastic foundation of three layers with sleepers and ballasts included. The non-ballasted slab track is modelled as two parallel continuous beams supported by a series of elastic rectangle plates on a viscoelastic foundation. The vehicle subsystem and the track subsystem are coupled through a wheel-rail spatial coupling model that considers rail vibrations in vertical, lateral and torsional directions. Random track irregularities expressed by track spectra are considered as system excitations by means of a time-frequency transformation technique. A fast explicit integration method is applied to solve the large nonlinear equations of motion of the system in the time domain. A computer program named TTISIM is developed to predict the vertical and lateral dynamic responses of the vehicle-track coupled system. The theoretical model is validated by full-scale field experiments, including the speed-up test on the Beijing-Qinhuangdao line and the high-speed running test on the Qinhuangdao-Shenyang line. Differences in the dynamic responses analysed by the vehicle-track coupled dynamics and by the classical vehicle dynamics are ascertained in the case of vehicles passing through curved tracks.

https://www.tandfonline.com/doi/pdf/10.1080/00423110802621561

Fundamentals of vehicle–track coupled dynamics

Flywheel Energy Storage System (FESS) is an electromechanical energy storage system which can exchange electrical power with the electric network. It consists of an electrical machine, back-to-back converter, DC link capacitor and a massive disk. Unlike other storage systems such as the Battery Energy Storage System (BESS), FESS is an environmentally-friendly short- or medium-term energy storage system, which has the capability of numerous charge and discharge cycles. These characteristics make the FESS a suitable choice for different applications in the power system such as power quality improvement, power smoothing, renewable energies integration support, stability improvement, etc. This paper presents an overview on the structures and applications of FESS in power system and Microgrid (MG) and also challenges, problems and future works discussed. It can be a driver for development of FESS applications and also recommends suggestions to use its advantages in other areas. Investigation of different studies shows that FESS, as a developing technology, can play an effective role in the operation of the present and future power system and MG.

Review of Flywheel Energy Storage Systems structures and applications in power systems and microgrids

Poly (ionic liquid)s attracted enormous attention as adsorbents for the CO2 separation from natural gas. Hence, in this work poly (1-butyl-3-vinylimidazolium bromide), P[VBIm][Br], poly (1-butyl-3-vinylimidazolium thiocyanate), P[VBIm][SCN], and poly (1-butyl-3-vinylimidazolium tetrafluoroborate), P[VBIm][BF4] were synthesized and evaluated their CO2 adsorption performance. The synthesized poly(ionic liquid)s were characterized by 1H NMR, FT-IR spectroscopy, and differential scanning calorimetery (DSC) analysis. The CO2 adsorption was studied at various temperatures and pressures by quartz crystal microbalance (QCM) and experimental data were correlated by a model of dual-mode. The Henry and Langmuir contributions in CO2 adsorption were evaluated. The obtained thermodynamics and kinetics parameters of CO2 adsorption reveal that CO2 adsorption has an exothermic and physisorption nature. Also, density functional theory (DFT) computations were done in order to assess interactions between poly(ionic liquid)s with CO2 gas. DFT computations corroborated that interaction of P[VBIm][SCN] with CO2 is stronger than those of other poly(ionic liquid)s.

经Co

Suspension components play key roles in the running behaviour of rail vehicles, and therefore, mathematical models of suspension components are essential ingredients of railway vehicle multi-body models. The aims of this paper are to review existing models for railway vehicle suspension components and their use for railway vehicle dynamics multi-body simulations, to describe how model parameters can be defined and to discuss the required level of detail of component models in view of the accuracy expected from the overall simulation model. This paper also addresses track models in use for railway vehicle dynamics simulations, recognising their relevance as an indispensable component of the system simulation model. Finally, this paper reviews methods presently in use for the checking and validation of the simulation model.

Modelling of suspension components in a rail vehicle dynamics context

A dynamic model for the vertical interaction of the rail track and wagon system

Significant developments in longitudinal train simulation and an overview of the approaches to train models and modelling vehicle force inputs are firstly presented. The most important modelling task, that of the wagon connection, consisting of energy absorption devices such as draft gears and buffers, draw gear stiffness, coupler slack and structural stiffness is then presented. Detailed attention is given to the modelling approaches for friction wedge damped and polymer draft gears. A significant issue in longitudinal train dynamics is the modelling and calculation of the input forces – the co-dimensional problem. The need to push traction performances higher has led to research and improvement in the accuracy of traction modelling which is discussed. A co-simulation method that combines longitudinal train simulation, locomotive traction control and locomotive vehicle dynamics is presented. The modelling of other forces, braking propulsion resistance, curve drag and grade forces are also discuss...

Modelling, simulation and applications of longitudinal train dynamics

A thorough understanding of the issues that affect dynamic performance, as well as more inventive methods for controlling rail vehicle dynamics, is needed to meet the demands for safer rail vehicles with higher speed and loads. Design and Simulation of Rail Vehicles examines the field of rail vehicle design, maintenance, and modification, as well as performance issues related to these types of vehicles. This text analyzes rail vehicle design issues and dynamic responses, describes the design and features of rail vehicles, and introduces methods that address the operational conditions of this complex system. Progresses from Basic Concepts and Terminology to Detailed Explanations and Techniques. Focused on both non-powered and powered rail vehicles—freight and passenger rolling stock, locomotives, and self-powered vehicles used for public transport—this book introduces the problems involved in designing and modeling all types of rail vehicles. It explores the applications of vehicle dynamics, train operations, and track infrastructure maintenance. It introduces the fundamentals of locomotive design, multibody dynamics, and longitudinal train dynamics, and discusses co-simulation techniques. It also highlights recent advances in rail vehicle design, and contains applicable standards and acceptance tests from around the world. Design and Simulation of Rail Vehicles serves as an introductory text for graduate or senior undergraduate students, and as a reference for practicing engineers and researchers investigating performance issues related to these types of vehicles.

Design and Simulation of Rail Vehicles

Three types of wagon connection coupling systems are evaluated in a train simulation model consisting of 107 vehicles. The three wagon connection coupling systems are auto-couplers with standard draft gears, auto-couplers with draft gears with wedge unlocking features, and the traditional drawhook buffer system. The train is made up of 103 wagons and 4 locomotives. The locomotives are placed in groups of two at the head and mid-train positions. Dynamic response and fatigue damage is compared for a control disturbance on a crest and on a flat track section. The effect of coupling-free travel (slack) is also investigated.

Yan Quan Sun

Papers

A dynamic model for the vertical interaction of the rail track and wagon system

Modelling, simulation and applications of longitudinal train dynamics

Design and Simulation of Rail Vehicles

Simulated comparisons of wagon coupler systems in heavy haul trains

Wagon–track modelling and parametric study on rail corrugation initiation due to wheel stick-slip process on curved track