scholarly journals MODELLING AND ANALYSIS OF AN IRREGULAR RAILWAY TRACK SYSTEM FOR COMPUTATION OF CRITICAL VELOCITY FOR LIMITING VERTICAL ACCELERATION

2018 ◽  
Vol 27 (1) ◽  
pp. 146-154
Author(s):  
Akshay Gupta ◽  
Puja Deka ◽  
Nirmalendu Debnath
Keyword(s):  
Critical Velocity ◽  
Railway Track ◽  
Vertical Acceleration ◽  
Track System

scholarly journals Methodology for studying impulse disturbance from rail joints to the railway vehicle and assessment of the efficiency of the new spring suspension

2018 ◽  
Vol 239 ◽  
pp. 01032
Author(s):  
Viktor Nekhaev ◽  
Viktor Nikolaev ◽  
Evgenii Cheltygmashev
Keyword(s):  
Energy Dissipation ◽  
Comparative Assessment ◽  
Railway Track ◽  
Railway Vehicle ◽  
Vertical Acceleration ◽  
External Disturbances ◽  
Spring Suspension ◽  
Dynamic Forces ◽  
Typical Scheme ◽  
Freight Car

The methodology for studying the impulse disturbance of the railway track joints on the indicators of the dynamic qualities of the railway vehicle has been developed. The dependence of the impulse repetition factor on the energy dissipation level in the system and the speed of the vehicle is obtained. A comparative assessment of the dynamic qualities of a freight car with a typical scheme of spring suspension and a car with suspension based on the principle of compensation of external disturbances is performed. It has been established that the spring suspension of a freight car based on the principle of compensation of external disturbances delivers to it significantly better indicators of dynamic qualities in comparison with car equipped with a new three-piece truck with a typical scheme of springs. Vertical acceleration of the car’s body with a new scheme of vibration protection and dynamic forces in spring suspension is several times less than for a car with a typical three-piece truck structure.

IMPORTANCE OF NONLINEARITY OF TRACK SUPPORT SYSTEM IN MODELING OF RAILWAY TRACK DYNAMICS

2013 ◽  
Vol 13 (01) ◽  
pp. 1350008 ◽  
Author(s):  
J. SADEGHI ◽  
M. FESHARAKI
Keyword(s):  
Support System ◽  
Field Tests ◽  
Field Investigation ◽  
Dynamic Responses ◽  
Railway Track ◽  
Nonlinear Properties ◽  
Railway Tracks ◽  
Track Dynamics ◽  
Track System ◽  
Axle Loads

Attention is drawn to the fact that the recent increase in axle loads, speed and traffic volume in railway tracks, as well as concerns over passengers' riding comfort and safety have resulted in fresh challenges that are needed to be addressed. These challenges can only be successfully tackled with a more accurate modeling of the dynamic behavior of railway tracks. Although a significant amount of research involving mathematical modeling of railway track dynamics has been conducted in the last two decades, the nonlinearity of track support systems has not been given sufficient attention. This paper is concerned with the effect of nonlinearity of the support sub-layers on the dynamic responses of the railway track. To this end, a railway track model that considers the nonlinear properties of the track sub-layers is developed. Then, a field investigation into the dynamic responses of the railway track system under moving trains is conducted. The effect of the nonlinearity properties of the track support system on the track responses is investigated by comparing the results obtained by the numerical model, with or without consideration of track support nonlinearity, with those from the field tests. It is illustrated that consideration of the nonlinear properties of the track support system improves the accuracy of the calculated responses by a factor of three. It is also shown that the train axle loads and track accumulative loading have a significant effect on the nonlinearity of the track support system and, as a result, on the modeling of track responses.

scholarly journals Vertical Dynamic Analysis of Ballastless Tracks on Train-Track- Bridge System

2020 ◽  
Vol 306 ◽  
pp. 02003
Author(s):  
Haoran Xie ◽  
Bin Yan ◽  
Jie Huang
Keyword(s):  
Track Structure ◽  
Vertical Acceleration ◽  
Train Track ◽  
Steel Spring ◽  
Slab Track ◽  
Ballastless Track ◽  
Track System ◽  
Train Speed ◽  
Track Bridge ◽  
Bridge System

In order to investigate the vertical dynamic response characteristics of train-track-bridge system on CWR (Continunously Welded Rail) under dynamic load of train on HSR (High-Speed Railway) bridge. Based on the principle of vehicle train-track-bridge coupling dynamics, taking the 32m simply supported bridge of a section of Zhengzhou-Xuzhou Passenger Dedicated Line as an example, the finite element software ANSYS and the dynamic analysis software SIMPACK are used for co-simulation, and bridge model of the steel spring floating slab track and the CRTSIII ballastless track (China Railway Track System) considering the shock absorbing steel spring, the limit barricade and the contact characteristics of track structure layers are established. On this basis, in order to study the dynamic response laws of the design of ballastless track structure parameters to the system when the train crosses the bridge and provide the basis for the design and construction, by studying the influence of the speed of train on the bridge, the damage of fasteners and the parameters of track structure on the train-track-bridge system, the displacement of rail, vertical vibration acceleration and wheel-rail force response performance are analyzed. Studies have shown that: At the train speed of 40 km/h, the displacement and acceleration of the rail and track slab in the CRTSIII ballastless track are smaller than the floating slab track structure, but the floating slab track structure has better vibration reduction performance for bridges. The acceleration of rail, track slab and bridge increases obviously with the increase of train speed, the rail structure has the largest increasement. Reducing the stiffness of fasteners could decrease the vertical acceleration response of the steel spring floating slab track system, the ability to absorb shock can be enhanceed by reducing the stiffness of the fastener appropriately. Increasing the density of the floating slab can increase the vertical acceleration of the floating slab and the bridge, thereby decreasing the vibration amplitude of the system.

Finite Element Analysis of a Fishplate Rail Joint in Extreme Environment Condition

2020 ◽  
Vol 12 (5) ◽  
Author(s):  
Sunil Kumar Sharma ◽  
Jaesun Lee
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Extreme Environment ◽  
High Rate ◽  
Railway Track ◽  
Element Analysis ◽  
Track System ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

Railways are very efficient mode of transportation. Speed limits of the railways and loads they carry are increasing rapidly. Due to some advantages, the insulated rail joints are still the part of a rail-track system. However, a high rate of failure of joints puts the railway track at risk. Therefore, a detailed study of these joints is required. In this paper, a three-dimensional finite element model of rail-fishplate joint is created using Abaqus - a finite element method-based software. Stresses in fishplate and bolts due to wheel impact are analysed by coupling implicit and explicit methods. It is found that bolts are a critical part of a joint due to stresses and vibrations to which they are subjected. The large number of stresses and vibration can result into loosening of bolts.

Moving element analysis of discretely supported high-speed rail systems

2017 ◽  
Vol 232 (3) ◽  
pp. 783-797 ◽  
Author(s):  
Jian Dai ◽  
Kok Keng Ang ◽  
Minh Thi Tran ◽  
Van Hai Luong ◽  
Dongqi Jiang
Keyword(s):  
High Speed ◽  
Railway Track ◽  
High Speed Train ◽  
Element Analysis ◽  
High Speed Rail ◽  
Mass System ◽  
Rail System ◽  
Rail Systems ◽  
Track System ◽  
The Difference

In this paper, a computational scheme in conjunction with the moving element method has been proposed to investigate the dynamic response of a high-speed rail system in which the discrete sleepers on the subgrade support the railway track. The track foundation is modeled as a beam supported by uniformly spaced discrete spring-damper units. The high-speed train is modeled as a moving sprung-mass system that travels over the track. The effect of the stiffness of the discrete supports, train speed, and railhead roughness on the dynamic behavior of the train–track system has been investigated. As a comparison, the response of a continuously supported high-speed rail system that uses a foundation stiffness equivalent to that of a discretely supported track has been obtained. The difference in results between the “equivalent” continuously supported and the discretely supported high-speed rails has been compared and discussed. In general, the study found that a high-speed train that travels over a discretely supported track produces more severe vibrations than that travels over a continuously supported track of equivalent foundation stiffness.

Mathematical Modeling for Longitudinal Displacement of a Straight Continuously Welded Railway Track and its Numerical Implementation

2011 ◽  
Vol 462-463 ◽  
pp. 801-806 ◽  
Author(s):  
Abreeza Manap
Keyword(s):  
Mathematical Model ◽  
Computer Software ◽  
Railway Track ◽  
Track Length ◽  
Longitudinal Displacement ◽  
Track System ◽  
Displacement Pattern ◽  
Longitudinal Flexibility ◽  
Displacement Patterns ◽  
The Mathematical Model

A mathematical model of the longitudinal flexibility of a continuously welded railway track and the methodology for the analysis of the longitudinal displacement of rails under the effects of passing trains is developed to investigate the longitudinal behavior of rails. The purpose of this analysis is to explore the changes of longitudinal stress distribution in the rails due to mechanical loading applied by a travelling train. A half track system is used to derive the equations required to obtain the magnitude of deflection and force of rails and these values are scaled to produce the displacement pattern using the method of superposition. The mathematical model is translated into MATLAB and validation of the program is verified through comparisons of displacement patterns generated by a computer software LONGIN. Analysis of a straight track due to train braking was performed over a track length of 1000 m. The longitudinal displacement obtained showed that maximum longitudinal displacement occur in the middle of the track at the distance of 570 m which is in direct agreement with the published result.

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