Analysis on the Influence of Rail Pad on Ballasted Railway Track
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Date
2018-07-09
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Addis Ababa University
Abstract
Railway tracks are commonly constructed with resilient elements (rail pads, ballasts etc.) They serve as the primary means of reducing the level of vibration generated through railway operations, key element in the transfer of wheel-rail forces into the track substructure, filter and transfer the dynamic forces from rails and fasteners to the sleepers. Understanding of the mechanistic behaviour of the rail pad is important in the development of improved track components.
The purpose of this thesis is to study the influence of rail pad on the behaviour of ballasted Railway track under dynamic and static loading. By creating models in the finite element program ABAQUS and ANSYS apdl responses to dynamic and static loading is studied respectively, using a 2D model. Beam on discrete support model is selected for the track; the rail and sleeper are best modelled by Euler-Bernoulli beam element. Spring and dashpot is used for the simulation of rail pads and the connection between the sleeper and subgrade ground. At last the models developed are analysed to study the effect of rail pad and speed on track component under different train location and different method of analysis, using the above Finite Element Packages.
Even though, the main use of Rail pad is to filter the dynamic load coming from train, it has great influence in absorbing the coming static load from train too. Deformed shape, Stress, and displacement due to the static load is presented, the comparison is made due to variation of rail pad type (soft, Hard, Normal, EVA) and K&C value, at the edge and centre point of loading. The Stress, Vertical acceleration and displacement are analysed for a range of K&C value, speed for the dynamic analysis.
For the static load analysed, for the two different point loading, the y (vertical) displacement /deformation/ decreased as both stiffness and damping increased and remain constant when the stiffness increase and damping value remain constant. The value of stress increased when we change the pad from soft to normal, gets reduced for the other twocases i.e. From Normal to hard, and hard to EVA. For the dynamic case the value of Vertical acceleration or vibration increase as both stiffness and damping increased, and also when the speed is increased from 22.22m/s -33.33m/s the acceleration behaves the same. The vertical displacement remains the same for K &C change with in interval of increase provided for both, while it gets reduced for the increase in the speed. The value of stress decreases as the K & C increase and increase while the speed increase.
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Keywords
Resilient, Vibration, Filter, Dynamic load, Rail pad,, ABAQUS, ANSYS, Static load, Spring and Dashpot, Speed, Displacement, Acceleration, K&C