Railway Engineering

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Browsing Railway Engineering by Subject "ABAQUS"

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    Analysis on the Influence of Rail Pad on Ballasted Railway Track
    (Addis Ababa University, 2018-07-09) Belete, Lemma; Mathias, Kabtamu (Mr.)
    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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    Experimental Investigation and Production of Track Resilient Pads From End-of-life Tyres and its Application
    (Addis Ababa University, 2016-07) Zewdie, Moges; Asnake, Adamu (PhD)
    In rail way industry, vibration and structure- born- noise emission due to wheel-rail interaction disturbs the surrounding environment and the rail track structures. One of the solution for these specific problems is using more resilient materials in track structures like rail pads, sleeper pads, sleeper boots or ballast mats, which can be produced using natural rubber and recycled end-of-life tyres. The core attention of this thesis is composing and producing railway track resilient materials from natural and recycled rubber. Track resilience pads are one of track structural components which isolate the steel rail from the concrete sleeper to protect the sleeper from damage. It has also vibration and load distribution effect due to its elasticity. The new composite material contains elastomers, fillers activators, accelerators, plasticizers, anti-oxidants and volcanizing agent. In order to achieve the standard quality of the resilient pads, more than 12 composites are prepared and basic rubber quality tests are carried out. The resilient material qualities are checked based on Australian, Chinese and Indian standards. Standard quality tests such as Shore A hardness, tensile strength, elongation, aging, wear resistance, stiffness and constant compression set tests are conducted. In addition, rhioline and viscosity tests are conducted to control the curing environment and the process ability of the resilient pad compound respectively. Once the required compound quality has achieved, by preparing steel rubber pad mold the final shape of a rail pad is produced using product curing machine. Finally, railway Slab Track Bridge is modeled and analyzed with and without sleeper pad using finite element package ABQUS to illustrate the application of sleeper resilient pads in reduction of the dynamic loading effect. The result shows application of resilient rail pads and sleeper pads together reduce the vibration and stress of the slab track.