Effects of Radius of Curved Rail on Rail Wear

Abdulhakim, Seid (2015) Effects of Radius of Curved Rail on Rail Wear. Masters thesis, Addis Ababa University.

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Abstract

One of the most sensible issues in the railway industry is the impact on infrastructure of train operations and the damage on vehicles provoked by the track conditions. These issues have a significant impact on the life cycle costs of the railway networks. The study of vehicle-track interaction is important in reducing the operation and maintenance costs, by increasing the life cycle of both vehicles and tracks, and increasing the speed, safety and comfort indexes of the railway systems. This thesis focused on the analysis of effects of radius of curved rail on rail wear. Multi-Body simulation software SIMPACK is employed to create a one car railway vehicle model with two bogies with an axle load of 10 ton. The rail material which is applied on the study is UIC 60 standard carbon steel. To verify the simulation results, the SIMPACK model is run on varies track radius (sharp curves) range from 100 m to 800 m under dry condition. Parameters like track radius, wheel rail contact patch area, contact pressure, vehicle speed, wheelset yaw angle are investigated to analyse there effects on rail wear. The dynamics in the vehicle to the rail on canted curve was analyzed using a quasi-static approach which at instant time the vehicle is loaded vertically by its weight and laterally by centrifugal force. This lateral force is balanced by using centripetal force and its direction may be inwards and outwards depending on velocity and weight of the vehicle. It is applied on outer rails while the vehicle is moving above equilibrium speed and it is applied at the inner rail while the vehicle is moving below equilibrium speed. The increase in radius of the rail has exponentially decrease the wear conditions at constant velocity on curved track at both rail head. The outer rail side is damaged severely when the vehicle is moving above equilibrium speed and the inner rail side is damaged severely when the vehicle is running below equilibrium speed. Wheel rail contact patch area increases with decreasing of radius of rail at the same time the wear volume also increases. Contact patch area and wear rate have direct relationship. Contact pressure and track radius have direct relation. As track radius increases contact pressure decreases due to decrease of contact patch area. Wheelset yaw angle has inverse relation with radius and direct relation with that of contact patch area and wear of rail. All above parameters affecting wear property of rail should have to be controlled to minimize damages on rolling stock and rail. Curved railway tracks requires more attention than that of straight track due to the introduction of centrifugal force which makes the vehicle tends to move laterally during curving motion. Severity of wear can be reduced using equilibrium speed of the vehicle and following vehicle speed restriction on curves is important otherwise leads to excessive wear on the contacting surfaces. Interchanging of inner rail and outer rail can be considered as a means to lengthen the service life of the rail. Generally knowing the effects of these parameters on overall system helps for understanding the mechanism, minimize damages on rail and can be added for practical rail way curved track design and speed restriction on curves.

Item Type:	Thesis (Masters)
Uncontrolled Keywords:	Mechanical Engineering
Subjects:	H Social Sciences > HE Transportation and Communications T Technology > T Technology (General) T Technology > TF Railroad engineering and operation T Technology > TJ Mechanical engineering and machinery T Technology > TL Motor vehicles. Aeronautics. Astronautics
Divisions:	Africana
Depositing User:	Andriamparany Edilbert RANOARIVONY
Date Deposited:	27 Nov 2018 09:09
Last Modified:	27 Nov 2018 09:09
URI:	http://thesisbank.jhia.ac.ke/id/eprint/7637

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