Analysis of Fatigue Failure on Motor Powered Train Axle of AALRT

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Date

2017-06

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Publisher

Addis Ababa University

Abstract

Fatigue is one kind of phenomena that results breakdown of such material that are under a cyclic load or repeated stress. Fatigue is a main process resulting in a structural degradation and failure during axles’ service life. Railway axles are commonly operated over a service life of 30 years or more which refers to a very high number of loading cycles in the order of 10 iii 9. This project is all about AALRT train axle failures due to fatigue and discus about how to analyze the fatigue and stress. The reason why the project idea directed to around this area is that nowadays AALRT is operating beyond its design limit. The train designed to load 8 persons in one meter square space in the condition of overload. But practically the train is operating by loading more than 8 passengers in one meter square space. When the train load and operates beyond its design load limit many parts of the train life span will be shorten. One of the sensitive parts of the train that could easily damage and may cause derailment accident is axle. Because the whole train load directs toward to the axle. So the train axle will subject to fatigue and finally failure. The objective of this project is analyzing the axle of AALRT to clearly specify its fatigue life and stress concentration and distribution. This is done by collecting the data from ERC and Internet and analyzing the data that collected using formulas and software. The result will be discussed by comparing the axle fatigue life with the standard axle fatigue life.. And it tried to show that stress analysis by using software like Abacus. According to the data collected and by using approaches and software At Leghar station which is on the worst loading condition the result of the Maximum Principal Stress and the von misses stress are N/m 2 2017 and N/m 2 respectively. The result of the pressure is N/m 2 . The reaction force is N. The fatigue life is calculated as cycles. . When comparing with the standard axle life it’s found that the life of the AALRT axle life has less fatigue life. According to the standard axle life the cycle of the fatigue life reaches more than Giga cycles. The result validates and it is proven. Therefore AALRT should load passengers according to its design load limit and adding additional trailer will make less and disperse the concentrated axle load. Another solution is that using better fatigue resistant material for the axle would make longer the life of the axle.

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Keywords

Motor Powered Train, Axle, AALRT, Fatigue Failure

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