Development of an integrated numerical method for the fatigue analysis of railway bogies

Nickerson, Brendon Mark (2017-03)

Thesis (MEng)--Stellenbosch University, 2017.

Thesis

ENGLISH ABSTRACT: This study focuses on the creation of a numerical simulation process that can be used to determine the fatigue life of railway bogies, using the Commonwealth railway bogie of the class 5M train in South Africa as example. The numerical simulation is intended for use in future research on railway bogies. The research is supported and funded by the Passenger Rail Agency of South Africa (PRASA) Engineering Research Group at Stellenbosch University. A finite element (FE) model of the bogie has been created using an accurate three dimensional computer aided drawing (CAD) model, supplied by the PRASA Engineering Research Group. The FE model has been used to determine stress distributions due to unit loads applied at the primary and secondary suspension attachment points. Dynamic load cases have been determined through simulation of spring-mass-damper models representing the train and track systems. The load cases have been applied to the FE model stress distributions and superimposed to obtain stress histories. A script has been coded in Python to determine fatigue life from the stress histories. The process has been designed in such a way that each component can be altered and refined, allowing future research opportunities and refinements such as expanding the process to be applied to other bogies or allowing actual measured track data to be used as input for determining dynamic loads. Further research is required to validate and improve the numerical process.

AFRIKAANSE OPSOMMING: Hierdie navorsing fokus op die daarstelling van ’n numeriese proses wat gebruik kan word om die vermoeidheidslewe van spoorlyn draaistelle te voorspel. Die "Commonwealth" spoorlyn draaistel van ’n Suid Afrikaans 5M trein word as voorbeeld gebruik. Die navorsing word ondersteun en befonds deur die "Passenger Rail Agency of South Africa (PRASA) Engineering Research Group" by Stellenbosch Universiteit. ’n Eindige element (EE) model van die draaistel was geskep deur die gebruik van ’n akkurate drie dimensionele rekenaargesteunde tekenprogram model, wat deur die PRASA Engineering Research Group verskaf is. Die EE model is gebruik om die verspreiding van die spanning in die draaistel te bereken as gevolg van eenheidslaste op die primêre en sekondêr veringstelsel punte. Dinamiese lasgevalle is deur die gebruik van ’n veer-massademper model van die trein en spoor sisteme bepaal. Die lasgevalle is op die EE model se spanningsvelde toegepas en gekombineer om die spanninggeskiedenis te bepaal. Die kode wat hierdie geskiedenis gebruik om die vermoeidheidslewe te voorspel, is in Python geskryf. Die hele proses is ontwerp so dat elke komponent op sy eie verfyn kan word. Dit skep verdere navorsingsgeleenthede soos studies op ander draaistelle of die gebruik van gemete spoor data as inset vir die dinamiese model. Verdere norvorsing is nodig om die proses te verbeter en geldig te maak.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/101072
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