Thesis (MEng)--Stellenbosch University, 2017.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
