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Title: A galling failure model : development of predictive framework for iron based hardfacings based on crystal plasticity finite element
Author: Barzdajn, Bartosz
ISNI:       0000 0004 7963 7345
Awarding Body: Imperial College London
Current Institution: Imperial College London
Date of Award: 2019
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An investigation of rough metal to metal contacting surfaces under normal load and undergoing sliding has been carried out with explicit representation of measured surface profiles within a crystal plasticity finite element formulation in which grain size, texture and slip properties are incorporated. A new metric called plastic reach has been introduced for contacting surfaces which reflects both the magnitude of the local surface asperity plasticity and its spatial reach. This quantity has been shown to obey a power law relationship with the applied normal load for sliding contact which in turn has been related to a hazard function. In this way, a new methodology to predict the galling frequency that follows a Weibull distribution has been established. Additionally, a quantitative definition of galling for the class of metal on metal contacting surfaces is considered. The predicted galling frequency distribution for a 316 stainless steel has been compared with independently experimentally measured galling frequencies showing good agreement. An assessment of confidence limits has also been provided for the modelling methodology, followed by sensitivity studies. The latter resulted in first recommendations for our industrial partner, on how to improve galling resistance of hardfacing alloys.
Supervisor: Dunne, Fionn Sponsor: Rolls-Royce plc ; Imperial College London
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral