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Wear fatigue in nickel superalloys. / Shaun Gareth Watkins

Swansea University Author: Shaun Gareth Watkins

Abstract

To date, work to assess the progression of wear and the effects of wear damage on low cycle fatigue has tended to be focused on specific components and their operating conditions. Although effective in the short term to solve today’s problems, these efforts often deliver insufficient understanding o...

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Published: 2015
Institution: Swansea University
Degree level: Doctoral
Degree name: EngD
URI: https://cronfa.swan.ac.uk/Record/cronfa43108
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Abstract: To date, work to assess the progression of wear and the effects of wear damage on low cycle fatigue has tended to be focused on specific components and their operating conditions. Although effective in the short term to solve today’s problems, these efforts often deliver insufficient understanding of the overall design space limits to have much influence of future component design.Therefore, the following research attempts to understand how wear damage progresses and how it impacts on fatigue performance in order to develop more accurate lifing models to predict the behaviour and life of real engine components.In order to do this, a survey of the internal Rolls-Royce database and public literature on wear damage on components from ex-service and current service engines was performed. Information relating to the wear scar morphologies in the reports was extracted as well as physically measuring and analysing wear damage on worn components within the Rolls- Royce failure investigation department. The wear damage was then replicated onto Udimet720Li laboratory fatigue specimens by a means of altering the pad pressure and pad sliding distance to produce a range of wear damage in order to carry out fatigue testing. Fatigue testing of the damaged specimens allowed fatigue knockdown factors to be calculated to determine the impact of wear on the fatigue life.A fretting fatigue rig was also designed and built for this research to focus on in-situ fretting fatigue at high temperatures of 600°C.
Keywords: Metallurgy
College: College of Engineering