EngD in Extending rail life through metallurgical understanding of modern rail steels

This project is based at the Department of Mechanical Engineering at the University of Sheffield, and is sponsored by Network Rail Infrastructure Limited. We are seeking a candidate with a 2.1 or 1^st class degree in a STEM discipline.

Rail is a crucial component of the UK’s future low carbon sustainable transport system both for freight and passenger use. The rails themselves are central to safe operation and maintenance costs of the system, controlled by the interaction of their metallurgy and the external loads imposed on them. This project approaches this problem across a range of sizes (nano-, micro- and meso-scale) to explore how modern rail steels can better meet the physical demands placed on them. This will be achieved through a combination of modelling and experimental investigation, combined with data and expertise on application of the materials from Network Rail. Techniques required and the balance of experimental vs modelling research can be adjusted to meet the skills and interests of the student.

Network Rail and the wider rail industry has developed the ‘T-Gamma’ based Whole Life Rail Model to better understand rail rolling contact fatigue crack initiation and its interaction with rail wear. This has been developed semi-empirically and only validated for historical performance of older ‘normal grade’ rail materials, not for any of the current premium rail materials. For application to modern rail steels and emerging rail coating technologies there is a need to understand how these materials respond to wheel/rail forces to determine where on the network they can be more resistant to damage development and give longer life. Currently this is only possible through time consuming 'trial and error', missing the contribution possible through metallurgical understanding. Improved understanding will bring:

• Location specific targeting of rail materials to traffic demands.
• Reduced rail grinding maintenance as rail damage is reduced.
• Materials selection based on metallurgical behaviour in service conditions rather than using unrepresentative tensile tests.

Recently completed Network Rail research at University of Sheffield has identified a new method to extract rail steel metallurgical properties from rails removed from service. Our UKRRIN (UK Rail Research Innovation Network) suite of equipment in Sheffield includes state-of-the-art nano-indentation, micro-hardness and microscopy facilities for exploring metallurgical properties, plus closely controlled full and small-scale rail-wheel contact simulation in the laboratory. The UKRRIN investment has provided a unique concentration of equipment to drive this investigation across the length scales from roughness to macro contact behaviour. In combination Sheffield’s facilities and modelling expertise can dramatically add value to existing trial rail installations through deriving the properties needed for predictive modelling under a range of traffic conditions. Research areas addressed will include:

• Determining the material parameters for input to models of rail steel performance
• Opportunity to work with novel materials already in trial sites on the network (this dramatically accelerates output relative to starting new trials)
• Use outputs from vehicle dynamics simulations at Network Rail to specify a range of traffic loads.
• •Augment data from track tested rail with samples tested in Sheffield’s lab facilities.
• Conduct modelling of rail degradation based on plastic damage accumulation and derive links to the ‘damage functions’ used in network wide modelling
• Set the future agenda for rail steel development by determining characteristics required of a rolling contact fatigue resistant material
• Provide tools for evaluation of rail materials under combined traction and steering forces plus environmental influences (lubrication, water, varying adhesion levels).

This project is an excellent opportunity to explore the role of materials and metallurgy in a highly visible public service context, and to gain industrial experience alongside your research.

The Centre for Doctoral Training in Advanced Metallic Systems is a partnership between industry and the Universities of Sheffield, Manchester and I-Form Advanced Manufacturing Centre, Dublin. CDT students undertake a 4-year doctorate with an in-depth compulsory technical and professional skills training programme. Please review our training programme, application process and full entry requirements at www.metallicscdt.co.uk.

For more information on the research scope of the project please contact David Fletcher at [Email Address Removed]. Informal enquiries about the CDT training programme should be sent to [Email Address Removed].

Please note that this project will close before the advertised end date if a suitable applicant is secured. We suggest that you do not delay submitting your application.