A MULTIDISCIPLINARY PLATFORM FOR FUTURE TRIBOLOGICAL MODELLING

Almost all engineering systems and many biological ones contain components that are loaded and rub against one another, such as gears and bearings in machines and hip and knee joints in humans. This rubbing results both in friction, that wastes energy, and in wear and other forms of surface damage that lead to machine (and human) downtime, and the need for expensive repair and replacement. This whole field of research is called Tribology and is pivotal both in the quest for sustainability, including reducing CO2 emissions, and in improving the quality of our lives.

In Tribology the effects of rubbing, such as frictional dissipation and wear, are perceived as macroscale phenomena and are traditionally studied by macroscale experiments and analysis. However they actually originate at the atomic and molecular scale, where the severe local stresses produced by rubbing cause restructuring of surface layers, while the molecules of lubricant in rubbing contacts interact with and protect surfaces. Thus to understand and so improve tribological systems we need an approach that spans the molecular, meso- and macro-scales. This will yield both information as to the origins of friction and surface damage - and unwanted phenomena are best tackled at their roots - as well as the ability to design macro-scale components such as lubricants, bearings, gears, engines and replacement joints that operate reliably and efficiently for as long as required.

To meet this need, the proposed research will develop and apply advanced techniques to model rubbing contacts at all the necessary scales - atomic/molecular simulations of surfaces and lubricants, meso-scale modelling looking at structural evolution of surfaces due to rubbing, and macro-scale simulations of actual rubbing components such as bearings and engines. These simulations will be validated by experiments that also span the same range of scales, including direct observation of molecules in rubbing contacts. The most critical and innovative stage of this project, however, will be to link all these models together in to a single computer-based package. The result will be a set of modelling programs that can be used in many different ways; for example to explore the origins of tribological phenomena; to optimise lubricant surface and materials design; to predict performance of machines based on a combination of design and underlying atomic/molecular processes.

Such an approach will give us tools both to understand in full tribological phenomena such as friction and wear and to enable effective "virtual testing", where new and novel designs, lubricants and surfaces can be combined and their effectiveness tested prior to recourse to time-consuming and expensive experimental development.

Improved tribology capabilities are central to maximising energy efficiency, raising the quality of engineering materials and assuring the safety of engineering systems. Advanced research in tribology is therefore a vital ingredient for the sustainable future of UK industry. This Fellowship aims at transforming modelling strategies in this area. This requires underpinning primary knowledge and integration of techniques across different disciplines, the latter of which is at present woefully lacking. My pioneering academic work will be managed through to application in order to maximise its impact on society and the economy.

The immediate beneficiaries of this Fellowship will be my industrial partners (and later also other companies) that need to reduce friction in order to achieve energy savings, especially in additive manufacturing, oil & gas, automotive and aerospace. The new modelling techniques and the integration of modelling tools across the scales proposed by the applicant will enable (i) the development of new solutions in terms of lubricant and additives (Afton, BP, Shell); (ii) the optimisation of surfaces to reduce friction in many engineering components (Caterpillar, Ford, Rolls-Royce); the design of new materials that accounts for chemo-mechanical interactions and the interplay between fluids and solids (Bosch).

Research on predicting damage initiation and evolution of contacting surfaces will also directly impact industries whose interest is to improve reliability, reduce life cycle cost and resolve high-profile issues related to tribology. This will include developing strategies to (i) predict premature wind turbine (WT) bearing failures, whose root causes are not yet fully understood, and thus sustain wind energy generation (SKF); (ii) prevent catastrophic failure due to contact fatigue, which can place people's lives at risk, and pave the way to the development of transmission systems for the next generation of gas turbines and IC engines (Rolls-Royce, Caterpillar); (iii) reduce shutdown time for oil & gas extraction by improving the understanding of the drilling process and optimising cutting tools for operations in harsh environments (Element Six).

The Fellowship will have direct effect on environment and healthcare; for example, the development of new bearings for the nuclear industry will reduce radioactive waste/contamination (Rolls-Royce Nuclear), improved machine efficiency will reduce in CO2 emissions and joint replacements based on tribologically-sound design will improve quality of life. Finally, the proposal is linked to essential discoveries for the development of biomaterials and new nanotechnologies.

In order to ensure that the research undertaken in this Fellowship fits industrial needs, I have approached nine companies (Afton, Bosch, BP, Caterpillar, Element Six, Ford, Rolls-Royce, Shell, SKF), with whom I have already collaborated, to identify important applications. These companies have all agreed to directly fund and support 12 studentships and research linked to one or more specific WPs. The strong commitment and investment of these partners is accompanied by a clear strategy to facilitate knowledge transfer. Each company has identified areas in which their staff members will be directly involved in the research and trained on the use of the software via masterclasses on the use of the newly developed integrated software TriboSIM and linked packages on HPC facilities. Free access to the software for research purposes will be provided to all project partners and bi-annual meetings will review the progress in terms of implementation, scalability and user interfaces generated by the Fellow's team. The industrial partners will also host PhDs and PDRAs to optimise knowledge exchange and to test the findings of the project using their research facilities.