A MULTIDISCIPLINARY PLATFORM FOR FUTURE TRIBOLOGICAL MODELLING

Lead Research Organisation: Imperial College London
Department Name: Dept of Mechanical Engineering

Abstract

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.

Planned Impact

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.

Publications


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Forte A (2016) A composite hydrogel for brain tissue phantoms in Materials & Design
Forte AE (2016) On the characterization of the heterogeneous mechanical response of human brain tissue. in Biomechanics and modeling in mechanobiology
 
Description We have developed new methodologies to model interactions between surfaces at different scales.
Exploitation Route Can be exploited to design better systems and components in different industrial sectors
Sectors Aerospace, Defence and Marine,Chemicals,Digital/Communication/Information Technologies (including Software),Energy,Healthcare,Manufacturing, including Industrial Biotechology,Transport
 
Description Methodologies developed now adopted by some of the indusrial project partners (Bosch, BP, Shell...)
First Year Of Impact 2016
Sector Aerospace, Defence and Marine,Chemicals,Energy,Healthcare,Manufacturing, including Industrial Biotechology,Transport
Impact Types Societal,Economic
 
Description Collaboration with BP to work on multiscale modelling of fluid lubrication 
Organisation BP (British Petroleum)
Country United Kingdom of Great Britain & Northern Ireland (UK) 
Sector Private 
PI Contribution Professor Dini's resaerch team involved in developing methodologies to develop MD-continuum coupling across the scales; one PDRA and one PhD student funded so far through the BP-ICAM programme.
Collaborator Contribution Funded a programme of research feeding directly into the fellowship - BP-ICAM 23 (1 year PDRA and PhD studentship via the EPSRC Theory and Simulation of Materials CDT).
Impact Softaware developed for coupling; implementation on BP cluster and training of potential users.
Start Year 2014
 
Description Collaboration with Bosch to improve design and performance of windscreen wipers 
Organisation Bosch Group
Department Robert Bosch Produktie N.V.
Country Belgium, Kingdom of 
Sector Private 
PI Contribution We have developed both experimental and modelling techniques to study sealing and wiping properties or rubber components. A PhD student, Alexis Wang, has been working specifically on thsi project with Professor Dini's research team.
Collaborator Contribution Sponsored a PhD studentship - development of modelling tools followed experimental studies carried out in a previous programme (2011-2015). Th eproject partner also provided experimental data, materials, finite element models and monthly meeting with their research teams in Belgium and Romania.
Impact Developed a methodology to predict friction and film thickness in wiper blades.
Start Year 2015
 
Description Collaboration with Dr Benat Gurutxaga-Lerma - Junior Research Fellow at Trinity College Cambridge 
Organisation University of Cambridge
Department Cambridge Stem Cell Institute
Country United Kingdom of Great Britain & Northern Ireland (UK) 
Sector Multiple 
PI Contribution I have established a long-term collaboration with Dr Gurrutxaga-Lerma on the study of dislocation and plasticity in solids. Our team contributes in the development of links between dislocaton motion and damage and Dr Daniel Balint and Professor Adrian Sutton at Imperial are also actively involved in this collaboration.
Collaborator Contribution Development of modelling tools to study dislocations and plasticity.
Impact A number of papers in preparation and published. Multidisciplinary collaboration: material science, physics and tribology/engineering
Start Year 2016
 
Description Collaboration with Element Six to study polycrystalline diamond sintering and cutting performances 
Organisation De Beers Group
Department Element Six
Country Luxembourg, Grand Duchy of 
Sector Private 
PI Contribution Expertise in development of multi-scale models to study sintering and fracture of polycrystalline diamonds.
Collaborator Contribution Funding of a studentship through the EPSRC DST CDT (and also the end of a EPSRC TSM CDT studentship), and significant materials, equipment and staff time.
Impact Predictive tools being developed to improve cutting tols for Oil and Gas
Start Year 2015
 
Description Collaboration with Ford to improve design of engine components via texturing 
Organisation Ford Motor Company
Country United States of America 
Sector Private 
PI Contribution Expertise in developing modelling tools to improve performance of textured surfaces and performing experimental measurements - collaboration with Dr Tom Reddyhoff in Professor Dini's group.
Collaborator Contribution One year Post-doctoral researcher funded to conduct experimental tests to be used to validate the models. Also contributed in staff time and materials.
Impact New design tools to predict effect of cavitation on performance of lubricated textured surfaces and comparisons with experiments - ongoing research.
Start Year 2016
 
Description Collaboration with LANZHOU INSTITUTE OF CHEMICAL PHYSICS to study frictional behaviour and hydrogel and new synthetic constructs for superlubrication 
Organisation Chinese Academy of Sciences
Department Lanzhou Institute of Chemical Physics
Country China, People's Republic of 
Sector Academic/University 
PI Contribution Multi-sacle modelling expertise for soft solids and hydrogels
Collaborator Contribution Development of new synthetic bio-inspired constructs to reduce friction and superlubrication
Impact Two papers currently submitted and under review
Start Year 2016
 
Description Collaboration with Shell to study liquid foams and additive properties 
Organisation Shell Global Solutions UK
Country Netherlands, Kingdom of the 
Sector Private 
PI Contribution Expertise in the development of models and experiments to study foaming in lubricants and complex fluids - collaboration between tribology and thermofluids via the Shell University Technology Centre. Also, extensive study of effect of organic friction modifiers on boundary friction reduction in metal contacts.
Collaborator Contribution A full PhD studentship via teh Shell UTC and a EPSRC Case conversion directly linked to the fellowship. UTC manager time for co-supervision and materials/equipment.
Impact Publications: see articles by Ewen, Dini and co-authors Award won for video: http://gfm.aps.org/meetings/dfd-2016/57d9c980b8ac3117910009a0 Multi-disciplinary: fluid mechanics, physical chemistry and tribology
Start Year 2014
 
Description Collaboration with the University of Swinburne to study theories for lubricants slip and multi-scale modelling 
Organisation Swinburne University of Technology
Department Department of Mathematics
Country Australia, Commonwealth of 
Sector Academic/University 
PI Contribution Started a collaboration with Professor Billy Todd's group (Head of Department) to work on the origins of friction and wall slip in lubricated system. The aim is to improve our understanding and develop new modelling techniques for complex fluids in tribological problems. Our team provides the expertise for modelling lubricated systems and comtinuum and molecular level.
Collaborator Contribution Fundamental expertise in developing mathematical tools and formulations to study fluids in confinement using non-equilibrium molecular dynamics
Impact Application to the Australian Research Council (ARC) for collaborative funding has been made in February 2017.
Start Year 2016
 
Title Coupling library for MPI codes based on domain decomposition. 
Description CPL_library currently facilitates a domain-decomposition style of coupling. A typical supported example scenario would be: a CFD program solves the continuum equations in the upper region of a domain and an MD simulation solves discrete-particle equations of motion in the lower region. The two programs exchange data (using CPL_library) to ensure selected field variables are consistent where the MD and CFD domains overlap. The library provides a clear and minimal interface for communicate data within the this overlap region using MPI communications. Mapping of the geometry to processor the topology is automatically handled internally. The library provides interface for Fortran, C/C++ and Python, therefore codes written in different programming languages can be coupled. 
Type Of Technology Software 
Year Produced 2016 
Open Source License? Yes  
Impact By making this code opensource, our intention is to ease the step of research community into multi-scale simulations using domain decomposition techniques. 
URL http://www.cpl-library.org
 
Description BP ICAM Conference (Manchester 2016) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other audiences
Results and Impact A presentation was given to an audience of about 50 people in the yearly conference BP-ICAM (International Centre for Advanced Materials) organises. This is an event where researchers working in collaboration with BP from Manchester, Imperial College, Cambridge and Illinois universities attend to share about their respective projects. This was a good opportunity to share knowledge and get feedback about how to make our research have an impact in solving real-life industry problems related to lubrication.
Year(s) Of Engagement Activity 2016
 
Description Multi-scale Materials Modelling conference (Dijon 2016) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other audiences
Results and Impact A presentation of 20 minutes was given to an audience of about 70 researchers in the field of lubrication and wear modelling at the MMM2016 conference. The aim was to show how to employ a multi-scale approach (coupling Molecular Dynamics with CFD by using domain decomposition) to model lubricant films. The presentation was followed by a round of comments and questions where some researchers expressed their interest in the work we have been carrying out.
Year(s) Of Engagement Activity 2016
 
Description TYC (Thomas Young Centre) conference (London 2016) 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Postgraduate students
Results and Impact A poster was made for the postgraduate day of TYC centre held at Imperial College London. Postgraduate students and academics from Imperial College and other London universities gather for a day to showcase their respective research projects. We participated in the poster session where people approached us to know more about the MD-CFD method we are using to model lubricant layers.
Year(s) Of Engagement Activity 2016