EventsProf. Daniele Dini

A Multidisciplinary Approach to Modelling in Tribology: from Atoms and Molecules to Engineering Applications

Tribological phenomena are governed by events and mechanisms which find their roots at the small scales, even more so in environments where mechanical and chemical effects are intimately coupled.  For example, nano-scale thermal and particle emission events control the formation of antiwear additive films and oxidation; surface damage, such as crack initiation and wear, results from the accumulation of strain at dislocations level; corrosion events are triggered and controlled by molecular interactions. The key challenge addressed in this talk is the need for the development of robust methodologies for the integration of the skills and techniques recently developed by our modelling team at different scales (see e.g. [1-13]) to capture physical, chemical and mechanical processes and interactions across the scales via multi-physics modelling strategies – this is schematically depicted in the attached figure. Example of modelling methodologies developed and employed to solve problems at specific length- and time-scales will be presented with particular emphasis given to nano-scale models and processes, before concentrating on coupling strategies to be adopted to shed light on macro-scale tribological events while zooming-in to understand their governing mechanisms.  Various applications will be discussed ranging from automotive and aerospace to biomedical engineering.

Keywords: tribology, contact mechanics, lubrication, multi-physics, molecular dynamics, multi-scale modelling, computational methods

Figure 1. Schematic representation of the intrinsic complexity and multi-scale nature of tribological problems and tools required to understand the mechanisms that govern frictional response in real applications.

[1] Verschueren, J., Gurrutxaga-Lerma, B., Balint, D.S., Dini, D., Sutton, A.P., “The injection of a screw dislocation into a crystal: Atomistics vs. continuum elastodynamics”, Journal of the Mechanics and Physics of Solids (2017) 98, 366-389.

[2] Profito, F.J., Vlădescu, S.C., Reddyhoff, T., Dini, D., “Transient Experimental and Modelling Studies of Laser-Textured Micro-Grooved Surfaces with a Focus on Piston-Ring Cylinder Liner Contacts”, Tribology International (2017), in press.

[3] Ewen, J.P., Gattinoni, C., Morgan, N., Spikes, H.A., Dini, D., “Nonequilibrium Molecular Dynamics Simulations of Organic Friction Modifiers Adsorbed on Iron Oxide Surfaces”, Langmuir (2016) 32, 4450-4463.

[4] Bodnarchuk, M.S., Heyes, D.M., Breakspear, A., Chahine, S., Edwards, S., Dini, D., “Response of Calcium Carbonate Nanoparticles in Hydrophobic Solvent to Pressure, Temperature and Water”, J. Phys. Chem. C (2015), 119(29), pp. 16879–16888.

[5] Putignano, C., Carbone, G., Dini, D., “Mechanics of Rough Contacts in Elastic and Viscoelastic Thin Layers”, Int. J. Solids Struct. (2015), doi:10.1016/j.ijsolstr.2015.04.034.

[6] Gurrutxaga-Lerma, B., Balint, D.S., Dini, D., Eakins, D.E., Sutton, A.P., “Attenuation of the Dynamic Yield Point of Shocked Aluminum Using Elastodynamic Simulations of Dislocation Dynamics”, Phys. Rev. Letters (2015), 114, 174301.

[7] Smith, E.R., Heyes, D.M., Dini, D., Zaki, T.A., “A localized momentum constraint for non-equilibrium molecular dynamics simulations”, J. Chem. Phys. (2015), 142 (7), 074110.

[8] Medina, S., ,Dini, D., “A numerical model for the deterministic analysis of adhesive rough contacts down to the nano-scale”, Int. J. Solids Struct. (2014), 51(14), pp. 2620–2632.

[9] Gattinoni, C., Maćkowiak, S., Heyes, D.M., Brańka, A.C., Dini, D., “Boundary-controlled barostats for slab geometries in molecular dynamics simulations”, Phys. Rev. E (2014), 90 (4), 043302

[10] Gattinoni, C., Heyes, D.M., Lorenz, C., Dini, D., “Traction and non-equilibrium phase behaviour of confined sheared liquids at high pressure”, Phys. Rev. E, 88, (2013), 052406.

[11] Bertocchi, L., Dini, D., Giacopini, M., Fowell, M.T., Baldini, A., “Fluid film lubrication in the presence of cavitation: a mass-conserving two-dimensional formulation for compressible, piezoviscous and non-newtonian fluids”, Tribol. Int., 67, (2013), pp. 61–71.

[12] Heyes, D.M., Smith, E.R., Dini, D., Spikes, H.A., Zaki, T.A., “Pressure dependence of confined liquid behavior subjected to boundary-driven shear”, J. Chem. Phys. (2012), 136 (13), 134705.

[13] Smith, E.R., Heyes, D.M., Dini, D., Zaki, T.A., “Control-volume representation of molecular dynamics”, Phys. Rev. E (2012), 85(5), 056705.

About The Speaker

Daniele Dini is a Professor and Head of the Tribology Group at Imperial College London.  His main research interests are in the application of advanced modelling and experimental strategies to tribology (friction, lubrication, wear, surfaces and interfaces) and structural integrity with a focus on (i) research on fundamental and theoretical aspects of molecular dynamics, soft matter physics, lubricant and additives, fluid/solid interactions, surface damage, wear, and biomechanics, (ii) development of experimental techniques, numerical tools and software for the solution of advanced soft matter, physical chemistry, tribological, biomechanical and structural problems, and (iii) development of multi-physics solvers and multi-scale coupling strategies.  He has a strong track record of research in a number of research areas, including nanotechnology, tribology, fatigue and fracture, biomechanics, super-hard polycrystalline materials, and industrial collaborations with many companies (Afton Chemical, Bosch, BP, Caterpillar, Element Six, Ford, Rolls-Royce, Shell, SKF, Toyota). He has established research activities with academic collaborators across the UK but also in China, USA, Brazil and Europe, and has attracted a large number research grants from industrial sponsors and national and international funding bodies. He has recently been awarded a prestigious EPSRC Established Career Fellowship to build a multi-disciplinary platform for modelling in tribology.  He sits on a number of national and international advisory and editorial boards. He has published over 150 papers in international journals and presented a number of invited talks and contributions at conferences in the areas of tribology, chemical physics, soft matter physics, fatigue, fracture and biomechanics. He is the recipient of four best paper awards and many other personal awards.