Dynamics Research Group
We are internationally recognised as a leading group in the fundamentals of multi-body dynamics and its applications to all forms of machines and mechanisms.
We are also widely recognised for leading edge research contributions to the area of tribo-dynamics, from nano-scale interactions to micro-scale tribology and further to the integration of the same in multi-body analysis.
The Dynamics Research Group (DRG) undertakes research across a broad scale of physics of motion from fundamentals to the many application areas, with emphasis in the automotive, engines, powertrains, bearings, mechanical seals and pharmaceutical areas. Two main themes underlie the research effort;
- energy efficiency and conservation, and
- noise, vibration and harshness (NVH) refinement.
The group has a long standing track record of research funding from national funding bodies; Engineering and Physical Sciences Research Council (EPSRC) and DTI (Department of Trade and Industry)/TSB (Techbnology Strategy Board). Furthermore, DRG has had a very long established record of successful collaboration with industry in the UK as well as world-wide. DRG has received research grants and contracts in excess of £7 M in the past decade or so.
Broadly, the areas of research fall into the following categories:
Fundamentals of kinetic interactions at fractal-level wet rough surface topography, including adhesion, elastio-plastic deformation, solvation, van der Waals attraction – electrostatic repulsion, molecular adsorption and formation of low shear strength ultra-thin fluidic films.
Multi-physics approach to micro-scale tribology, including boundary/mixed micro-thermo-elastohydrodynamics and/or multi-phase flow CFD with discrete phase Langrangian dynamics with a broad range of applications to bearings, seals, all IC engine conjunctions (www.encyclopaedic.org) , transmission systems and vehicular differential units.
Mitigation of friction through advanced surface coating technologies, surface texturing, including laser processing, indentation techniques and texture optimisation through numerical analysis (www.encyclopaedic.org)
Impact dynamics in lubricated contacts or stick-slip friction, pressure perturbation, structure-borne wave propagation and acoustic emission with application to a host of major NVH problems such as piston slap, transmission rattle (www.transmission-rattle.com), axle whine and driveline elasto-acoustic coupling (clonk) (www.transmission-rattle.com) in automotive applications and actuation squeak in dry powder pressure metered dose inhalers (pMDI).
Analysis of underlying mechanisms of cavitation in tribological contacts using thermal multi-phase flow computational fluid dynamics with bubble dynamics as dispersed Lagrangian phase with bubble stability through Rayleigh-Taylor criterion (www.cavitation-institute.org)
Vehicle dynamics with multi-body constrained Lagrangian Dynamics or Newton-Euler formulation, including tyre mechanics for made pavements or terra-mechanics in off-road terrains.
The Tribodynamics Laboratory with floor area of 225 m2 comprising (main items):
- A long wheel-base light truck drive train system with programmable electric drive and IMO controller, instrumented by free-field microphones and laser vibrometry.
- A short wheel-base vehicular drive train system with automatic transmission and torque converter with programmable electric drive and IMO system, fully instrumented with free-field microphones and laser vibrometry.
- An in-house designed and developed precision slider-bearing rig for measurement of friction with sensitivity of 0.1 N, with an almost frictionless floating plate arrangement with piezo-electric load cells. There is a large supply of coated, honed and etched floating plates. The machine is mounted on a 5mX2m state of the art vibration isolation table.
- A three ball interferometric machine comprising a driven lower race and a flat horizontal cage with an upper loaded crown optical glass race through an air bearing. This arrangement includes full optical interferometric set up.
- A number of precision routing spindle bearing systems, including a 7.5 KW power demonstrator router with ceramic back-to-back bearing setting for dry machining of non-ferrous abrasive substrates. It has a maximum speed of 25000 rpm with grease lubricated bearings or 40000 rpm with lubricant recirculation cooling. This is a precision spindle with an indicative run-out of 1µm to study bearing induced vibration
Industry-standard engine 32 m2 test cell, comprising:
- Combined 4-cylinder 4-stroke diesel engine with 6-speed transmission and front transaxle final drive on a test bed with PMC ECU control, resisted by a Froude 250 KW eddy current dynamometer. Full test bed instrumentation is incorporated.
Industry-standard engine 32 m2 test cell, comprising:
- A single cylinder modified Honda motocross motor-bike CRF 450 R engine with wet barrel arrangement and large number of advanced motorsport laser textured and coated surfaces (Ni-SiC, Borided or DLC, Xylan variants), resisted by a Oswald 250 KW programmable transient dynamometer with Shenk controls. This configuration ((over 90KW/Ltr and 110Nm/Ltr) is representative of the highest performing naturally aspirated single cylinder engine technology.
- A fully in-house developed modular floating liner for direct measurement of in-cylinder friction with replaceable liner insert technology and incorporated high sensitivity piezoelectric load cells, capable of precision measurement under fired conditions up to a speed of 6000 rpm, loads of 4.5 KN and chamber pressures of 80 bar.
There are an array of precision metrological devices, including Atomic Force Microscope AFM), white light interferometry (Zygo and Alicona) as well as precision CMM.