Tribo-Acoustic Sensors

The Leonardo Centre is the home of ultrasonic sensors for the measurement of tribological contacts. For over two decades we have been developing unique methods to measure parameters in tribological contacts both in the lab and in field applications.

Robin Mills and cylinder liner

This is a unique aspect of the research expertise in the Leonardo Centre. We pioneered the use of ultrasound to measure the thickness of oil films in machine element contacts. The key feature is that this can be done by mounting sensors on the outside of a component, sending sound waves thorough the component and bouncing back from the contact zone. We use this to measure oil film thickness, contact area and asperity contact, friction, surface films, and oil film viscosity.

Our Expertise and Activities

  • We are the world leader in the measurement of interfaces and machine elements in tribology. We have built models describing how sound waves interacts with dry, lubricated, and mixed contacts and use these to interpret reflected ultrasonic signals.
  • We have expertise in range of ultrasonic techies including bulk longitudinal and shear waves, surface waves, and non-linear ultrasound. All of these have unique features that can help us measure tribological phenomena.

  • We have worked with many industrial companies to instrument their components in lab or field applications. This has included face seals, rolling bearings, thrust pads and tilting pad bearings, wind turbine bearings, metal ring rollers, con-rod and crankshaft bearings, piston rings and liners.

  • Our work spans automotive, railway, energy, marine, aerospace and manufacturing sectors. In fact there are few tribological components that we have not measured at some point.

  • Prof Dwyer-Joyce holds an EPSRC Advanced Career Fellowship in the field of Tribo-Acoustic Sensors.

Current and Past Research Projects

  • Evaluation of Environmentally Acceptable Lubricants, EALs for marine stern tube bearings.

  • Ultrasonic sensors for wind turbine bearing load and lubrication monitoring; measuring direct roller/race contact loads, and residual oil film in bearings.

  • In-situ viscometry of oil in a contact; effects of high shear and high pressure.

  • Measurement of piston ring lubrication film thickness in marine diesel engines.

  • Multiple echo standing waves to measure very thin films and coatings.

  • State of Charge and State of Health assessment in Lithium-Ion batteries using reflected and transmitted ultrasound.

  • The use of non-linear response to high power ultrasound to measure friction and slip at the interface.

  • Ultrasonic sensors in metal rolling to measure fluid film thickness, roller stress, strip thickness, and shear on a lab and factory based pilot mills.

  • Longitudinal stress and wheel/rail contact area determination using ultrasonic methods.

  • Oil film thickness measurement in automotive crank-shaft and corned bearings in motored and fired engines.


Prof Rob Dwyer-Joyce,

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