Knowledge

Some original and hugely important bio tribology research using the HFR rig to study both friction and wear of hip implant materials in the presence of synovial fluid. The importance of proteins in determining wear of CoCrMo (Cobalt Chromium Molybdenum) couples is clearly shown with excellent repeatability.
Open Access Link:
https://www.sciencedirect.com/science/article/pii/S2352573817300677?via%3Dihub

White etch cracking is an increasingly common failure mode associated with wind turbine bearings and gears. Although a myriad of factors can cause in service failure modes and it is clear that a single parameter can be attributed to such complex defects, experimental data from the MPR points to the specific stress history of the contact being of paramount importance.

Open Access Link:
https://www.sciencedirect.com/science/article/pii/S0142112318304328?via%3Dihub

A very detailed paper on a hugely important subject, tribofilm formation and activation. The term “mechanochemsity” ( the concept of using mechanical force to initiate chemical reactions ) aptly describes this research area, which intriguingly concludes that the shear stress experienced by lubricants primarily controls the rate of additive film formation. The paper presents clear MTM mapper experimental data which is then used to discuss, in depth why and when lubricant additive films form.
Open Access Link:
https://link.springer.com/article/10.1007/s11249-020-1281-5

Some outstanding grease research carried out by a team of great experimentalists using both the MTM and EHD rigs. The novel methodology employed showed how it is possible to disentangle the behaviour of the grease thickener from that of the base oil, which is then used to explain the characteristic “bump” observed in some grease Stribeck curves. The illuminating research concludes that greases exhibit two distinct operating regions, in terms of friction and film thickness. A must read for anyone involved in this sometimes challenging area of tribology research.

Open Access Link:
https://www.sciencedirect.com/science/article/pii/S0301679X15004612

Although sometimes presented as a seemingly random and somewhat unpredictable sequence of events, this paper shows a high level of details and understanding of the mechanisms involved. A detailed introduction to micropitting is leads on to discussion and presentation of an excellent modelling technique. Predictions made by the model are compared to actual micropitting results, and pleasingly, are able to accurately predict the degree of micropitting. The paper is more of a 3 course meal than a light lunch, so pull up a chair and enjoy a large serving of micropitting knowledge!

Open Access Link:
https://www.sciencedirect.com/science/article/pii/S0043164817309535

Fundamental and extensive MTM research carried out on a wide range of well-defined fluids comparing the EHD friction properties over different contact conditions. The study confirmed crucial role the molecular structure of the base fluid plays in determining the increasingly important EHD friction coefficient.

Open Access Link:
https://link.springer.com/content/pdf/10.1007/s11249-016-0791-7.pdf

This paper provides new understanding of the tribological mechanisms that drive the occurrence of micropitting damage. EHD film thickness measurements were clearly able to show that increased micropitting damage resulting from higher slide roll ratios was not caused by a significant reduction if lubricant film thickness, questioning many of the assumptions currently being made to assess and predict micropitting damage in gears.

Open Access Link:
https://link.springer.com/content/pdf/10.1007/s11249-019-1174-7.pdf

Using the unique features of the USV, researchers were able to clearly quantify the permanent shear thinning of high molecular weight polymer solutions.  Further investigations using a standard GPC process (gel permeation chromatography) revealed that the polymer breakdown process is very different at low and high polymer concentrations. The paper finally put to rest the argument whether it is the applied shear rate or shear stress which determines shear thinning (spoiler alert: it’s the shear stress).

Open Access Link:
https://link.springer.com/content/pdf/10.1007/s11249-017-0888-7.pdf

Cutting edge MTM nanoparticle research carried out at the highly respected Carpick laboratory. The paper showed how relatively large nanoparticle of Zirconium dioxide (ZrO2), combined with organic capping ligands can form robust tribofilms under a wide range of contact conditions. Impressively significant   wear reduction was also reported when the nanoparticles were blended in commercial formulations.

Open Access Link:
https://link.springer.com/article/10.1007%2Fs11249-020-01346-1