Green Tribology

From wind turbines to electric cars, green industries are growing rapidly. Using our instruments, tribologists around the world are helping to improve the efficiency and reliability needed to make these industries viable.

In renewable power, efficiency and reliability are key. Take wind power as an example and you find that the profit margins over the life of a turbine are narrow due to high setup costs, and the huge costs associated with maintenance, downtime, and repairs. Reliability is therefore key in ensuring wind power remains a viable power source for the future. Tribology plays a critical role in this as common failure mechanisms in wind turbines such as excess wear, micro and macro pitting, false brinelling and cracking can all be investigated using instruments from PCS.

Efficiency and reliability are just as important in other industries, such as the electric car market. Currently one of the hurdles facing the mass uptake of electric cars is their range and cost. One way to solve both these issues is improving efficiency, something currently being worked on by tribologists around the world. Improving drivetrain efficiency would mean electric cars would need fewer batteries to go the same distance – thus cutting costs – or you could keep the same number of batteries but go further for the same cost.

PCS Instruments is giving tribologists the tools to develop new and improved fuels, lubricants and additives, are helping to solve the multitude of problems green industries are facing, and ultimately fight climate change.

Green Tribology research areas include:

  • Marine specific lubricants that are safer for sea life
  • Bio-lubricants and fuels that are sustainable
  • Development of improved wind turbine gearbox oils
  • New grease designs for electric vehicles
  • Optimisation of lubricants for improved efficiency in systems

Green Tribology Industry includes the following:

Bio Lubricants

Bio Lubricants

Improving the performance of new, more environmentally friendly lubricants. Developing them to perform as well as, or better than traditional lubricants.

Electric Vehicles

Electric Vehicles

With governments pushing for more electric vehicles, this field of research is growing faster than ever and the new challenges it brings are being met head on, with tribology holding many of the answers.

Renewables

Renewables

One area of tribological research for renewables is their feel. As an often cited reason for why someone doesn't want to switch products, finding ways to develop new renewable products with the same feel is critical.

Wind Turbines

Wind Turbines

Wind power remains one of the most rapidly growing renewable power sources, so the tribological problems found in the gearbox, bearings and generator are the focus of significant research.

Instruments for the Green Tribology Industry

Speak to us about our products

Get in touch

Green Tribology Industry Articles & Papers

Paper

In-situ Observations of the Effect of the ZDDP Tribofilm Growth on Micropitting

The ongoing trend for using ever lower viscosities of lubricating oils, with the aim of improving the efficiency of mechanical …

The ongoing trend for using ever lower viscosities of lubricating oils, with the aim of improving the efficiency of mechanical systems, means that machine components are required to operate for longer periods under thin film, mixed lubrication conditions where the risk of surface damage is increased. For this reason, the role of zinc dialkyldithiophosphate (ZDDP) antiwear lubricant additive has become increasingly important in order to provide adequate surface protection. It is known that due to its exceptional effectiveness in reducing surface wear, ZDDP may promote micropitting by preventing adequate running-in of the contacting surfaces. However, the relationship between ZDDP tribofilm growth rate and the evolution of micropitting has not been directly demonstrated. To address this, we report the development of a novel technique using MTM-SLIM to obtain micropitting and observe ZDDP tribofilm growth in parallel throughout a test. This is then applied to investigate the effect of ZDDP concentration and type on micropitting. It is found that oils with higher ZDDP concentrations produce more micropitting but less surface wear and that, at a given concentration, a mixed primary-secondary ZDDP results in more severe micropitting than a primary ZDDP. Too rapid formation of a thick antiwear tribofilm early in the test serves to prevent adequate running-in of sliding parts, which subsequently leads to higher asperity stresses and more asperity stress cycles and consequently more micropitting. Therefore, any adverse effects of ZDDP on micropitting and surface fatigue in general are mechanical in nature and can be accounted for through ZDDP's influence on running-in and resulting asperity stress history. The observed correlation between antiwear film formation rate and micropitting should help in the design of oil formulations that extend component lifetime by controlling both wear and micropitting damage.

View abstract

Paper

Prediction of Micropitting Damage in Gear Teeth Contacts Considering the Concurrent Effects of Surface Fatigue and Mild Wear

The present paper studies the occurrence of micropitting damage in gear teeth contacts. An existing general micropitting model, which accounts …

The present paper studies the occurrence of micropitting damage in gear teeth contacts. An existing general micropitting model, which accounts for mixed lubrication conditions, stress history, and fatigue damage accumulation, is adapted here to deal with transient contact conditions that exist during meshing of gear teeth. The model considers the concurrent effects of surface fatigue and mild wear on the evolution of tooth surface roughness and therefore captures the complexities of damage accumulation on tooth flanks in a more realistic manner than hitherto possible. Applicability of the model to gear contact conditions is first confirmed by comparing its predictions to relevant experiments carried out on a triple-disc contact fatigue rig. Application of the model to a pair of meshing spur gears shows that under low specific oil film thickness conditions, the continuous competition between surface fatigue and mild wear determines the overall level as well as the distribution of micropitting damage along the tooth flanks. The outcome of this competition in terms of the final damage level is dependent on contact sliding speed, pressure and specific film thickness. In general, with no surface wear, micropitting damage increases with decreasing film thickness as may be expected, but when some wear is present micropitting damage may reduce as film thickness is lowered to the point where wear takes over and removes the asperity peaks and hence reduces asperity interactions. Similarly, when wear is negligible, increased sliding can increase the level of micropitting by increasing the number of asperity stress cycles, but when wear is present, an increase in sliding may lead to a reduction in micropitting due to faster removal of asperity peaks. The results suggest that an ideal situation in terms of surface damage prevention is that in which some mild wear at the start of gear pair operation adequately wears-in the tooth surfaces, thus reducing subsequent micropitting, followed by zero or negligible wear for the rest of the gear pair life. The complexities of the interaction between the contact conditions, wear and surface fatigue, as evident in the present results, mean that a full treatment of gear micropitting requires a numerical model along the lines of that applied here, and that use of overly simplified criteria may lead to misleading predictions.

View abstract