Development of physics-based models for predicting the lubricant film thickness in grease-lubricated rolling contacts under starvation

• Applicant: Professor Dr.-Ing. Georg Jacobs
• Subject Area: Engineering Design, Machine Elements, Product Development
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 564003104

The tribological behavior of individual machine elements, such as rolling bearings, is critical to the reliability and efficiency of mechanical systems. Therefore, design efforts are made to minimize friction and wear in tribological contacts, such as rolling elements and raceways, by separating the contacting surfaces through a lubricant film. If the oil quantity is unlimited, the thickness of this lubricant film, and thus the degree of surface separation, can be reliably calculated with currently available models. In grease-lubricated applications, however, the amount of oil available due to bleeding is limited and starvation can occur. During operation under starvation, the lubricant film thickness decreases and solid contact between roughness peaks is possible. This results in increased friction and material stresses and endangers a reliable, energy-efficient operation. An exact prediction of the lubricating film thickness is not possible with the known models. This knowledge gap will be closed in the planned project through the development of physics-based models for predicting the lubricant film thickness in grease-lubricated rolling contacts under starved conditions. In addition to a more reliable design, the models developed can be used to select a resource-saving minimum quantity grease lubrication for energy-efficient and reliable machine operation.

• DFG Programme: Research Grants
• Co-Investigator: Dr.-Ing. Florian König