FOR 5962:  Multiscale modelling of tribological boundary layer formation

• Subject Area: Materials Science and Engineering ; Mechanical and Industrial Engineering
• Term: since 2026
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 556252784

The service life of machine elements is largely determined by friction and wear processes. Uncertainties in the calculation of the wear service life lead to high costs for component replacements, repairs and availability. In Germany, unplanned failures of machine elements cause economic damage of around 5% of the gross national product (Czichos et al., 2015). It is known that the wear of machine elements can be effectively reduced with the aid of tribological boundary layers (< 100 nm thick) on the contact surfaces. Current research results show that these boundary layers can be produced reproducibly with very little and in some cases even without lubricant additives. In preliminary work, the applicants were able to show that extremely wear-resistant reaction layers are formed in just a few minutes, which can guarantee long-lasting wear protection (Burghardt, 2018; Burghardt et al., 2015; Stratmann et al., 2013).The processes that lead to the formation as well as the effects of these wear-reducing tribological boundary layers are not well understood. Hence, the fundamental understanding still hinders a systematic, industrial utilization of the enormous wear protection potential.The aim of the research group is to investigate a cross-disciplinary and multiscale method to describe the formation of wear-reducing tribological boundary layers on machine elements using closed experimental and simulative model chains. The relevant physical and chemical processes are investigated at the atomic level both experimentally through layer synthesis by means of deposition from the gas phase and through molecular dynamic simulations. Only this transition to the atomic level makes it possible to investigate the formation and effect of the reaction layers fundamentally and comprehensively. The knowledge gained is then to be transferred back from the atomic level to the operation and production of the machine elements by means of multiscale modelling. The intended result of this simulative model chain is an operating point-dependent prognosis of wear protection for a specific machine element. With this knowledge, machine elements and lubricants are to be designed in such a way that wear damage during operation is systematically reduced or avoided right from the design stage. The generalizability of the methodology is being sought and will be implemented in the second phase of the research group.

• DFG Programme: Research Units

Projects

• Chemical composition of the boundary layer (Applicant Hans, Marcus )
• Coordination Funds (Applicant Jacobs, Georg )
• Influence of the shear force on the formation of the outer boundary layer (Applicant Dienwiebel, Martin )
• Modelling and synthesis of adsorption and reaction layers (Applicants Dronskowski, Richard ;  Schneider, Ph.D., Jochen M. )
• Multiscale simulation to predict reaction layer formation (Applicant Jacobs, Georg )
• Thermo-mechanical formation mechanisms of the reaction layer in single asperity contacts (Applicant Dehm, Gerhard )
• Transient formation of reaction layer in non-slip rolling contacts (Applicants Brands, Thorsten ;  Jacobs, Georg )
• Zinc dialkyldithiophosphate reaction layers: atomistic understanding of the mechanochemical processes that form the layers (Applicant Moseler, Michael )

• Spokesperson: Professor Dr.-Ing. Georg Jacobs