Authors: Lucia Pisarova, Stefan Eder, Mina Zivanov, Hendrik ehrich, Christoph wintersteiger, Shreyas Jalikop, Michal Kracalik
27th October 2026
Smarter R&D - predictions of functionality, stability, efficiency and durability
Replacing lubricant or its ingredients raises a simple question: will the alternative still do the job? Regulatory pressures, supply chain instability and evolving performance and machinery requirements drive substitution. AC2T’s modelling tools aim to inform replacement decisions by predicting the impact of changes and prioritizing promising additives, base oils, and formulations, to reduce extensive early-stage testing needs.
Continuous viscosity maps: impact on performance in application
Viscosity index describes how viscosity changes with temperature but does not capture simultaneous pressure or shear-rate effects present in the tribological contacts. Temperature, pressure and shear rate jointly influence viscosity and therefore lubricant film thickness and frictional losses. AC2T’s methodology provides insights beyond datasheet values for a wide range of operating conditions.
For known molecular compositions, molecular dynamics (MD) simulations can predict density and viscosity even under conditions that are difficult to access experimentally – high pressures and shear rates, as well as their ternary combination with temperature. For formulated products with complex, unknown compositions, combination of binary temperature-pressure and temperature-shear experimental data serve as input for modelling. AC2T’s lubricant-specific empirical viscosity models can utilize experimental and simulation data and their combination, to provide continuous viscosity evolution maps across temperature, pressure, and shear rate combinations. The continuous viscosity maps help identify which alternative lubricants are predicted to match or improve reference performance and across which operating conditions.
These predictions provide essential input to contact finite element method (FEM) models that translate lubricant rheology into application-relevant predictions of film thickness, and frictional energy losses. By considering particular contact geometry, material and surface characteristics, and application conditions, engineers can assess if sufficient surface separation is reached while trying to limit energy losses. Applying the same assessment strategy to aged lubricants reveals how performance changes relative to the fresh state. These explicit use-phase performance results further inform sustainability
assessment.
Molecular functionality: predicting surface protection and stability
Rheological behaviour is only part of the lubricant’s performance. AC2T is also developing reactive molecular dynamics (rMD) models to investigate how lubricant additives interact with surfaces and how lubricant stability changes under application-like conditions. These address two practical questions: how effectively additive protects the surface and how resistant is a base oil to degradation?
For surface-protective additives: extreme pressure and anti-wear additives, friction modifiers, and corrosion inhibitors, rMD investigates tribofilm characteristics (bonding under application-like conditions, stability, tribofilm composition), frictional behaviour as well as surfaces’ protection against water and salt in case of corrosion studies. New additive candidates can be assessed for multifunctional potential and compared to established benchmarks for objective relative ranking under defined simulation conditions. The base oil studies examine degradation due to effects of heat, oxygen, and water presence and predict products that may form. The results might be also utilized for lubricant-replacement scenarios within sustainability assessment, while degradation-product identification informs separate safety considerations.
What insights can these models provide?
- Surface-protection models: how candidate additives interact with a target surface, under which conditions tribofilm forms, multifunctional potential of an additive, and how film stability and friction compares under consistent conditions.
- Stability models: relative benchmarking of resistance to degradation under defined conditions and main degradation products formation.
Contact models: optimizations for efficiency and durability
AC2T’s finite element method (FEM) models evaluate lubricant performance within particular contact situation defined by: contact geometry, material and surface characteristics as well as applied application conditions to assess efficiency and durability over timescales beyond practical testing durations. The three FEM models represent application-representative benchmarking contacts for the project’s chemical use cases:
- four-ball contact for extreme-pressure additives in boundary lubrication for MWF;
- twin-disc contact for antiwear additives in mixed lubrication regime for gears;
- block-on-ring contact for base-oil assessment under EHL regime for journal bearing.
These FEM models provide controlled lubricant benchmarking conditions but can also serve for contact design studies.
What insights can the FEM models provide?
- Surface separation and load sharing: prediction of lubricant-film thickness and lubricant and asperity contact load sharing for proper lubricant selection per defined contact situation.
- Frictional power losses: enabling optimization of lubricant selection to minimize frictional losses under defined contact situation.
- Wear evolution: wear-volume assessment to predict durability scenarios affected by lubricant type and operating conditions per defined contact situation.
Connecting performance to sustainability
FEM results supply use-phase evidence for sustainability assessment purpose. Frictional power losses can inform energy-demand calculations over a defined operating scenario, while wear estimates can inform component-replacement scenarios.
Turning connected modelling into industrial value
Different industry stakeholders need different insights—not the same sequence of simulations. SiToLub toolbox can flexibly create workflows around the user question, available data and model applicability to support additives and base oils ranking, formulation benchmarking and application-level like assessment. The practical benefit is a clearer basis for deciding which alternatives deserve testing, which performance trade-offs matter and what evidence is still missing prior more-targeted R&D. The capabilities are relevant for e.g., regulatory driven substitutions, emerging applications, efficiency improvement needs, and responses to price or supply-chain disruptions.
- Additive manufacturers — prioritize functional alternatives.
Compare surface protection, friction, and multifunctional potential against benchmarks under consistent conditions. Shortlist promising chemistries for testing.
- Base oil manufacturers and refiners — differentiate beyond viscosity grades.
Compare viscosity across temperature, pressure and shear rate, alongside degradation impacts, to prioritize base oils for specific contact situations.
- Lubricant formulators — benchmark products and focus reformulation.
Select ingredients for targeted trials focusing on testing the most promising candidates and benchmark formulations under consistent application-like conditions. Compare film thickness, load sharing and frictional losses and wear across lubricant, contact and operating conditions to balance reliable surface separation with frictional losses and durability.
- OEMs — co-design equipment and lubricant requirements.
Compare alternatives against the same requirements, use rheological and contact models to explore lubricant–component combinations during equipment development. Investigate how changes in geometry, materials, surface characteristics, and operating conditions influence performance.
- Sustainability and product-stewardship teams — connect impacts with function.
Use energy-loss, wear and stability evidence to compare life-cycle scenarios for energy demand, component replacement, and lubricant consumption against the same delivered function. This helps identify trade-offs, prioritize alternatives, and target missing evidence rather than judging sustainability from composition alone.
