ResearchActivities

Wheel-rail interface as an open tribology system

Abstract:
This research and development focus on advancing the digitalisation of rail transport through the simulation tools and models that predict adhesion conditions between wheel and rail, implementing them into the digital twin concept. The aim is to optimise the operation and maintenance planning of rolling stock by assessing the state of the interface between the track and the rolling stock.

Main objectives:

  • To clarify the mechanisms of very low adhesion between wheel and rail.

  • To develop predictive models for wheel-rail friction within an open tribological system.

  • To develop prediction algorithms and diagnostic tools applicable in the context of the digital twin.

Research content:
The wheel-rail interface is a complex open tribological system that is highly influenced by external conditions, resulting in a wide range of friction coefficients on the rail surface (0.01 to 0.5). Low friction conditions are particularly problematic, often causing issues with the starting and braking rail vehicles. These conditions are caused by the natural contamination of the contact area by water, biological materials like leaves, and solid particles such as dust, oxides, and wear particles. The research, among other things, aims to experimentally clarify the mechanisms behind these sudden drops in friction, which are crucial for maintaining safe and efficient rail operations. Recent findings suggest that friction drops are associated with the transitional behaviour of solid particle suspensions as water evaporates from the contact area. Additionally, the effects of leaf contamination combined with moisture and he presence of naturally occurring oxide layers are challenging to predict.

The outcomes of this research provide the foundation for algorithms that enhance the accuracy of predicting adhesion conditions between wheel and rail implemented within the digital twin concept. The digital twin acts as a virtual representation of machine, device, or process, allowing for the determination or prediction of its parts and overall system state based on real-time operational data. In rail transport, this concept is increasingly applied across various subsystems, particularly in asset management and the operation of rolling stock, including autonomous vehicles.

Publications:
GALAS, R.; OMASTA, M.; SHI, L.; DING, H.; WANG, W.; HARTL, M.; KŘUPKA, I. The low adhesion problem: The effect of environmental conditions on adhesion in rolling-sliding contact. Tribology International, 2020, vol. 151, no. 11, p. 106521-106531. ISSN: 0301-679X. https://doi.org/10.1016/j.triboint.2020.106521

KVARDA, Daniel, et al. Testing and modelling of transient adhesion phenomena in rolling-sliding contacts. Friction 2024, 12, s. 1016-1027. https://doi.org/10.1007/s40544-023-0825-8

SKURKA, Š.; GALAS, R.; OMASTA, M.; WU, B.; DING, H.; WANG, W.; KŘUPKA, I.; HARTL, M. The performance of top-of-rail products under water contamination. Tribology International, 2023, vol. 188, no. Říjen, p. 108872-108872. ISSN: 0301-679X. https://doi.org/10.1016/j.triboint.2023.108872

Partners and Collaboration:
Virtual Vehicle Research GmbH, Inffeldgasse 21a, 8010 Graz, Austria.

ŠKODA TRANSPORTATION a.s., Emila Škody 2922/1, Jižní Předměstí, 301 00 Plzeň, Czech Republic.


Projects:
Božek Vehicle Engineering National Center of Competence (BOVENAC), Technology Agency of the Czech Republic (TA CR) – National Centres of Competence, TN02000054, 2023-2028.

Friction phenomena in rolling contacts caused by suspensions, Czech Science Foundation, LA grant , 24-14624L, 2024-2026.

Contact person:
Ing. Milan Omasta, Ph.D.