ICRI Project: Friction Modelling


Friction Modelling

Friction Modelling

Leaders: Klaus Six, Virtual Vehicle and Edwin Vollebregt, Vtech CMCC

Description: Friction in the wheel-rail contact is an important part of this complex tribological system and therefore has a high influence on Vehicle Track Interaction (VTI). To realize high quality VTI predictions (vehicle/traction/braking dynamics, wear, damage, etc.), reliable friction models taking into account the most important tribological phenomena are of high importance. A review was made on friction modelling and the creep force characteristic, published in the journal on Vehicle System Dynamics International Journal of Vehicle Mechanics and Mobility [1]. Vtech used the model to simulate measurements on the Virginia Tech-FRA roller rig.

Status: An overview of the state-of-the-art paper was presented at the ICRI workshop in September 2022 in Melbourne, Australia. Research gaps were summarized as:

  • Further measurements are needed, to get a better grip on the “surface conditions”;
  • Detailed integrated simulation should be attempted for detailed measurement data, with a focus on identifying the creep forces involved.

In 2017-19, VORtech received research funding from the US FRA for improved modeling of creep-forces. Physics-based sub-models for temperature and solid third-body layers have been developed and implemented into CONTACT. Further, CONTACT was implemented in GENSYS, UM, NUCARS and SIMPACK, and used to simulate measurements of NRC’s full-scale wheel, brake and bearing test-rig. The final report is submitted to the FRA and is going through an editorial process.

Sheffield University & Virtual Vehicle & LBFoster received research funding of the FRA, for developing a model to predict carry down, consumption and related friction of TOR friction modifier products applied by field side application devices.  Small-scale and full-scale experiments have been carried out. Furthermore, a theoretical model has been developed which has been parameterized and validated by the experimental data. The work has been published at the TRB-2019 conference [2], the IAVSD-2019 conference [3] and in the Journal Lubricants [4]. Sheffield University & Virtual Vehicle have applied for a FRA follow-up project with the aim to enhance and implement the developed model that takes account of falling friction at higher creep levels and the effects of third-body layers resulting from the application of a range of TOR materials. The decision is pending.

Last review/developments: 04SEP22 see Presentation in Melbourne


[1] E. Vollebregt, K. Six, O. Polach, Challenges and progress in the understanding and modelling of the wheel–rail creep forces, Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility, Vol. 59:7 (2021), 1026-1068, https://doi.org/10.1080/00423114.2021.1912367

[2] K. Six, Z.S. Lee, G. Trummer, R. Lewis, Testing and modeling the effects of friction modifiers on creep forces in the wheel-rail interface, in: The Transportation Research Board (TRB) 98th Annual Meeting (2019), Washington, D.C., USA.

[3] Z.S. Lee, G. Trummer, K. Six, R. Lewis, Wheel/rail creep force model for wayside application of top of rail products incorporating carry on and consumption effects, in: 26th International Symposium on Dynamics of Vehicles on Roads and Tracks (IAVSD2019), Gothenburg, Sweden.

[4] G. Trummer, Z.S. Lee, R. Lewis, K. Six, Modelling of frictional conditions in the wheel-rail interface due to application of top-of-rail products, Lubricants, 9, 100 (2021), https://doi.org/10.3390/lubricants9100100


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