Modelling of wear and fatigue defect formation in wheel–rail contact

Abstract

The model for analysing wear and fatigue defect formation is developed based on the approaches of contact and fracture mechanics. The model includes the solution of the contact problem for the wheel and rail to find the shape, size and position of the contact zones and the contact stresses and calculation of the surface wear and the function of damage accumulation in the rail and wheel. The wear rate and the worn-profile evolution of the wheel surface are calculated using both statistic and deterministic approaches to modelling of vehicle dynamics (tribo-dynamic modelling). The influence of the evolution of the wheel–rail profiles due to wear on the damage accumulation process is analysed. It is shown that for some values of the wear rate coefficient, the wear process can prevent the crack initiation under the wheel surface.

Keywords:

• wear
• tribo-dynamic modelling
• contact mechanics
• wheel–rail interaction
• fatigue
• wheel profile
• rail profile

Acknowledgements

This work was financially supported by the Russian Foundation for Basic Research (grants 09-08-00901-à and 09-08-01236-à) and by the grant of state support of science research of the chief science schools (SS-3288.2008.1).

Notes

Profiles differ from each other by the conicity of the tread, fillet radius and flange thickness. Zinuk-Nikitskij and DMetI profiles have increased conicity and are in use only on locomotives and passenger cars.

Locomotive VL10U has an axle formula Bo-Bo – Bo-Bo with the axle load 230 kN. This wide-boarded locomotive in Russia has lead diagonal axle-boxes and pendulum suspension of bogies. The base of the bogie (the distance between axles of one bogie) is 3 m and the base of the vehicle (distance between bogie centres) is 7.5 m.