Application of Non-Hertzian Creep Force Models in Rail Vehicle Dynamics Simulation

In this paper, two commonly used creep force algorithms in rail vehicle dynamics simulation, namely FASTSIM and Shen-Hedrick-Elkins, are extended to solve non-Hertzian wheel/rail contact problems based on the SDEC regularisation of non-Hertzian contact patches. The extended algorithms for non-Hertzian conditions have been implemented as user routines in Simpack which enables the assessment of the influence of the extended force models on the rail vehicle dynamics through comparison to the traditional Hertzian models in the same environment. To this end, a single wheelset and a complete rail vehicle model are selected as case studies to demonstrate the application of the developed non-Hertzian creep force models in rail vehicle dynamics simulations, and its impact is studied by comparative analysis of the simulation results obtained from using both Hertzian and non-Hertzian models. The results suggest that the Hertzian and non-Hertzian creep force models result in different dynamic behaviours of the system and the level of difference can be significant in a certain context which may cause different conclusions on the assessment of the system, for instance in view of vehicle homologation.