Investigation of the dynamic contact filter effect in vertical wheel/rail interaction using a 2D and a 3D non-Hertzian contact model

Rolling noise is excited by the roughness of the wheel/rail running surfaces. The contact patch acts as a filter attenuating the excitation at wavelengths that are short in comparison with its length. Additionally, the excitation depends on the variations in roughness profile height across the width of the contact. While most available wheel/rail interaction models include the contact filter effect by roughness pre-processing, a time-domain model is presented in this paper that includes the contact filter effect dynamically by an appropriate two-dimensional (2D) or three-dimensional (3D) non-Hertzian contact model. The 2D contact model is based on a Winkler bedding, while wheel and rail are locally approximated by elastic half-spaces in the 3D contact model. The wheel/rail interaction model is applied to evaluate the contact filter effect for different sets of roughness data measured in several parallel lines. It is found that the 3D contact model gives, as a general tendency, a contact force level several dB lower than the 2D model. The differences increase with a decrease in correlation between the roughness on parallel lines and vary significantly with the choice of roughness line in the 2D model.