Abstract
Wheel-rail contact in railway engineering is an important topic. Due to different materials and surface roughness of wheel and rail, the contact characteristics can alter significantly. This article aims to investigate the effects of surface roughness and asperities on the contact parameters such as contact area, contact force, and contact stiffness. The lateral contacts between asperities are assumed to be the general contact condition. Azimuthal and contact angles distributions are assumed to be spherical harmonic distribution. This assumption is compatible with the asperity distribution on the wheel and the rail surfaces. Besides, a new combined model is developed to cover the stick-slip and the plasticity effects in contacting asperities. The results of the presented model offer very good estimations for the asperities contact characteristics, especially at the small-contact area and separation where high-contact pressure and plastic deformation usually exist.
Highlights
A MATLAB program is employed to assess the outcomes of the suggested theoretical model to determine the contact problem of the rough surfaces considering asperities effects. e rough surfaces’ properties assume to be constant, and the contact properties like the contact stiffness, which is very important in many applied problems such as wheel and rail interaction, are studied
Whenever the surface parameter σ lessens, the contact force decreases with a higher rate. is fact shows that, in the smooth surfaces, the contact force reduces at a higher rate in comparison to a rough one with rising separation, which is logical since the figures of asperities in contact on a smooth surface decrease at a higher rate than a rough one
The effects of the surface asperities on the contact force, contact area, and contact stiffness are studied. e lateral contact between asperities is assumed to be the general condition for contacting surfaces. e Gao model is used for the fundamental of formulations, and corrections for the elastic-plastic contact zone, fictitious asperity theory, and slip-stick effects are carried out
Summary
Contact of surfaces is a high-risk matter from the damage initiation point of view in engineering problems and the railway industry. To develop the accuracy of the contact modeling, the topography classification of the surfaces is a real need. To this end, probabilistic models are presented to describe the contact characteristics like contact load, contact area, separation of surfaces, and contact stiffness. To improve the modeling of contacting rough surfaces, the effects of the asperities should be taken into account. In this regard, the following applied models are introduced
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