Numerical Investigation into the Effect of Geometric Gap Idealisation on Wheel‐Rail Rolling Contact in Presence of Yaw Angle

Abstract

For a fast calculation of vehicle-track dynamics and wheel-rail contact mechanics, wheel-rail contact geometric gap is usually idealised in elliptic or nonelliptic form. These two idealisations deviate from the actual one if the lateral combined curvature within the contact patch is not constant or the yaw angle of wheelset exists. The influence of these idealisations on contact solution has not yet been deeply understood, and thus the accuracy of simplified contact modelling applied to vehicle-track dynamics and wheel-rail contact mechanics remains uncertain. This paper presents a numerical methodology to treat 3D wheel-rail rolling contact, in which the asymmetric geometric gap due to yaw angle is fully taken into account. The attention of this work is placed on investigating the effect of geometric gap idealisation on wheel-rail contact force, rolling contact solution, and wear distribution. It can help with the effective wheel-rail contact modelling on the computation of both vehicle-track dynamics and wheel-rail contact mechanics.

Detailed wheel/rail geometry processing using the planar contact approach

“…The software foundation was constructed in a long and tedious process, were we had to step back and make changes multiple times. For instance, we first used dimensions, positions and orientations at many places in the programme, as seems to be common in the algorithms for contact mechanics [39][40][41]45,46], but this created an unmanageable situation. This is addressed in the final design using markers, localising the specification of positions to a single routine, and isolating and shielding the formulas used for rotations.…”

“…Many works have been published on the incorporation of wheel/rail contact in vehicle dynamics, e.g. [28][29][30][31], and on the subsequent contact geometry problem [32][33][34][35][36][37][38][39][40][41]. However, these works don't deliver completely workable solutions as needed by CONTACT.…”

Applying Two Simplified Ellipse‐Based Tangential Models to Wheel‐Rail Contact Using Three Alternative Nonelliptic Adaptation Approaches: A Comparative Study

“…where is penetration; h is the undeformed distance that can be solved via a rigid geometrical method [32,33]; u(x, y) is the elastic deformation within the contact patch A c and can be obtained from half-space equation,…”

“…A further study for worn profiles will be investigated in the next work. Note that before performing a contact simulation; it should carry out a contact geometry calculation [32,33]. The input parameters for contact geometry and wheel-rail's material property are listed in Table 1.…”

“…Since the yaw angle is not enough large to change contact shape obviously, we only consider its effect on creepage. For a detailed investigation of yaw angle's role on contact shape and creepage, readers are referred to [33]. At each case, the creepage (c x and c y ) and spin ( ) are calculated by (30),…”