Computational methods to predict RCF crack initiation hot spots in rails using critical plane SWT damage indicator parameter
Rolling contact fatigue (RCF) crack initiation in rails remains a critical failure mode under increasing axle loads and line capacities. Existing predictive methods struggle to capture the combined influence of fluctuating creepage, contact positions, and load spectra on crack location and orientation. This study proposes a computational framework integrating multi-body simulations (MBS), finite element analysis (FEA), and critical plane approaches. A novel multi-variable sampling technique reduces complex loading spectra into representative traction profiles, which are then analyzed using the Smith–Watson–Topper damage indicator parameter (DIPSWT). The maximum DIPSWT identifies the critical plane and potential crack orientation. A case study on the Swedish heavy haul line Malmbanan, specifically a 384 m section of a R=450 m curve, incorporates measured traffic and loading conditions. Results show the highest DIPSWT for the locomotive with loaded payload configuration, reaching a cumulative maximum of 3.84×10−8 at 38.59 mm from the lower gauge face corner. The DIPSWT critical plane orientation (35–37° to rolling direction, 33–44° to rail surface) aligns with experimental measurements of RCF cracks near the gauge corner. This method enables efficient identification of RCF-prone conditions and crack orientations, complementing existing predictive tools.