Reconstruction and Modeling Method for Rail Head Checks in Heavy-Haul Railways Based on X-Ray Computed Tomography and the Extended Finite Element Method

To understand the characteristics of head check (HC) propagation, the methods for reconstruction and modelling HCs in the rail were presented by realizing the geometry morphology and spatial position of HCs with the help of some creative technologies: X-ray computed tomography (CT) was applied to detect the rail specimens taken from a curve in a heavy-haul railway and the three dimensional (3D) internal information of HC was extracted and digitalized to the point cloud data with 3D coordinate by thresholding of the grey level. For splicing HCs in different rail specimens, removing the abnormal points, extracting and fitting the edges of HCs, the algorithms for investigating the geometry characteristics, including geometry morphology and spatial angle were designed and programmed. Therefore, the reconstruction of 3D HCs in rail was realized by reconfiguration of geometry morphology and spatial position. By defining the contact property, the fitted 3D HCs were assembled and coupled with a 3D rail model for further crack propagation analysis with the eXtended finite element method (XFEM). The reconstruction results can provide an accurate method for reconstruct HC and a reliable model for study the HCs propagation in the rails of the heavy-haul railway.