Numerical stress analysis and rolling contact fatigue of White Etching Layer on rail steel

On the mechanism of squat formation on train rails – Part I: Origination

“…9 shows, on different scales, very typical surface crack initiations: cracks are typically found to initiate from delaminating white etching islands at the edge at the gauge side and to branch into the material following the deformed microstructure. The initiation of cracks at the edges of white etching islands is consistent with the modelling work by Seo et al [23], who found from simulations the shortest fatigue life under iterating contact loading at the starting point of a WEL, as well as accumulating residual stresses at the interface between the WEL and the base material, which could explain delamination. A second consistently found principle of crack initiation is visible in Fig.…”

The influence of high temperature due to high adhesion condition on rail damage

“…The temperature field on the rail, therefore, increases with every cycle of rolling [18] which can result in the formation of a 10-100 mm thick layer on the contact surface [30]. This layer known as white etching layer (WEL) [31] due to the white appearance after etching in Nital is brittle, and can be the spot for crack initiation. This layer is formed at about 720 1C [32] but high hydrostatic pressure reduces the temperature at which this later can form [33].…”

“…The investigation drawn a conclusion that the cracks initiated at the surface propagated rapidly within the WEL due to its brittle behaviour to the bulk material and caused the failure of the rail. Seo [31] conducted an analysis on the damage of WEL by two-dimensional (2D) FE model. The obtained results showed that the fatigue life at the end point of WEL is longer than those at the middle and starting sites.…”

A single parameter to evaluate stress state in rail head for rolling contact fatigue analysis

“…Study of the stress distribution on the white etching layer on rail head was carried out using two‐dimensional finite element model by Seo et al . . The influence of non‐steady rolling contact on the contact stresses was investigated by Wen et al .…”

“…Study of the stress distribution on the white etching layer on rail head was carried out using two-dimensional finite element model by Seo et al. 14 The influence of non-steady rolling contact on the contact stresses was investigated by Wen et al. 15 Mutton et al 1 also investigated the influence of loading conditions and increased head loss on longitudinal stresses in the rail head and the tendency for rolling contact fatigue cracks to cause rail failure.…”