3D stress intensity factor evaluation of subsurface cracks in a railway curve

Abstract

Curved tracks and certain conditions may result in two-point contact, in which the rail experiences a multiaxial stress state. The initiation and propagation of subsurface cracks follow this. Studying these cracks is crucial for railway safety. In this work, a validated finite element model of the rail and wheel, developed using the weight function method and half-space modeling, is applied to study the three modes of stress intensity factors (SIFs). The equivalent SIF is also extracted to assess 3D subsurface elliptical cracks. The principle of LEFM is applied to obtain the variation of SIFs of subsurface cracks along their fronts. In the rail, three areas have been selected for analysis. Two of these areas are located in the head, and one is located in the web of the rail. The objective of this study is twofold. First, the SIFs of subsurface cracks will be assessed under two-point contact conditions. Second, the lateral load resulting from the effect of passage in a curve, in conjunction with a vertical load, will be examined. Different subsurface crack arrangements and angles are compared to determine the critical state. The outcomes indicated that 45-degree and horizontal cracks have higher stress intensity factors. In the gauge area, the nearly horizontal subsurface crack exhibits the largest equivalent stress intensity factor compared to all other conditions. This makes the zone more susceptible to failure in the curved tracks.