UIC60 rail alumino thermite weld’s semi elliptical head crack and stress intensity factor using ANSYS

Abstract

In railway track the rail and its weldment are generally working under a load kind of a complex or mix mode nature, which causes stresses and deformations in the material inside it, resulting in rolling contact fatigue. Due to fatigue, cracks in the ductile material of the rail and its weldment at the surface level are possible. In most cases, a semi-elliptical form of crack appears on the rail's surface or in its weldment. Assuming a semi-elliptical crack having major axis normal to axis of weldment with minor axis parallel to the rail weld depth the SIF (Stress Intensity Factor) is estimated by using frictional contact and tractive effort with vertical load only and neglecting lateral load conditions under dynamic action with variable vehicle speed. ANSYS 2020 student edition is used to do a three-dimensional finite element study on rail wheel contact on the weld. For the model simulation, the most commonly used parameters adopted by the Indian Railways for rolling stock are the UIC60 type of rail profile cross section and a general wheel size of 1150 mm diameter with axle has been chosen for analysis. Then, for a semi-elliptical crack, the results and graph, with the crack simulation pictorial view acquired with ANSYS, are plotted and analyzed, taking into account the values of coefficient of friction and variable train speed. The Stress Intensity Factor is estimated to its highest value at the deep most point of the crack front, and Tada, Paris, and Ervin's Stress Intensity Factor calculation approach provides results that are similar to those observed in simulation.