Analysis of Residual Stress Distribution in the ESCO Rail Profile 60E1 by Contour Method

The residual stresses have an undeniable effect on the fatigue life, fatigue crack growth rate and fracture toughness of the rails. The aim of this research was study the longitudinal residual stresses in the rail profile 60E1 cross-section by the contour method. To this aim, a sample of the rail profile 60E1 having a length of 0.5m was taken from 3m of the rail end. The cutting process of the contour method was performed by wire electro discharge machining (EDM), skim cut settings, using 250μm diameter brass wire and cutting rate of 40 mm2/min. The contour of both sides of the sample after the cut was measured in ~10000 point in each side by using the mechanical contact coordinate measuring machine (CMM). To minimize the multiple possible error sources, the average of two contours was considered. The surface contour was smoothed by MATLAB software and using the bivariate fourth grade spline. The peak-to-valley amplitude of the displacement contour was about 100μm. FE analyze of the contour method was performed by ABAQUS package. The cutting plane was modeled as a flat surface and the measured contour was introduced to the node locations as displacement boundary conditions. The results present the C-shape pattern of the longitudinal residual stresses across the rail cross-section which is in good agreement with the previous results in this field. The magnitude of the residual stresses in the head, web and foot were about 180, -100 and 160 MPa respectively. The uncertainty of the results is less than ±15%.

Analysis of Residual Stress Distribution in the ESCO Rail Profile 60E1 by Contour Method Keywords:

residual stress , rail , contour method.