《rail welding》.pdf

Engineering Fracture Mechanics 72 (2005) 271–285 /locate/engfracmech Fatigue crack growth in a welded rail under the influence of residual stresses A. Skyttebol *, B.L. Josefson, J.W. Ringsberg Department of Applied Mechanics, Chalmers University of Technology, SE-412 96 Go€teborg, Sweden Received 17 June 2003; received in revised form 24 October 2003; accepted 31 October 2003 Abstract The effect of welding residual stresses on fatigue crack growth in rail welds is studied. Finite element analysis is used to calculate residual stresses in a flash-butt welded rail. The calculated residual stresses are found to be in good agreement with experimentally determined residual stresses in a welded rail. The redistribution of residual stresses in the welded rail is simulated for a straight track, during heavy-haul operation conditions, using a train–track model. Fatigue crack growth of defects in the weld region is studied using fracture mechanics. In the investigation, a number of parameters such as the axle load, crack location, crack size and rail temperature are varied. 2004 Elsevier Ltd. All rights reserved. Keywords: Rails; Flash-butt welding; Residual stresses; Fatigue; Crack propagation 1. Introduction Railway rails are manufactured in sections of 25–120 m length. The method of joining rails has changed over the years. Earlier, the most common method was to use bolting. It was, however, found that bolted joints were a large source of maintenance, and that they often broke in the plate, rail ends, or in the bolt as reported by e.g., Sih [1] and Mayville [2]. As a consequence, new joining methods for rails were investigated, and in the 1950’s, the first