Assessment of uncertainties in life prediction of fatigue crack propagation in welded rails
Paper in proceedings, 2009
The propagation of fatigue cracks in a welded railway rail is studied for a heavy haul load case. The interaction between the welding residual stress field and the stress field caused by service loads is simulated in a nonlinear FE analysis where the welding residual stress distribution (shape) and magnitude, the service load magnitude, and the material parameters used in the fatigue life estimation are varied. A crack propagation analysis is carried out in the rail web using a Paris-type crack growth law. The accuracy in the fatigue life assessment is evaluated by statistical uncertainty analysis where the variances are calculated using the Gauss approximation formula. The fatigue crack propagation in the rail web is enhanced due to the welding residual stress and the uncertainty in load level dominates the uncertainty in the fatigue assessments.