Fatigue life assessment of railway rail subjected to welding residual and contact stresses

Even though repair welding has been adopted as a useful remedial technique for railway rail, cracks were found beneath the weld layer under wheel-to-rail contact conditions. In the present study, lifetime assessment of a typical railway rail subjected to both welding residual and contact stresses is carried out to resolve this issue; A finite element method to predict the residual stress was established by taking into account the in-situ overlay welding process and applied for the rail with different welding depths to examine optimum weld geometry as well as failure causes. Subsequently, the contact stress during a wheel rolled over the weld was calculated and combined with the residual stress for fatigue damage assessment. The residual stress was reduced as the increase of the welding depth so that sufficient grinding before the overlay process will be beneficial to prevent unanticipated failure and the combined stress should be considered for accurate fatigue life assessment of the overlay-welded railway rail.