A comparative study between FEA, trepanning and neutron strain diffraction on residual stresses in flash-butt welded rails

This paper compares three independentmethods for deriving the residual stresses distribution inAS60 normal cooled flash-butt welded rail. A numerical technique utilised a sequentially coupled thermo-mechanical analysis with representative temperature dependent and phase transformation properties of the rail steel. The numerical model also incorporated an element removal regime to assess the effect of stress relaxation when slicing a plate section from a welded rail section for neutron stress mapping. Two experimental techniques were used to quantify themagnitude of residual stresses in theweld; thesewere strain gauging and trepanning, and neutron diffraction (ND). The results showed satisfactory correlation between the residual stress distribution obtained from the numerical analysis and the strain gauge/trepanning data and ND stress mapping, respectively.TheNDand numerical analysis both confirmed that the tensile residual stresses in both vertical and longitudinal directions are concentrated in the web region, despite a significant relaxation as a result of the sectioning method used to obtain the plate section for neutron stress mapping.