The local strain energy density approach applied to pre-stressed components subjected to cyclic load

Ahead of sharp V-notches, residual stresses, arising from the solidification of a fusion zone, have the same asymptotic nature of the stress field induced by mechanical loads. This stress field significantly affects the engineering properties of structural components, notably fatigue life and corrosion resistance of welded joints. Tensile residual stresses can reduce the fatigue strength of welded joints particularly in the high-cycle regime, where no stress redistribution due to local plasticity phenomena is expected to be present. The aim of this work is to analyse, by means of the numerical simulation, the residual stress redistribution near a V-notch tip induced by cyclic loads and to propose a method, based on the local strain energy approach, for the fatigue resistance estimation of pre-stressed components. The numerical solutions of the problem were carried out under the hypothesis of generalized plane strain conditions by means of SYSWELD and SYSTUS codes.