Fatigue Life of Repaired Welded Tubular Joints

In this study, the effect of repair on fatigue life of tubular joints is investigated. Six cracked specimens precedently subjected to fatigue loading undergone to weld repair. Two of those specimens were shot peened before primary fatigue loading.  It is shown that repair gives rise to about 150% increase in fatigue life for original specimens while the increase of fatigue life for shot-peened and repaired specimens is around 105%. The in depth residual stresses are measured on the repaired joints before and after fatigue loading. It can be stated that repair made a remarkable improvement into fatigue behaviour of tubular joints examined in this investigation. However, if repair is not possible, shot peening can be a good alternative to improve the fatigue life of welded joint but if repair is planned, shot peening may not be financially or technically justifiable.