Fatigue analysis of manufacturing defects in weldments

Abstract The effects of lack of penetration and misalignment on the fatigue life of cruciform welded joints made of low alloy steel have been studied experimentally and theoretically. It was found that two locations of fatigue fracture were possible under cyclic tension loading, depending on the misalignment. In the absence of misalignment, fatigue fracture occurred as a result of fatigue growth of pre-existing non-penetrating flaws. The fatigue lives of such joints were dominated by the crack growth period, with relatively little time being spent in initiating the crack. In the presence of some misalignment the fatigue life was spent substantially on fatigue crack initiation in the weld toe. The detrimental misalignment effect was more apparent under a low stress ratio of R = −1 .