Effect of L/Tp ratio on fatigue life prediction of SMAW cruciform joints of ASTM 517 ‘F’ Grade steels

Abstract New fracture mechanics equations have been developed to predict the fatigue life of shielded metal arc welded (SMAW) cruciform joints of ASTM 517 ‘F’ Grade steels, containing lack of penetration (LOP) defects. These equations have been developed by combining the Paris law with the Δ K i -endurance equation The initiation life ( N i ) and the propagation life ( N p ) of the joints were accounted for, to obtain the total fatigue life ( N f ). The initiation life was obtained experimentally using crack initiation criteria. The propagation life was evaluated using the numerically developed equations. The accuracy of the developed equations were tested by comparing the predicted data with the experimental data and it was found that the correlation is quite good. Further, the effect of L / T p ratio (weld size) on fatigue life prediction was analysed in detail.