On a plastic limit loads of complex-cracked pipes with weld overlay using finite element limit analyses

In the present study, the plastic limit loads of the complexcracked pipes, which have 360° internal surface crack along the circumference of pipe together with partial through-wall crack, are investigated via detailed 3-dimensional (3-D) finite element (FE) limit analyses. In terms of geometry of the complexcracked pipe, the Alloys 82/182 butt weld that has welds overlay using the Alloys 52/152 for mitigating primary water stress corrosion cracking (PWSCC) in the nuclear pipe is considered. In the present FE limit analyses on complex-cracked pipes with welds overlay, the effect of strength mismatch between Alloys 82/182 and Alloys 52/152, depth of 360° internal surface crack and length of partial through-wall crack on plastic limit loads of complex-cracked pipes is systematically evaluated. As for loading conditions, axial tension, global bending and internal pressure are employed. The resulting FE plastic limit loads of complex-cracked pipes with welds overlay are also compared with the existing solutions, and finally the applicability of simple engineering estimate using the single material property based on the weighted average concept instead of using the properties of Alloys 52/152 and Alloys 82/182 to the prediction of the plastic limit loads of complex-cracked pipes with welds overlay is pursued.