Plastic limit loads for slanted circumferential through-wall cracked pipes based on finite element limit analysis

Based on detailed three-dimensional (3-D) finite element (FE) limit analyses, the plastic limit load solutions for pipes with slanted circumferential through-wall cracks (TWCs) subjected to axial tension, global bending and internal pressure are reported. The FE model and analysis procedure employed in the present numerical study were validated by comparing the present FE results with existing solutions for plastic limit loads of pipes with idealized TWCs. To quantify the effect of slanted crack on plastic limit load, the slant correction factors for calculating plastic limit loads of pipes with slanted TWCs from pipes with idealized TWCs were newly proposed via extensive 3-D FE calculations. These slant correction factors are presented in a tabulated form for practical ranges of geometry and each loading conditions. Moreover, the present FE plastic limit loads were also compared with the existing solutions of pipes with slanted TWCs. These FE plastic limit load solutions can be applied to estimate elastic-plastic fracture mechanics parameters and creep fracture mechanics parameters, such as elastic-plastic J-integral and crack opening displacement, creep C*-integral and creep crack opening displacement, based on the reference stress concept considering more realistic crack shape.