Limit load analysis of pressure pipes with partial-through circumferential cracks

Abstract Limit load predicted by Net Section Collapse Criteria (NSC) is usually used to evaluate the residue strength of structures with defects. In this work, the critical bending moment for pressure pipes with circumferential cracks is obtained based on NSC with two different assumptions of neutral axes on cross-sections for both thin-walled and thick-walled pipes. For thin-walled cases, it is proved that a simplified model provides critical bending moment expressions the same as the classic solutions that has long been adopted in widely accepted regulations such as ASME and JSME. It also provides results the same as a more rigorous model as long as the relative wall thickness remains small enough. However, the use of the simplified model may lead to an underestimation of the critical bending moment up to 17% compared to the rigorous model for pressurized thick-walled pipes with long and deep circumferential cracks.