A DUCTILE FRACTURE MODEL FOR A PIPE WITH AN AXIAL SURFACE CRACK

The ductile limit state of a thin-walled cylinder with an axial extern al crack has been studied. The limit state occurs when the applied mom ent reaches the limit value for a given section. It is pointed out tha t the main computational difficulties are concerned with quantifying t he ability of the crack containing section to resist the simultaneous action of a bending moment and other loadings. A number of variants of the limit pressure evaluation have been proposed. All the variants ar e in good accordance with experimental data and give similar results a t considerable positive axial force (more than 0.2-0.3 of the limit). An empirical layout taking into account the wall thickness of comparat ively thick-walled pipes has been proposed.