Numerical analysis of crack initiation and growth in cylindrical geometries with an axial flaw

In this work we study the initiation and growth of a semi-elliptical internal axial crack in the wall of an internally pressurised cylinder. We show that small diameter structures, which we may call ‘tubes’, are more likely to undergo noticable yield before a small internal flaw starts to grow. However, when growth starts, it is likely to be catastrophic. On the other hand, large diameter structures, called ‘pipes’, can fail by cracking at reasonable design pressures. We have also shown that a small semi-elliptical crack attains a particular (almost circular) shape during growth irrespective of its initial aspect ratio.