Bursting pressure of autofrettaged cylinders with inclined external cracks

Autofrettaging a pressure vessel improves its pressure capacity. This is reliable if there isn’t any crack or other type of flaws. In this paper, the effects of external surface cracks on bursting pressure of autofrettaged cylinders are studied. It is observed that bursting pressure decreases considerably (up to 30%) due to external cracks in the cylinders without autofrettage. This reduction increases for high levels of the applied autofrettage. External axial cracks have more effects than inclined cracks. Comparing experimental and numerical results show that the numerical methods can acceptably predict the bursting pressure of the autofrettaged cracked cylinders. These predictions are valid when the fracture parameter (J-Integral) is calculated from the modified equation that takes into account the effects of residual stresses.

► Modified J-Integral can be used for study of autofrettaged cracked cylinders.
► External axial cracks reduce considerably the pressure capacity of cylinders.
► External circumferential cracks have not considerable effects on bursting pressure.
► Autofrettage has contrary effects on external crack in compared with internal crack.