Axially-cracked pipes under pulsating internal pressure

Approximate values of stress-intensity factor along the front of an external axial (longitudinal) surface flaw in a round pipe subjected to an internal pressure are computed by employing both the superposition principle and the power series expansion of the actual hoop stress distribution. Then the propagation of such a defect under pulsating internal pressure is numerically predicted by assuming that the crack front presents a semi-elliptical shape during the whole growth of the flaw, and fatigue life of the cracked structural component is evaluated. Thick- and thin-walled pipes are examined, and some results are compared with those of other authors.