Studies of the Depressurization of Gas-Pressurized Pipes during Rupture

Measurements are presented of the initial rates of depressurization generated within ductile steel pipes in pneumatic rupture tests. The breach was initiated by failure of an axial, part-through, flat-bottomed defect machined in the outer surface of the pipe.

The measured depressurization rates for supercritical defects are shown to be in agreement with values predicted by a theoretical model which assumes that the pipe hinges open. Where the initial defects are longer than two pipe diameters, the extent of the hinging section is defined by the initial defect length. For short initial defects, a significant breach does not develop until the defect has propagated axially to a length of the order of two pipe diameters, and hence the effective hinging length is two pipe diameters Initial depressurization rates for subcritical defects correlate with the Folias bulging parameters.