Strain-controlled creep rupture in an internally-notched pressurized tube by the finite element technique

Abstract

A creep rupture analysis of an internally notched thick-walled tube, subjected to a constant internal pressure, is carried out in detail based on the local continuum damage mechanics approach using the finite element technique. A strain-controlled creep damage law, which is derived from a more complex strain-dependent creep damage law, is employed to evaluate the damage due to creep. Because of the presence of the notch and hence the associated extremely non-uniform damage field, a localized “crack”, which is defined as the region of ruptured zones, initiates at the notch tip and then propagates through the notched section. While the crack advances with a monotonically but slowly increasing rate during most of the rupture life, it propagates through more than half of the notched section in essentially zero time. This behavior of the crack propagation is a consequence of the creep ductility as well as the loss of load-carrying material at the notched section.