Creep crack growth characterization of SS316LN

In creep conditions, conventionally, C* and C(t) line integrals are used for characterising the crack tip. However, the true crack driving force or its rate cannot be described by any of the conventional parameters. The theoretical validity of conventional crack tip-characterising parameters like J or Ct is also restricted, making it hard to anticipate the driving forces underlying cracks. To investigate the creep crack growth behaviour of this material an experimental analysis of SS316LN at 650 °C is performed. The crack extension is modelled through the node-release technique, and a configurational force-based rate of change of J integral is calculated by post-processing of the finite element results. The results show that the Ct and dJepc/dt calculated from FE analyses are similar and the trend is also similar to the experimentally measured C*-values.