Creep crack growth simulation under transient stress fields

The validity of the C -integral for correlation of creep crack growth under transient and steady-state stress fields has been investigated, using FEM analysis. In the steady-state regime, crack growth rates can be correlated withC*, however only for limited amounts of crack extension. When a crack grows in a transient regime no correlation of crack growth is found with any of the conventional crack tip parameters. For both regimes the most relevant parameter is theC-integral values obtained from the near-field region ahead of the crack tip.