Prediction of creep crack growth for modified 9CR-1MO at 600°C

This paper introduce theoretical creep crack growth prediction model and provides experimental validation of the approach for simulating creep crack growth using finite element analysis method, recently proposed by the authors. The FE creep damage model is based on the creep ductility exhaustion concept, and incremental damage is defined by the ratio of incremental creep strain and multi-axial creep ductility. A simple linear damage summation rule is applied. When accumulated damage becomes unity, element stresses are reduced to zero to simulate progressive crack growth. For validation, simulated results are compared with experimental data for a compact tension specimen of modified 9Cr-1Mo at 600°C under various loading levels. The simulated results agree well with experimental C*-da/dt data. The test data are also compared with theoretical CCG prediction model.