In structures having stress concentration under cyclic loading, a small crack initiates and it grows and propagates. Evaluating crack growth is important to estimate the remaining life of cracked components.
The present paper shows the estimation of crack growth rate under creep-fatigue loading with some patterns of strain holding times.
Creep-fatigue tests of the perforated plate having initial crack were conducted with the different strain holding time under strain-controlled loading at 550°C. The crack growth was observed from the photographs taken at each cycle. The crack growth per one cycle of creep-fatigue loading was evaluated by the creep-fatigue crack propagation law which used increment J-integral range. Comparing the crack growth rates of experimental with those of predicted, the crack growth rates were predicted by using increment J-integral range with the accuracy was factor of 2.