For the application of this study, an aircraft jet engine rotor disk under constant temperature (room temperature) is selected. Assuming crack initiation to occur at the rim slot of an aircraft jet engine rotor disk under constant temperature (room temperature) for the application of this study, and converting the three-dimensional stress into a two-dimensional one, their life prediction is analyzed. The life prediction system was predicated on stress analysis, nondestructive testing, and material properties. The stress at the cracked part of the rim slot is calculated by the finite-element method, and the crack propagation is calculated by Paris's rule. Assuming KIc and the difference between KIc and calculated K—that is, (KIc − K)—to be a Gaussian distribution, safety is estimated by the relationship between fracture probability, Pf, and standard deviation.
In the numerical examples, assuming an elliptic surface crack at four different parts of the rim slot, the crack propagation after 2000 cycles is calculated. The safety factor of rotor disks is judged by the value of (KIc – K).