Cost-based optimal history-dependent inspection strategy for random fatigue crack growth

Optimal inspection time for random fatigue crack growth is theoretically investigated based upon cost-minimization, by the use of a diffusive crack growth model. Assuming that a component is immediately replaced if a crack is detected by the inspection, we discuss a method to decide the optimal inspection schedule for a history-dependent strategy and newly propose an approximation method to derive it easily. By comparing the inspection schedule derived by the method with the optimal one through numerical calculations, we verify the appropriateness of it.