Engine Component Retirement-for-Cause: A Nondestructive Evaluation (NDE) and Fracture Mechanics-based Maintenance Concept

A Reliability-Confidence Methodology for Complex Systems

“…To avoid confusion it is convenient to subtract from (1) the expected values of the probabilities, (PF> and (P n > and write in the form x (2) X can be regarded as a sum of steps xn with random lengths, and one can study the statistics for an R-C interval for X (i.e., system p,robability of failure, in terms of the statistics for R-C intervals of the x n ' i.e., flaw state probabilities).…”

Synthetic aperture focusing of ultrasonic inspection data to enhance the probability of detection of defects in strongly attenuating materials

“…the smallest tolerable defect sizes can inferred from hydrodynamic load calculations and fracture mechanical considerations [5]. In this respect, the POD-concept originally developed for the US Air Force focusing on turbine engine inspection [6,7] is particularly interesting for such maritime applications as well.…”

“…In the case of ship propulsion components, which is of particular interest to the authors, this integrity is evaluated from hydrodynamic calculations for the propeller load states and the critical flaw sizes, which are determined from the fracture mechanical material characteristics [5]. The POD-concept has originally been developed for the US Air Force focusing on turbine engine inspection [6,7], but is applicable to other areas of NDE as well. The principal shape of a POD-curve shows that with increasing flaw size the probability of detection increases accordingly.…”