ROLE OF QUANTITATIVE NDE TECHNIQUES IN PROBABILISTIC DESIGN AND LIFE MANAGEMENT OF GAS TURBINE COMPONENTS - PART II

摘要

A number of earlier publications discussed the benefits of probabilistic lifing in application to critical rotating engine components. One of the key random variables in both probabilistic and deterministic damage tolerant analysis is a probability of detection (POD) that represents a quantified Non-Destructive Evaluation (NDE) capability. The importance of having accurate POD information and its use in the probabilistic design and life management process is further promoted by the changing customer and regulatory requirements. New and existing FAA / EASA regulations and Air Force standards require damage tolerance analysis to be performed on critical engine components. POD for an NDE inspection is recognized as an important input for damage tolerance analysis. This information is needed for establishing and optimizing inspection schedules, calibrating life predictions, calculating fleet risk etc. Sensitivity of the above results to the accuracy of the POD curve, and to its approximation with a single point value (e.g. 90/50 POD = value of 90% probability with 50% confidence) will be discussed and illustrated with numerical examples. A brief overview of the methods for generating POD curves, and recent advancements in this area will be presented as well.