Update and Default Probability of Detection Curves for the Ultrasonic Detection of Hard Alpha Inclusions in Titanium Alloy Billets

摘要

This report describes efforts to update the default probability of detection (PoD) curves for the ultrasonic detection of hard alpha inclusions in titanium alloy billets, with the results intended to replace the curves currently found in Advisory Circular 33.14-1, Damage Tolerance for High Energy Turbine Engine Rotors. This report describes the data on which the update is based, the statistical approaches used to analyze those data, the results of the PoD analysis, technical issues encountered during the analysis, and conclusions. The original Default PoD curves were based on what is known as the Default PoD-3Dimensional database, which documents the results of inspections conducted before 1995 using conventional inspection techniques. Two additional sets of data that became available after 1995 are described in this report and greatly extend the information available. The updated PoD curves are found to be considerably different from the previous curves, obtained in 1995, with the PoD of the Multizone technique shown to be clearly superior to that of the conventional inspection technique.