Flaw Detection Reliability Criteria. Volume 1. Methods and Results.

Abstract : Air Force inspection limits for damage tolerance analyses have been defined as those crack lengths for which there is 95 percent confidence that at least 90 percent of all cracks will be detected. This definition of inspection limit cannot be used in structural risk assessments as it is not linked to the probability of missing the flaws that may be present in a structure. This program investigated alternate methods of defining flaw detection reliability criteria and, in particular, focuses on a characterization based on a fixed probability of having cracks greater than the inspection limit after the inspection. A major part of the program was devoted to methods of estimating the POD (Probability of Crack Detection) function from inspection reliability demonstration experiments. These methods are extensively discussed. (Author)