Quantifying NDI capability for damage tolerance analyses

This chapter evaluates the joint effect of nondestructive inspection (NDI) and crack sizes by calculating the failure probability for selected combinations of the probability of detection (POD) functions and crack size distributions. The effect of the NDI process is considered by calculating the percentage of cracks greater than an equivalent crack length (a /SUB NDI/ ) which are not detected and the percentage of all details which are rejected by the inspection. Topics considered include the analytical framework, a Weibull distribution of crack sizes, and the uniform distribution of crack sizes. It is suggested that in quantifying NDI capability for damage tolerance analysis, the following computations should be considered: the probability of not detecting a crack greater than a /SUB NDI/ , the percent of cracks greater than a /SUB NDI/ which are not detected, and the total percent of details which are rejected