A procedure for estimating the probability of flaw nondetection

A mathematical expression has been obtained for the probability of flaw nondetection in pressure vessels. The authors have also derived the distribution function of the largest undetected flaw. Specifically, the probability that at least one flaw of a size a or more is left undetected after a sequence of flaw inspection procedures is carried out can be estimated. This solution takes into account (i) the number of flaws initially present in the vessel, (ii) the sizes of these flaws, and (iii) the detection capability of the inspection procedures. The result given here can be used in assessing the effectiveness of various inspection sequences and in obtaining an estimate of the unconditional probability of brittle fracture. (Auth.)