Improving NDE Through Multiple Inspections

Current nondestructive evaluation techniques generally do not produce identical indications when applied to flaws of the same length. The chance of detecting a given crack length depends on many factors, such as the location, orientation and shape of the flaw, materials, inspectors, inspection environments, etc. As a result, the probability of detection (POD) for all cracks of a given length has been used in the literature to define the capability of a particular NDE system in a given environment. Some POD curves are shown in Fig. 1 for various laboratory inspection techniques. Many other POD curves can be found, for instance, in Refs. 1–3