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Figure 1. Instrument Signal Characteristics by Technique, with working frequencies. Sources as listed on the figure and in the article. Scope This article addresses the capabilities of the different Bond Testing techniques and the instrument signal characteristics that are used in each of the techniques, as well as the frequency and probe variables that are…

Similar looking ultrasonic responses can come from very different changes in a composite structure. A 12 dB amplitude reduction in a composite does not identify the damage mechanism. It identifies a change in the acoustic response. That change may be associated with an interply delamination, a bonded-interface separation, distributed porosity, a thickness transition, local laminate…

The hidden cost of an indeterminate NDT result The scaffolding is down. The insulation is back on. The NDT crew has demobilized. Engineering opens the report and finds a response that could not be adequately characterized. Now everyone has the same question: What exactly did we find? At that point, the cost of the original…

An AUT corrosion map should do more than identify the lowest thickness on a component. The useful question is not simply, “What is the minimum wall?” The useful questions are where that minimum is located, how the wall changes around it, what process or geometric features are nearby, whether the damage pattern is consistent with…

Photo: National Transportation Safety Board (NTSB), public domain What if someone in an NDT, inspection, quality control, quality assurance, asset integrity, or engineering setting says, “Level IIIs aren’t that important,” or “I’m not worried about what the Level III thinks”? That should raise a question. The issue is not whether a Level III should win…

A weld can be fully exposed and still be difficult to examine. That usually becomes obvious when the probe is coupled to the component. And now, well, a technique revision may be needed. A drawing may show enough room on both sides of the weld. In the field, weld reinforcement, curvature, a nearby fitting, support,…

Why effective NDT technique selection begins with the condition being evaluated In nondestructive examination, it is easy to begin with the equipment. What instrument is available? Which probe should be used? Should the examination use ultrasonic testing, eddy current testing, phased array ultrasonic testing, full matrix capture & total focusing method, or another method? Those…

Let’s bring some clarity to WHY detection, sizing, characterization, and interpretation are different examination objectives In nondestructive testing, finding an indication may be only the beginning of the examination process. An examination technique may produce a repeatable response from an area of interest, but the presence of that response does not necessarily answer the questions…