The resulting shadowgraph shows the dimensional an features of the part. Possible imperfections are indicated as density changes on the film in the same manner as a medical X-ray shows broken bones. As in ultrasonic testing, acoustic emissions can be detected by special receivers. Emission sources can be evaluated through the study of their intensity, rate and location. Several techniques are used to detect and locate leaks in pressure containment parts, pressure vessels, and structures.
Visual inspection involves using an inspector's eyes to look for defects.
The inspector may also use special tools such as magnifying glasses, mirrors or borescopes to gain access and more closely inspect the subject area. Visual examiners follow procedures that range from simple to very complex. Contact Sam Wormley . Opinions expressed are those of the authors and not necessarily those of the National Science Foundation.