Understanding Infrared Thermography Reading 7 Part 2 of 2.pdf

This approach requires the generation of a controlled flow of thermal energy
across the laminar structure of the sample material under test, thermography
monitoring of one of the surfaces (or sometimes both) of the sample, and a
search for anomalies in the thermal patterns that will indicate a defect in
accordance with established accept-reject criteria. This approach has been
used extensively and successfully by the aerospace community in the
evaluation of composite structures for impurities, flaws, voids, disbonds,
delaminations, and variations in structural integrity. Most recently, time-based
heat injection methods have been applied successfully to measure the depth
of voids, as well as their location. This is effective because thinner sections of
a given material will heat more rapidly than thicker sections.
Charlie Chong/ Fion Zhang