Thermographic inspection of composite structures

Although the potential of thermographic nondestructive evaluation for composite materials has been widely recognized, until recently implementation has been limited to qualitative applications, where thermography served as an adjunct to ultrasonic or x-ray inspection. However, recent advances in the field have allowed thermography to perform as a stand-alone inspection technology for manufacturing or maintenance applications, offering fast, wide area, single-side performance that is comparable to conventional inspection methods. These advances, which include. improvements in signal processing, acquisition strategies and a better understanding of fundamental interactions, are described. Characteristic defect conditions in composites, and quantitative measurement of physical properties, including thickness, defect depth and thermal diffusivity are also discussed.