Wide-area impact damage evaluation with sonic infrared imaging NDE in advanced composite structures

Abstract

Sonic Infrared (IR) imaging is a relatively new member in the NDE technology family. This method combines a short pulse of ultrasound excitation, typically a fraction of a second, and infrared imaging. It has been shown its great advantage as a NDE technology to detect defects such as cracks in metal/metal alloy structures. As an imaging technology, Sonic IR is capable of wide area evaluation. Composite materials have been used in broader applications due to its light weight and stiffness. However, composites suffer more to impact than metal structures. Such damage in composites may not present at the surface but severe damage could have occurred in deeper layers. In such case, the structure strength is greatly weakened. We have been studying impact damages in composite structures with Sonic Infrared Imaging, and evaluating how structures affect thermal signatures in defect characterization. In this paper, we will present our study on composite panels containing structures such as doublers and beams or stiffeners, which were subjected to impacts from varying energy projectiles.