Defect Classifications in Composites Using Ultrasonic Nondestructive Evaluation Techniques

Abstract

The growing use of advanced composites in structural applications has intensified the need for nondestructive technologies to locate, identify, and classify defects and flaws in composite structures with increasingly complex geometries. Ultrasonic nondestructive testing methods have proven to be successful and reliable in the inspection and certification of composite structures that are scanned by sophisticated, automated, multiaxis robotic systems. Digitizing of the ultrasonic information has introduced powerful computer graphics image enhancement techniques to aid in the interpretation of the results. Research results of comparative studies are presented that take advantage of advanced robotic scanning and subsequent image enhancement technologies. A variety of ultrasonically detectable defects such as porosity, contaminations, delaminations, fiberor matrix-rich areas, fiber orientation, and impact damage are interrogated. Flaw growth models for fatigue samples are discussed, addressing the flaw criticality issue, a growing area of interest in the characterization of composite structures.