Ultrasonic and IR Thermographic Detection of a Defect in a Multilayered Composite Plate

Multi-layered composites are frequently used in many applications as constructional materials. Such materials represent a difficult inspection task for some traditional techniques of non-destructive testing (NDT). Typical defects of composite materials are delaminations, lack of adhesion and crumpling, just to name a few. IR thermography and ultrasonics are typically considered as candidate techniques to detect different types of defects. In order to assess the potential usefulness of both methods, a composite laminate with a polytetrafluoroethylene disk inserted between two layers to simulate a delamination is investigated. Experimental evidences resulting from the two technologies are discussed.