Thermosonics: array-based, air-coupled ultrasonics and thermography for NDE of carbon fibre reinforced polymer materials

A commercially-available air coupled piezoelectric array was used to induce thermosonic heating in damaged CFRP. Themosonic heating of the damage has been observed with an IR camera. The intensity of the thermosonic heating decreased with the increased distance of the ultrasonic excitation from the damage, as would be expected with energy dissipation into the CFRP. The use of an array allowed scanning of the focal point across a sample to locate and image areas of damage, without moving either the array or the camera. This scanning capability could increase the speed at which composites can be inspected, reducing the current laborious contact transducer methods.