Pulsed and Vibro Thermographic results

The CFRP specimens were manufactured and purposely damaged via impact, in the Cranfield composite centre. Sample A4 was manufactured via manual woven, and the other twosamples were unidirectional. The composites consist of laying up pre-pregpiles to form a laminate stack, the material is then autoclave processed at 180oCand 7 bars for a few hours suitable for the thermoset resin cure, this isaccording to the supplier’s specification (Hexcel). There were three specimens,one that was undamaged, and two that had been impacted with a force of 15 and20 J of energy. The infrared camera used in this experiment was a FLIR Phoenix,with inSb sensor material, 3-5 mm, 640x512 pixels and allows data acquisitionat 50Hz. Thesurface of the specimens were positioned parallel to the camera lens. The data was acquired for 40 seconds with a 1.5millisecond integration time, that includes 10 frames before the flashes, plus1990 frames during cooling a total of 2000 frames where recorded. The softwareused to acquire the data was RDac from FLIR. For signal processing MATLAB andIr_view from Visiooimage inc were employed. Two advanced processing techniqueswere used; PCT (principal component thermography) and PPT (pulsed phasethermography).