Pulsed Thermography for the NDT of Honeycomb Composite Structure

Honeycomb sandwich Composite has wide applications in manufacture, such as aircraft, automobile, rail transit, and so on, due to its special advantages. However, defects always exist in the honeycomb composite during manufacturing and in-service period, liquid ingress and debondings are the most typical defects. In this paper, according to the NDT problem for this kind of material, Pulsed thermography is applied, theoretical model of heat conduction for the defect detection under an instantaneous heat source is analyzed; Several kinds of honeycomb composite specimen is designed for the two typical defects detection; Pulsed thermography is applied on the specimens and the defects are revealed by the thermal images sequence processing. Furthermore, by analyzing the logarithmic temperature decreasing curves can distinguish different types of liquids under the skin. Results show that Pulsed thermography has advantages for the NDT of honeycomb composite.