State-of-the art non-destructive techniques for defects detection in nanocomposites foam-core sandwich panels containing carbon nanotubes: IR thermography and microwave imaging

In this article, the state-of-the art of infrared (IR) thermography and microwave non-destructive (NDT) testing for inspection of defects in carbon nanotubes-based nanocomposite sandwich panels has been presented. Different types of defects such as holes, notches and inclusion (Teflon) have been simulated in the polymeric foam-core of sandwich panels. The infrared (IR) thermography and microwave methods have been conducted to assess the simulated defects in the sandwich panel. The thermography results revealed that the thermal energy absorbance was higher in sandwich panel containing multi-walled carbon nanotubes (MWCNTs), however, various types of defects were well detected in both specimens with and without MWCNTs. From the result of microwave imaging, the same probability of NDT inspection was observed for detecting subsurface defects in sandwich panel and its nanocomposites. The use of low content of MWCNT (0.5 wt%) did not significantly affect on the microwave absorption properties of sandwich panel among NDT procedure, however some changes of reflection coefficient amplitude in selected frequency bands were observable.