| Abstract: | Thermographic nondestructive testing (NDT) based on the thermal resistance effect of defects is developed for the inspection of delaminated and sandwiched defects embedded in composite structures. The resolution is examined for artificial delaminated defects in carbon-fiber honeycomb structures using conventional infrared radiation heating. The experimental results have demonstrated that radiation heating is effective for revealing defects in the composite structures.An experimental and computational hybrid system is developed for detecting defects in various composite structures. The system consists of an infrared thermal video system which measures the surface temperature distribution of the structure, a computer with a PIP-1024B image board which performs image processing of thermograms, and a HP ink jet XL printer. It is found that this system is readily applicable to the detection of defects located at the interface of the core and skin in honeycomb structures and delaminations in composite materials. |
