Identification of Delamination Defects in Metal-Composite Shells Using Pulse Thermography

Thermal image analysis can be used to identify and detect patch defects in the interface between multilayer sheets. Specimens made for testing were carbon fiber and glass fiber patches on aluminum sheets that were embedded in composite patch layers, for interlayer separation, in different metal-patch joints. The defect pattern was designed so that the bugs at the edge and center of the patch were tested simultaneously. In this study, the effects of depth and dimension of separation faults with pulsed heat treatment were identified and investigated. Then, the factors affecting the accuracy of the identified defect size were investigated. In the thermal images obtained, almost all the defects can be identified by pulsed thermography and with increasing the size of the defect the thermal difference with the sound areas increases. It was found that the defects in the carbon fiber field were up to an average of 1°C, there was a greater thermal difference than that of glass fiber field. However, the results showed that the accuracy of the measurement of defects in glass fiber was 2 times higher than that of carbon fiber.