Hybrid procedure to characterize hidden defects in composite materials

Among the non destructive methods used for the control of composite material, the infrared thermography is being given more and more attention since it enables to analyse the effects induced by the anomalies on the thermal behaviour of the material. In particular the Lock-in and the Pulse techniques can provide information about the dimension and the depth of the defects. The present work aims at exploit the results given by the thermographic analysis, after a continuous heating by means of a microbolometric thermocamera, by defining a hybrid procedure, numerical and experimental. The main purposes of the hybrid procedure are: determining the characteristics (in terms of dimensions and depth) necessary in order to make a certain type of defect detectable inside a laminate of composite material; discovering the minimum prerequisites which a thermographic detection system should have.