Influence of Delamination Characteristics in Carbon Fibre/Epoxy Laminates on Signal Features of Pulse Thermography

Carbon fibre reinforced polymer specimens were used in double cantilever beam tests in order to investigate the influence of delamination characteristics on multiple signal features extracted from active thermography data. During mechanical loading, delamination opening and growth were induced, allowing controlled setting of different configurations. In addition to the standardised specimens, specimen geometries were altered to investigate delamination depth and influences from two overlapping delaminations in different depths. The thermography data was obtained from a measurement where the specimens were subjected to a rectangular long pulse emitted from a halogen light. From the data various signal features were extracted. Correlations between signal features such as phase angle difference and delamination opening were investigated. Furthermore, a comparison of the relation between extracted features allowed identifying different sections of the delamination, proving the methods applicability as a detailed classification tool. Due to the high number of features extracted robustness is increased.