Artificial Specimens Manufacturing of Glass Fibre Reinforced Composite for Sub-surface Defects Inspection By Active Long-pulse Thermography

The detection and analysis of sub-surface defects in composite materials specimens have been problems of interest in recent years in different industries. For instance, in the wind industry, such materials are used for manufacturing wind turbine blades. A variety of defects can occur inside composite materials, e.g., porosities, fibre rupture, and inclusions. This work presents the design and manufacturing of artificial test specimens of composite material, to which specific defects were induced in a non-destructive way. The used manufacturing process was VARTM. In addition, a method to localise and characterise induced defects is proposed. Such method works by applying active long-pulse thermography to the test specimens. Further, we show that both the proposed low-cost optical system and the long-pulse active thermography technique allow the non-destructive thermal analysis of parts to detect sub-surface defects in composite materials based on fiberglass reinforced epoxy resin