Fourier analysis applied to Infrared Thermography of Fiber Composites used for the Strengthening of Structural Elements

Fiber reinforced polymers (FRP) composites are an efficient method in the strengthening of civil structures. FRP systems are usually applied by means of a wet lay-up method. National guidelines recognize that Infrared Thermography (IRT) is a possible non-destructive evaluation (NDE) technique for the detection of bonding defects, voids and damages and the characterization of the surface layers without a direct contact between the device and the observed area. Conversely, in the guidelines no clear indications are given about the inspection procedure.