Quantitative inspection of non-planar composite specimens by pulsed phase thermography

In pulsed phase thermography (PPT), amplitude and phase delay signatures are available following data acquisition; carried out in a similar way as in classical pulsed thermography, by applying a transformation algorithm such as the Fourier transform (FT) on thermal profiles. An extended review on PPT theory, including a new inversion technique for depth retrieval by correlating the depth with the blind frequency fb (frequency at which a defect produces enough phase contrast to be detected), has already been proposed confirming PPT's capabilities as a practical inversion technique. In this work, planar and non-planar CFRP composites were evaluated by quantitative PPT. Experimental results showed that, for the geometries studied here, surface shape has little impact on depth inversion results.