Three-dimensional defect reconstruction in carbon fiber-reinforced composites with temporally non-uniform pulsed thermography data

This research study presents an efficient and comprehensive three-dimensional photothermal reconstruction scheme for non-uniform pulsed thermography data utilizing the virtual wave concept. For the transformation of temperature signals into virtual wave signals, different physical-based temporally non-uniform sampling techniques for the temperature and the virtual wave signal are used. Furthermore, time reversal is implemented for three-dimensional defect reconstruction in the context of temporally non-uniform sampling. The proposed reconstruction scheme is experimentally demonstrated using carbon fiber-reinforced composite samples with foreign object defects as well as flat bottom holes. To sum up, a reconstruction technique is demonstrated that allows increasing the computational efficiency, while retaining the quality of the reconstruction results and simultaneously reducing data storage requirements compared to conventional temporally uniform sampling.