Photothermal imaging of foreign object defects in curved orthotropic composite samples

In this research work, photothermal reconstruction for imaging foreign object defects in curved orthotropic composite samples is demonstrated using the virtual wave concept. For this purpose, the virtual wave concept is extended for defect reconstruction in orthotropic samples with a surface curvature in one direction. Furthermore, it is discussed how the multidirectional heat flows due to the complex-shaped geometry influences the propagation of the virtual wave. For verification, photothermal experiments with single-pulse flash lamp excitation in the pulse-echo configuration are performed. In summary, this study underlines the capability of the reconstruction scheme for imaging defects in strongly curved composite components.