Application of a laser-based time reversal algorithm for impact localization in a stiffened aluminum plate

Non-destructive testing and structural health monitoring (SHM) techniques using elastic guided waves are often limited by material inhomogeneity or geometrical irregularities of the tested parts. This is a severe restriction in many field s of engineering such as aerospace or aeronautics, where typically one needs to moni tor composite structures with varying mechanical properties and complex geometries . This is particularly true in the case of multiscale composite materials, where anisotro py and material gradients may be present. Here, we provide an impact localization algorit hm based on time reversal and laser vibrometry to cope with this type of complexity. Th e proposed approach is shown to be insensitive to local elastic wave velocity or g eometrical features. The technique is based on the correlation of the measured impact response and a set of measured test data acquired at various grid points along the specimen surface, allowing high resolution in the determination of the impact point. We present both numerical finite element simulations and experimental measurements t o support the proposed procedure, showing successful implementation on an eccent rically stiffened aluminum plate. The technique holds promise for advanced SHM, potent ially in real time, of geometrically complex composite structures.