Three-dimensional flaw shape reconstruction by linearized inverse scattering method

The linearized inverse scattering method reconstructs the shape of flaw by low frequency wave data obtained by ultrasonic measurement. It is possible for this method to be a practical NDE method for concrete structures. Performances of the two-dimensional inversion formulae have been studied by both numerical simulation and experimental measurement. In contrast, no experimental shape reconstruction by three-dimensional inversion formulae has been studied. In this study, numerical simulation is used to discuss the effects of scattering the amplitude's wavenumber on reconstructed shapes of flaw models. Cement paste specimens are prepared based on the numerical simulations, and backscattered waveforms from all directions surrounding a flaw model are obtained. The wave data are fed into inversion formulae, and performances of the method are verified by comparison with X-ray CT scan images.