Frequency analysis of ultrasonic signals for non-destructive diagnosis of masonry structures

The target of this work is to define a new procedure for the non-destructive diagnosis of masonry structures in order to highlight and analyze the presence of material defects, such as fractures, cavities or inhomogeneities which might reduce the structural stability. Among the various non-destructive techniques an ultrasonic method has been chosen. In order to determine the signal characteristics most closely correlated with the presence of defects inside the masonry, a finite element analysis (FEM)was carried out on a 2Dstone masonry model, followed by a frequency analysis of the acquired signals. For each frequency component, the level of correlation with the average density of the medium has been then evaluated, extracting the most interesting features. Finally, in order to verify the feasibility of the proposed approach, the same procedure has been applied to a real stone masonry with a known internal cavity