Detection and localisation of structural damage based on the Polynomial Annihilation Edge Detection: an experimental verification

This paper describes an experimental validation of a new structural damage detection method based on the Polynomial Annihilation Edge Detection (PAED) technique, a numerical method for detecting discontinuities in smooth piecewise functions and their derivatives. Since it is well known that concentrated damage such as a crack, causes a discontinuity in the rotations and consequently in the first derivatives of the mode shapes and in general of the deflection shapes of beam-like structures, the PAED can be applied to the problem of damage detection and localisation in these kind of structures for which only post-damage vibration measurements are available. As described in this paper, in order to verify this approach experimentally, vibration tests on a cantilever steel beam with a saw-cut have been performed and Operational Deflection Shapes (ODSs) determined. Since the approach requires a reasonably high spatial resolution of the ODSs, a scanning laser vibrometer, capable of acquiring data rapidly at a very large number of observation points, was used.