On the use of the polynomial annihilation edge detection for locating cracks in beam-like structures

A crack in a structure causes a discontinuity in the first derivative of the mode shapes: On this basis, a numerical method for detecting discontinuities in smooth piecewise functions and their derivatives, based on a polynomial annihilation technique, has been applied to the problem of crack detection and localisation in beam-like structures for which only post-damage mode shapes are available. Using a finite-element model of a cracked beam, the performance of this methodology has been analysed for different crack depths and increasing amounts of noise. Given the crack position, a procedure to estimate its depth is also proposed and corresponding results shown.

► Cracks in beams can be detected and located using the numerical method presented. ► At the crack position, the first derivative of mode shapes exhibits discontinuity. ► Only details of the post-damage mode shapes are required by this method. ► Knowing the position of the crack, its depth is estimated with a new procedure. ► Simulated data are used to analyse the method performance for various crack depths.