Application of continuous wavelet transform in vibration based damage detection method for beams and plates

In this paper a method for estimating the damage location in beam and plate structures is presented. A Plexiglas cantilever beam and a steel plate with four fixed boundary conditions are tested experimentally. The estimated mode shapes of the beam are analysed by the one-dimensional continuous wavelet transform. The formulation of the two-dimensional continuous wavelet transform for plate damage detection is presented. The location of the damage is indicated by a peak in the spatial variation of the transformed response. Applications of Gaussian wavelet for one-dimensional problems and reverse biorthogonal wavelet for two-dimensional structures are presented. The proposed wavelet analysis can effectively identify the defect position without knowledge of neither the structure characteristics nor its mathematical model.