Experimental investigation of a combined method of damage location in composite beams and plates

A combined method of damage detection for composite structures is proposed. In this method, only the vibration responses of the damaged structure are measured under a steady random excitation in order to calculate the cross correlation function amplitude vector (CorV). A reference CorV is obtained by smoothing curve fitting of the measured CorV of the damaged structure in a least-squares sense. Then, the continuous wavelet transform is applied to the measured CorVs and the reference CorVs respectively. The modul of difference between the wavelet coefficients of measured CorVs and reference CorVs are calculated as the index of damage localization. The validity of the proposed method is verified by experiments on a composite honeycomb beam with prefab debonding damage and a composite laminate plate with prefab de-lamination damage.