Structural damage detection using residual forces based on wavelet transform

This study attempts to develop a wavelet-based method, which not only localizes multiple damage sites but also provides information on when damage occurs. By performing wavelet transform of free vibration responses of structures in the damaged state, a residual wavelet force (RWF) is defined. The damage locations and the moments when damage occurs are easily determined simultaneously by the ridges in the RWF. A damage location indicator, DLIRWF, is also presented. The degrees-of-freedom that have large magnitudes in DLIRWF are associated with the potential damage members within the structure. Furthermore, the natural excitation technique is introduced to generalize the proposed method to the cases of ambient vibration. The proposed method has been demonstrated by numerical simulations of a 20-story shear building and a 5-story, 1-bay×2-bay steel-frame structure.