Discussion on structural damage identification based on wavelet packet total energy of structural responses under random excitations

Structural damage identification based on wavelet packet energy has been applied due to its powerful timefrequency analysis capability. Current methods are mainly based on the wavelet packet total energy of structural acceleration or displacement responses, and these responses primarily reflect structural overall characteristics. Moreover, it is essential to investigate the influence of different excitations on identifying structural damage under random excitations. Therefore, three studies on structural damage identification based on wavelet packet total energy of structural responses under random excitations are discussed in this paper. First, structural damage identifications based on wavelet packet total energy of structural acceleration, displacement, and macro-strain/strain responses are discussed, respectively. Second, the effects of different excitations to intact and damaged structures on structural damage identification based on wavelet packet total energy of structural macro-strain/strain responses are also discussed. Finally, to eliminate the influence of random excitations, structural damage identifications based on transmissibility functions of wavelet packet total energy of structural macro-strain/strain responses are proposed. Through numerical studies of structural damage identification of both beam-type and truss structures, it is illustrated that the wavelet packet total energy change rate based on macro-strain/strain responses is more sensitive to local damage, different excitations significantly affect structural damage identification, and the influence of random excitations can be eliminated by the transmissibility functions of wavelet packet total energy of structural macro-strain/strain responses.