INVESTIGATION ON THE STRUCTURAL DAMAGE ALARMING METHOD BASED ON WAVELET PACKET ENERGY SPECTRUM

The state and observation equations of structural dynamic systems in various analysis scales are derived based on wavelet packet analysis.The time-frequency properties of structural dynamic responses in various scales are then investigated together with the transfer properties of system matrix and observation noise.The theoretical analysis results reveal that structural damage alarming using wavelet packet energy spectrum of the structural dynamic responses has preferable damage sensitivity and noise robusticity.According to the characteristics of instantaneous stimulations,the wavelet packet energy spectrum is obtained using the wavelet packet decomposition of the cross-correlation of stimulation and response signals in time domain,based on which the structural damage alarming index is obtained.Through a vibration testing analysis of a reinforced concrete slab subjected to static loading series,the damage status of the slab during different loading phases are determined and compared with the actual deterioration states.