Investigation On Structural Damage Diagnosis Method Based On Wavelet Packet Energy Spectrum

As society progresses, blasting technology is used in many areas, such as large building demolition, foundation excavation, urban transportation, subway, road construction and so on. However, the impact of blasting on the surrounding environment and buildings can not be ignored. Damage may be caused to surrounding buildings by blasting seismic waves. Therefore, it's very necessary to study the damage diagnosis of buildings under blasting seismic waves. Today, building structural damage diagnosis has become the forefront of civil engineering problems in the worldwide, and it's also a challenging task in the field of structural health monitoring. The core of structural health monitoring is to design a health monitoring system, and to judge the health status of the structure with the data and signals collected, finally to assess the location and extent that damage may occur.In this paper, multi-scale damage analysis theory based on wavelet packet energy spectrum is used for building structural damage diagnosis under blasting seismic wave. According to the characteristics of blasting seismic waves, the non-stationary random process theory is used to simulate a set of explosion seismic wave data. And the wavelet packet method is used to analyze the frequency spectrum characteristics and energy distribution of the simulated blasting seismic waves. The simulated blasting seismic wave is used as the initial excitation on a steel braced frame structure, by removing the braces of the structure to simulate the structural damage. And the dynamic response of the intact structure and damaged structure is calculated under the action of the blasting seismic wave by numerical analysis method. According to wavelet transform and wavelet packet transform theory, structural damage diagnosis method based on wavelet packet energy spectrum is established. Then according to structural dynamic response, the damage warning parameters and damage warning indicators are calculated to accomplish the structural damage diagnosis. Finally, in this paper, the effect of the wavelet packet decomposition level and the structural damage feature vector on structural damage diagnosis are also disscussed, and the effect of structural damage diagnosis based on wavelet analysis is compared to that of wavelet packet analysis.The results show that the wavelet packet analysis method is more suitable than the wavelet analysis method for structural damage diagnosis. Damage diagnosis for structure can be made effectively by structural multi-scale damage analysis theory based on wavelet packet energy spectrum, and the sensitivity to structural damage is relatively high. Structural damage diagnosis would be accomplished accurately and efficiently with a rational choice of wavelet function, wavelet packet decomposition level and the structural damage feature vector.