Wavelet Analysis And Its Applied Research In The Complex For Structural Damage Detection

Wavelet analysis is a time-frequency analysis method which is a powerful tool to deal with non-stationary signals. Damage identification is an active research domain in current structure engineering and the kernel for structural health monitoring.In this thesis, damage location, damage extent and damage alarming are studied with wavelet analysis. The main subjects are summarized as follows:Common methods of damage identification and the application of wavelet transform are introduced .In the end, the develop trend in the domain of damage identification is expected.In this thesis, wavelet transform coefficient residual which is aimed at the characteristics of non-uniform stiffness of complex structure is presented in the thesis. Based on Runyang Bridge model, the obtained displacement mode is first imposed on wavelet transform. It is validated that damage location and damage extent are identified by defined wavelet transform coefficient residual before and after damage. Damage identification can be carried through accurately without displacement mode information of damage area, which is of great use for the optimal disposal of the sensors and decreasing the amount of sensors.Wavelet transform and multi-resolution analysis have remarkable effect in the online structural health monitoring. The sudden appearance of the damage will interfuse high-frequency components in the vibration response. The aim of damage alarming can be achieved by using wavelet transform to detect the high-frequency signal components. It is validated by wavelet of acceleration signal of a nine story shear building based on ambient excitation that the proposed damage detection method can detect the exact time when the damage occurs.