Damage identification of structure and test study based on wavelet transform

Teeming with large-span and complex structure, it play a more and more important role in on-line monitor and diagnosis of structure health based on the advanced equipment and scientific methods. Not only the methods based on inherent frequency, or vibration mode changes, but also flexibility or stiffness changes measurement method, exist a common limitation which insufficient in the small and fatigue damage recognition because of theirs sensitivity. Wavelet transform integrate the advantage from time domain and frequency domain analysis, belong to time-frequency analysis method with multi-resolution, it has scalable, translation and zoom function and can be observe the signal use different yardsticks or resolution which achieve high resolution local orientation in time and frequency domain, it is very appropriate and necessary in non-stationary signal processing and meet the basic requirement for structural damage detection. In this paper, the delamination wavelet transform search method be derived to diagnosis the structure damage, then decompose the energy in the different band, through the energy changes to determine the extent of structural damage. The method is tested in a three-tier RC framework structure. The test results in good agreement with theoretical analysis, which proved that the method in this paper is feasibility and accuracy.