Study On Damage Detection Of Beam Bridge Stucture Based On Wavelet Analysis

In this paper, the analysis mothod based on wavelet packet energy and the singularity detection theory are employed to analyze and identify the damage location and extent of the beam bridge structure. Which are summarized as follows:(1) The noise cancellation and the signal condensation are studied deeply in this paper, and some examples are showed.(2) The damage identification of several beam bridges is studied by emplying the method based on wavelet packet energy. And a series of bridges with different damage location and extent are sumulated mumerically. By using wavelet packet transform, the vibration signals are decomposed into component signals. Then, the damage location can be identified by the change of the wavelet packet component energy. Lastly, the identification results are gotten while the signals are interwaved by white noise.(3) The damage identification of beam bridges based on wavelet singularity detection theory is also researched. The vibration modes(or displacement) of a beam bridge under health or damage condition are analyzed with continuous wavelet transform by using of wavelet gaus2 and gaus1, and the Lipschitz exponent variation is researched with the change of damage extent, damage location, vibration modes,noise, load position , load magnitude, structure material and structure type.The wavelet theory is easy to understand in this paper, because it's continuity as the noise is considered, the application of wavelet is approached to the nature case; Especially, the method based on wavelet Gass1 is brought forward, which could be used for reference in this field. And because of the deep research of the Lip exponent, it will be understood more clearly how to indicate the damage extent.