Damage Identification Of Bridge Structure Based On Wavelet Analysis

To solve the problem of bridge damage identification.In this paper,the wavelet transform is as a tool,use wavelet transform singularity theory and the wavelet packet energy method to study the damage structure.Then using the Lipschitz value and the wavelet packet energy change rate indicators to identify the damage location and damage degree of the structure,and achieved good results.And the experimental verification is carried out.Results show that,based on wavelet singularity analysis and wavelet packet energy change rate index can identify structural damage location and relative degree of damage.The specific contents are as follows:(1)A variety of damage structure identification methods are listed.And the theory of wavelet is introduced in detail;(2)Studied the damage identification of bridge structure based on the wavelet singularity theory.This paper simulated a simple supported beam by ANSYS software,and extracted the modal analysis' displacement.Then the signal is analyzed by wavelet transform,and the curve of the wavelet transform coefficient is obtained.The damage position and relative damage degree can be seen clearly from the curve,and the influence of different damage degree and location to the Lipschitz value is analyzed;(3)Studied the damage identification of bridge structure based on the wavelet packet energy method.Using ANSYS apply the same impact load to the simple supported beam with different damage degree,extract the nodes' acceleration signal.Using MATLAB to decompose the signal by wavelet packet,get the nodes' wavelet packet energies before and after the damage.By comparing the energy of the nodes before and after the damage,the damage position and the relative damage degree of the structure can be obtained by using statistical knowledge;(4)Carried out an experiment verify the wavelet packet method.The experiment was carried out with an organic glass simply supported beam,collected the acceleration signal of each node.Using wavelet packet energy rate index identify the structure's damage.Experiment shows that the wavelet packet energy method can be used to identify the damage location and damage degree of the structure.