Research On Damage Diagnosis Of Truss Structure Based On Wavelet Packet Analysis

The rod system structure is a kind of structure widely used in the field of construction engineering.Once the structure is damaged in the use process,the service life of the structure will be affected at least,and the heavy loss will be caused.With the development of wavelet and wavelet packet analysis,it is more and more widely used in the field of damage diagnosis because of its sensitivity to singular signals.In this paper,based on previous studies,damage identification and location analysis of plane and space frame structures are carried out by means of finite element analysis and numerical simulation.The main contents of this paper are as follows:(1)The development process and research status of damage diagnosis were summarized,and the existing methods of damage identification were classified.Then the basic theory of wavelet analysis and wavelet packet decomposition is introduced.(2)Based on the planar single-layer model and multi-layer model,the first eight displacement modes of different damage degrees,different damage locations and different damage quantities were obtained by finite element analysis software,and the ability of wavelet analysis and wavelet packet decomposition for structural damage identification was discussed.The analysis results show that the direct wavelet analysis based on the displacement mode cannot identify the damage of the structure,and the curvature of the displacement mode needs to be analyzed by the wavelet to realize the damage localization.Through the wavelet packet decomposition of displacement mode and modal curvature signals,the structure damage can be identified and the damage location can be determined by using the high frequency signals after decomposition,which shows that the wavelet packet decomposition is superior to the wavelet analysis in damage identification.(3)By setting different damage conditions for spatial single-layer and multi-layer frame structures,wavelet packet was used to decompose the displacement modes,and then the decomposed high-frequency node signals were processed and reconstructed.The damage identification ability of the decomposed and reconstructed signals to spatial frame structures was discussed.The results show that the damage location of the structure can be determined according to the reconstructed signals.