Research On Structural Damage Identification Method Based On CEEMD

In civil engineering,structural health monitoring system is a key part of all types of buildings in the safety operations.When various structures appear in civil engineering,various major accidents can often be triggered.In order to avoid such accidents,structural damage identification is particularly important.This paper reviews the research status of various types of structural damage identification methods,and briefly analyzes the advantages and disadvantages of structural damage identification methods which the current widely used,combined with Complementary Ensemble Empirical Mode Decomposition to identify structural damage,and the shearing structure model and a certain building structure in the measured earthquake are taken as examples to verify the method.The main work and conclusions are as follows:1)Since the general linear filter and the traditional band-pass filter have poor noise reduction effects on complex signals containing both white noise and intermittent noise,this paper applies the more popular morphological filters in recent years,using simulated signal for noise reduction test.The noise reduction effects of different filters composed of three structural elements are compared in the experiment.The results show that the generalized morphology filter can fully adaptively reduce noise for signals containing both white noise and intermittent noise,has a good noise reduction effect.2)The three methods among Empirical Mode Decomposition,Ensemble Empirical Mode Decomposition and Complementary Ensemble Empirical Mode Decomposition in signal decomposition are compared in detail.The reason of modal aliasing phenomenon is analyzed,taking the simulation signal and the measured response signal as examples,then compare the above three methods.The study found that the EMD method has obvious modal aliasing problem;Modal aliasing problem improved by adding noise assistance in Ensemble Empirical Mode Decomposition,but there are some shortcomings that the added noise is not completely eliminated;Complementary Ensemble Empirical Mode Decomposition can eliminate the influence of noise by adding paired positive and negative white noise on the basis of Ensemble Empirical Mode Decomposition,and greatly improve the modal mixing stacking phenomenon.3)The instantaneous frequency obtained by the Hilbert transform of the characteristic Intrinsic Mode Function component of the structural response can identify whether the structure is damaged and the time of damage,then establish a normalized Intrinsic Mode Function damage index of energy ratio to identify the location of damage.Three different damage conditions are set for the five-layer shear structure by numerical simulation.The damage identification is carried out by the above methods.The results show that the damage identification method is effective and feasible.4)The damage identification method based on the Complementary Ensemble Empirical Mode Decomposition is applied to the damage identification of the measured building structure after the earthquake.The recognition results prove that the method can better identify the damage of the building in the earthquake.It has certain feasibility and effectiveness.