Research On Structural Damage Identification Method Based On EMD And Wavelet Transform

During the period of service,the accumulation of damage may cause damage to the structure,which may cause huge economic losses and adverse social impacts.Therefore,if the structural damage can be identified and repaired in time,the accident rate will be greatly reduced.Based on the research of damage identification system,this paper proposes a damage identification method based on EMD and wavelet transform,and the correlation is verified by simply supported beam model.The results show that the method can effectively identify Structural damage location.The main work of this paper is as follows:(1)Based on the comprehensive analysis of damage identification research,this paper systematically studies the damage identification methods,focusing on the principle of damage identification based on wavelet transform and the principle of EMD decomposition.The results show that if the original signal with noise is analyzed directly,because the noise will cause abnormal points of the signal,it is easy to cause damage misjudgment.Therefore,if the effect of damage identification is improved,the original signal needs to be pre-denoised.(2)The effects of direct wavelet threshold denoising and EMD-wavelet threshold combined noise reduction are compared and analyzed.The results show that the noisy signal is decomposed by EMD to produce a series of simple and stable IMF,the wavelet threshold noise reduction of these IMF can select the appropriate threshold,decompose the number of layers and other parameters,so that the noise reduction effect is better than the direct wavelet threshold denoising effect.(3)The feasibility of the structural damage identification method based on EMD and wavelet transform is verified.Based on the simply supported beam model,the damage identification of noiseless data,noised data,wavelet threshold de-noising and combined EMD-wavelet threshold de-noising under different working conditions are carried out.It is shown that the structural damage identification method of EMD and wavelet transform has a better effect on single damage recognition.For multi-damageidentification,only the damage location with large damage degree can be identified.The method still needs to be improved.