Dynamic Damage Identification And Analysis Method Of Simply Supported Beam Bridge Based On Moving Load

The difficulty of bridge structure damage identification is that response signal change is not obvious in the early damage case,which is hard to find a direct damage index to judge the damage location and degree,and many of the current damage identification methods can’t get away from the health structural response data,which limits the applicability of the methods.In order to solve the problem of the damage identification dependence on health structural response data and the situation difficultily to identify small damage,this paper proposes the dynamic damage identification and analysis method of simply supported beam bridge based on moving load,through the dynamic strain response in the damage state determines the damage position and attempts to quantify the damage degree,specific work is as follows:(1)A damage localization method of simply supported beam bridge is proposed based on strain variance under moving load,using the lifting wavelet transform and statistical theory,build up the strain variance local probability(SVLP3)damage index which is used to locate the damage.Taking simply supported beam bridge as the research object,the influence of various factors on damage identification is analyzed in numerical calculation.(2)Based on the pseudo-specific energy under moving load the damage localization method of simply supported beam bridge is proposed.Lifting wavelet transform is used to reconstruct the dynamic strain data of simply supported beam bridge,and the distribution curve of the average pseudo specific energy along the beam structure is obtained by calculating the pseudo specific energy response of each strain measuring point.The damage index of Smooth Ratio and Step Ratio(SRSR)is constructed by using smoothness analysis method for damage identification,which is applied to the numerical simulation and model experiment of a simply supported beam bridge.(3)The method for damage localization of simply supported beam bridge based on variation coefficient is proposed.By analyzing the relationship between strain statistical characteristics and damage,based on discrete wavelet transform and the finite difference method,construct the Double Curvature of Variation Coefficient of the strain response(DCVC)damage index.The proposed method is verified by finite element numerical simulation and model experiment of simply supported beam bridge.(4)This paper defines the identification method for simply supported beam bridge about strain modal parameter under moving load,Through the brinary discrete wavelet to separate the multi-order modal responses superimposed together by dynamic strain responses of simply supported bridge,and construct the First Strain Mode Curvature of strain response damage index ?C for damage localization,and use the method of inversion distance weighted average to inverse damage index before the damage,according to the model updating method to calculate the damage degree of simply supported beam bridge,and the numerical analysis and experiment of simply supported beam bridge proves the effectiveness of the proposed method.