Study On Cable Damage Identification Of Cable-Stayed Bridge Based On Statistical Analysis Under Moving Load

The research on bridge damage identification is a hot spot in the field of structural health detection,and the cable damage identification of cable-stayed bridge is the difficulty and focus in the field.Vibration response signals contain comprehensive structural information,which can accurately reflect the structural damage state.Therefore,damage identification using vibration corresponding signals is widely used in damage detection.In vibration signal detection,due to the large amount of test data and the interference of measurement noise,the recognition accuracy becomes worse.In order to reduce the influence of redundant information,this paper uses the statistical analysis method to process the vibration response data of stay cable,reduce the dimension and denoise,and constructs the calculation formula of damage index combined with the statistical moment of vibration response signal.Different working conditions are selected to determine the location of damaged cable.The specific work is as follows:(1)The principal component analysis is combined with the statistical moment of vibration response signal,and introduced into the cable damage location identification of cable-stayed bridge.This method first collects the vibration response signal of the cable structure when the moving load excites the bridge deck,then reduces the dimension of the vibration time-domain signal by using the principal component analysis method,constructs the calculation formula of the damage index combined with the statistical parameters of the reduced dimension vibration signal,and finally constructs the multi-order statistical moment fusion index through the D-S evidence theory,Based on this criterion,the cable damage of cable-stayed bridge is identified.In this paper,the vibration response of the proposed bridge is compared with that of the acceleration signal.The numerical simulation results show that the principal component analysis method has a good dimension reduction effect.On the premise that the vibration response signal data is huge and contains redundant information,the damage identification method can accurately identify the location of cables with different degrees of damage on the basis of effectively avoiding the influence of noise.(2)On the basis of principal component analysis,in order to better classify and reduce the dimension of nonlinear vibration response data,kernel principal component analysis is introduced into cable damage location identification of cable-stayed bridges.Firstly,the vibration response data is transformed into a high-dimensional space through nonlinear mapping,and then the dimension is reduced by principal component analysis in this high-dimensional space.The principal components of structural vibration response are extracted to achieve the purpose of signal noise reduction,and the statistical characteristics of vibration signals after dimensionality reduction are fused and calculated by D-S evidence theory to construct damage indicators.Through numerical simulation,the influence of load mass and load moving speed on damage identification is analyzed.It is found that too high load moving speed will have a great impact on the identification accuracy.By drawing the influence interference rate curve of load moving speed and moving load weight,the influence law of vehicle speed and vehicle weight on damage identification effect is explained.(3)In order to further improve the noise reduction effect and increase the sensitivity of damage identification,based on the damage identification research based on principal component extraction,the factor analysis method is introduced into the cable damage location identification of cable-stayed bridge.Firstly,the special factors of cable vibration response are extracted for signal noise reduction,and then the statistical characteristics of special factors are fused and calculated by D-S evidence theory to construct the damage index.Through numerical simulation,the effects of moving load mass and load moving speed on damage identification and the damage identification under multiple moving loads are analyzed.The analysis results show that this method can improve the detection efficiency and has better noise robustness.