Dynamic Response Analysis And Damage Identification Of Single-row Wharf Structure

As an important transportation infrastructure in China,the terminal's structural reliability is directly related to the safe operation of water transportation.However,due to the long-term service of many terminal structures,the damage has accumulated over time,which has affected the safe production and smooth operation of the port.Therefore,the damage identification of the terminal structure has become The current hotspots of the engineering community.In this paper,theoretical analysis,finite element numerical simulation,signal processing and other methods are used to deeply analyze and study the dynamic response,time-frequency energy spectrum and damage characteristics of pier single pile structure and single-row structure under non-damage state and damage state.An acceleration energy distribution analysis method for determining the existence of structural damage and a single-row structural damage identification method based on dynamic response are proposed.The main research contents and results are as follows:(1)According to the engineering characteristics of the single-row wharf structure,combined with the finite element theory and the constitutive model of the wharf structure,the finite element analysis model of the dynamic response of the single-pile structure and the single-row structure under the condition of no damage and damage is established.The excitation mode,the magnitude of the excitation force and the position of the characteristic response point of the dynamic response analysis of single pile structure and single row frame structure are drawn up.(2)Based on the dynamic response analysis model of single pile and single row frame under no damage and damage state,the modal analysis and transient dynamics analysis of single pile and single row frame structure under non-damage and damage state are respectively carried out.The natural frequency,periodic parameters and displacement,velocity and acceleration response curves of the structure under different working conditions are obtained.By comparing and analyzing the structural response characteristics under no damage and damage state,the acceleration response is proposed as the main basis for structural damage identification.(3)By comparing the characteristics of the acceleration response information received by different force positions and different response points of single-row structure under no damage and damage state,it is concluded that the single-row frame structure is subjected to transient load with amplitude of 2000 N.The response characteristics of the damage are more obvious within the range of 2m to 3.5m from the load point.By applying transient dynamic loads at different positions of the single-row structure,the analysis results show that the structural damage identification based on the acceleration response characteristics is better when the transient dynamic load is applied to the position of the upper surface of the pile and the intermediate surface of the beam.(4)Based on the wavelet energy spectrum theory and dynamic response analysis results,the acceleration energy spectrum changes of different structures are obtained by comparing the acceleration spectrum and time-frequency energy spectrum of single-pile and single-row structures.By analyzing the variation law of structural acceleration energy spectrum,the results show that the acceleration energy spectrum characteristics are closely related to the damage properties.On this basis,an analysis method of acceleration energy distribution for determining the existence of damage is proposed.(5)Based on the principle of Fourier transform,the characteristic parameters(A=a/mag2)of damage identification of single pile and single row frame structure are derived.By comparing and analyzing the damage identification characteristic parameter curve of damage-free and damage structure,the obtained The correlation between the dominant frequency variation and the energy distribution of the characteristic parameters.Based on this,a damage identification method based on dynamic response for single-row frame structure is proposed.(6)In order to verify the reliability of the damage identification method proposed in this paper,based on the actual engineering,the on-site acceleration measurement data was obtained,and the time-frequency energy spectrum characteristics and damage characteristic parameters of the test signal were analyzed.Based on the dynamic response,the single-row structure damage identification method is used to identify the damage of the engineering structure.The application results show that the single-row damage identification method proposed in this paper is feasible.