Synchronized Identification Of Vessel-Bridge Collision Damage And Load Based On Sensitivity Analysis

Vessel-bridge collision accidents seriously threaten the safety of the bridge.The research on vessel-bridge collision mainly focuses on the prevention of vessel-bridge collision and the research on the anti-collision device of vessel-bridge collision.The research on the collision load and damage identification of bridge can determine the safety state of the structure in time after the collision and provide the basis for the rapid assessment of bridge after the disaster.Based on the National Natural Science Foundation of China's "Substructure-based Nonlinear Finite Element Model Revision and Damage Identification",this paper puts forward a method for identifying nonlinear structural parameters based on sensitivity analysis and take the Tanjiang Bridge of Shenzhen-Maoming Railway as the research object.The finite element model updating method under moving load is deduced,and the finite element model updating of Tanjiang Bridge on Shenzhen-Maoming Railway is carried out with monitoring data.Taking the modified finite element model of bridge as the object,the collision load and the damage of bridge body are identified simultaneously.In order to improve the computational efficiency,the synchronous identification method of vessel-bridge collision load and damage based on substructure is studied.This article mainly launches from the following four aspects:1.This thesis studies nonlinear structural parameter identification method based on sensitivity analysis.The motion equation of bilinear structure is deduced.The orthogonal coefficients of load are used to discretize the load,and the structural stiffness coefficients are used to discretize the structural stiffness.Then the sensitivity of the dynamic response of the structure to the orthogonal coefficients of load and the structural stiffness coefficients are calculated respectively.Finally,the optimal orthogonal coefficients of load and the structural stiffness coefficients are obtained by using the optimization iteration method based on sensitivity.2.This thesis studies the finite element model updating method under moving loads.The motion equation of bridge under moving train load is deduced,and the Chebyshev parametric expression of moving load and the parametric expression of structural stiffness are established.The sensitivity of dynamic response to theChebyshev polynomial coefficients and structural stiffness coefficients are solved by the identification method of non-linear structural parameters based on sensitivity analysis to optimize the search direction and complete the finite element model updating of bridge under moving load.3.This thesis studies synchronous identification method of vessel-bridge collision load and damage.The equation of motion is deduced,which is parameterized by load orthogonal term coefficients and structural stiffness coefficients.The sensitivity of structural dynamic response to collision load orthogonal term coefficients and structural stiffness coefficients are calculated by non-linear structural parameter identification method based on sensitivity analysis.Finally,collision load and bridge damage are identified synchronously.The ANSYS model is established to simulate the collision process of vessel-bridge,and the collision load and damage are obtained.The collision load and structural damage are identified by using the method of simultaneous identification of collision load and damage of vessel-bridge.The correctness of the method is verified by comparing the calculated results with that of ANSYS.4.This thesis studies synchronous identification method of vessel-bridge collision load and damage based on substructure.The energy index of vessel-bridge collision based on mean square root of acceleration is deduced to determine whether the vessel-bridge collision accident occurs and locate the collision position.The region near the collision position is divided into an independent substructure to be analyzed separately.The substructure motion equation expressed by load orthogonal term coefficients and structural stiffness coefficients are derived.The sensitivity matrix of substructure dynamic response to load orthogonal term coefficients and structural stiffness coefficients are derived to guide the change direction of the coefficients to be identified,and ultimately the collision load and sub-structure damage are identified simultaneously.By comparing the results of load and damage identification with those of ANSYS model,the correctness of the synchronous identification method of vessel-bridge collision load and damage based on substructure is verified.