Research On WVD Damage Identification Method Based On Cable-stayed Bridge Model Test

Since the 18th century,with the need for transportation and the rise of major industries,bridges are developing rapidly.The rapid development of the bridge can be seen from the first 177 meters span of the rigid chain link bridge(Mann Channel Bridge)to the first major span of the George Washington Bridge in 1931,which exceeded 1000 meters.However,with the development of the bridge,the problems gradually appear.Under the long-term operation and various environmental influences,the bridge will suffer from different types of damage,or even may lead to the collapse of the bridge and casualties.Therefore,it is of great significance to establish a damage identification and assessment system based on bridges.In order to establish a health monitoring system,this paper has carried out the following work:1.Referring to the actual bridges and bridge models at home and abroad,the overall size and detail structure of the bridge model are investigated,a physical test model of cable-stayed bridge with replaceable components and high economy based on laboratory conditions is designed and built,and various sensors are installed on the model.2.Use ANSYS finite element software to build the finite element model of cable-stayed bridge.the element type of the bridge is selected according to different stress conditions and material characteristics,and the finite element model of the cable-stayed bridge is established.The data of cable force,displacement,strain and natural frequency are calculated and compared with the data collected by sensors in the test model.3.Research on damage methods.This paper introduces the application of Wigner-Ville(WVD)distribution cross term to damage identification,and designs MATLAB program with the help of MATLAB time-frequency analysis toolbox.According to the actual conditions such as sensor sensitivity,a simple beam model is established to control the damage and the WVD cross term identification method is applied to identify the damage of the test structure under moving load.Subsequently,extensive diagnosis of WVD damage identification under complex working conditions was carried out.4.Application of bridge model damage method.The above-mentioned finite element model and experimental model of cable-stayed bridge are designed for damage and WVD cross-term damage identification method is applied.Data are collected and analyzed by using damage identification method,sensitivity of processed signals to damage identification is explored,damage type,damage location and damage degree are judged,and regularity of data is found.