Girder Bridge Vibration Response And Damage Identification Based On Vehicle-Bridge Interaction Vibration Analysis

Expressway girder bridges play a pivotal role in China’s transportation industry.However,due to the continuous development of China’s transportation industry,the number of vehicles is increasing,making the problems of usability and safety of highway bridges increasingly prominent.Therefore,how to ensure the normal use of the bridge and carry out accurate and timely maintenance work has become particularly important.However,at present,for ordinary highway continuous girder bridges,it is still a difficult task to not need to configure too many sensors and save test costs.The vibration response data collected by vehicles during the driving process of the bridge can be collated and analyzed,and the health status of the bridge structure can be evaluated to a certain extent.In this thesis,taking a medium-span continuous beam as an example,a vehicle-continuous beam coupling vibration model is established,and the damage of the continuous beam bridge is mainly studied by using vehicle excitation.The main research process of this thesis is as follows:(1)The coupling vibration analysis theory of axles is briefly described,and two methods to solve this problem are introduced.One of them is to establish a numerical model of vehicle load and bridge nonlinearity,and solve the dynamic balance equation;The other is to use finite element software modeling to solve the problem.In addition,this article describes two common ways to solve axle coupling problems:the display solution and the implicit solution.By analyzing the dynamic response of the vehicle and continuous beam at a specific position under the two methods,it is proved that the display analysis method performs better in solving the vibration response of the vehicle-continuous beam system in this thesis.(2)On the basis of actual engineering,the required simplified continuous beam model and vehicle model are established,and the simplified continuous beam model is compared in mode using the two simulation environments of Midas and LS-DYNA,and the effectiveness of the continuous beam model is verified.In addition,Hypermesh is also used to mesh the vehicle model,so as to establish a more refined vehicle model,so as to more realistically reflect the vibration response of the entire axle coupling system,and provide research conditions for the subsequent continuous beam without damage and damage.(3)The changes and correlations between vertical vibration displacement,vertical vibration velocity and vertical vibration acceleration under the action of coupling vibration of continuous girder bridge and vehicle in the injury-free state and damage state were studied.Based on the analysis results,the dynamic response of the continuous beam-vehicle coupling system of the bridge under different damage positions and damage degrees is analyzed in depth.Finally,considering that vehicle speed is an important environmental variable,the influence of different vehicle speed conditions on the damage recognition of continuous girder bridge is discussed in detail.(4)The application and development of machine learning and deep learning in bridge damage recognition are introduced,and a computational method based on convolutional neural network is proposed to solve the bridge damage recognition problem under axle coupling.According to the established neural network calculation model,the continuous beam damage condition set before is still taken,the vibration signal of the vehicle during driving is collected,and input into the neural network model for calculation and iterative analysis.