Finite Element Model Updating Of Bridge Structure Based On Response Surface Technology

The finite element analysis has been widely used in bridge structure analysis,A precise finite element model plays an important role in the static and dynamic analysis of structures,damage identification and health monitoring.The initial finite element model,which is usually used for structural analysis,is built according to the design drawings.This inevitably assumes or simplifies the material properties and boundary conditions.There are some differences between the model and the actual structure,Therefore,it is necessary to modify the initial model by making full use of the measured static and dynamic load data to modify the structural parameters of the initial model,so that the modified model can better reflect the actual stress state of the structureAt present,the commonly used sensitivity based correction method has some disadvantages,such as the inaccurate screening parameters and the construction of the ill conditioned sensitivity matrix,which leads to slow convergence and even no convergence.Considering the advantages of the response surface method,this paper studies the application of the response surface method in the static and dynamic modification of the structural finite element model,This method not only has a small amount of calculation,but also has high correction efficiency,and the modified model can be used as the benchmark model for damage identification and health monitoring.Firstly,the theory of finite element model updating is introduced briefly,and the basic principle,basic process and key problems in the process of model correction are expounded.Then,the response surface method is introduced,and the basic principle of applying the response surface method to model correction is introduced.And the steps of the method are described.and the experimental design and optimization algorithm are introduced in detail.and the advantages and disadvantages of each experiment design and optimization algorithm are compared and analyzed in detail.Secondly,the application of the response surface method,combined with a single beam load test data,the static model of the single beam is modified.And the correction results confirmed the feasibility of the method.Finally,taking the Huang Gong bridge as the engineering background,with the measured structural frequency and deflection as the response value,the response surface method is used to analyze the static and dynamic characteristics of the bridge.Compared with the initial model,the calculated value is closer to the measured value,and the error of the frequency is reduced from about 10% to less than 1%.and the deflection error is reduced from 20% to less than 2%.Then,the modified model is verified by the measured data of other working conditions,and the error of the model is obviously reduced,which verifies the reliability of static and dynamic correction of the finite element model by using the response surface method.