Research On Finite Element Model Updating Of Bridge Structure Based On Improved Adaptive Genetic Algorithm And Response Surface Method

The finite element model of bridge structure has been widely used in engineering practice because it can accurately simulate the actual structure.However,there are some limitations in the finite element model itself,such as simplification of the actual situation and various assumptions,which lead to a certain deviation between the model calculation results and the measured values.Therefore,it is necessary to study the finite element model updating of bridge structure in order to obtain more accurate calculation model and results.At present,researchers have strong subjectivity in the parameter setting of the model,and the correction of all parameters seriously affects the correction efficiency.Therefore,this paper introduces the response surface method to improve the objectivity of the selection of correction parameters,uses the experimental design to complete the parameter analysis,and then completes the replacement of the finite element model through the explicit function,which overcomes the shortcomings of the finite element model that needs to be run repeatedly.In addition,the improved adaptive genetic algorithm is applied to the solution process of the response surface objective function,which can complete the correction of multiple parameters at the same time and improve the correction efficiency.The main contents of this paper are as follows :(1)In the process of using the improved adaptive genetic algorithm to solve the response surface objective function,the iterative mechanism of the basic genetic algorithm is analyzed and several improved forms are proposed.The improved adaptive genetic algorithm and several other genetic algorithms are used to solve the standard test function.By comparing the iterative efficiency and solution accuracy of several algorithms,it is found that the improved adaptive genetic algorithm has better solution performance.In addition,some key problems of response surface method are discussed,and a model updating method based on improved adaptive genetic algorithm and response surface method is proposed.(2)Taking a simply supported hollow slab as an example,the parameter significance analysis is carried out by combining the central composite experimental design and F test method,and the response surface objective function is constructed by using the field measured data,and the improved adaptive genetic algorithm is used to complete the solution,which verifies the efficiency of the improved adaptive genetic algorithm.The calculation error of the modified hollow slab model is significantly lower than that of the initial model,which proves the feasibility of the finite element model correction method based on the improved adaptive genetic algorithm and the response surface method.(3)Taking a river-crossing bridge LC in Sichuan Province as an engineering example,combined with the initial data and the measured data,the finite element model updating method based on improved adaptive genetic algorithm and response surface method is used to correct the material parameters of the cable,tower,steel beam,precast slab and side span beam,and the response surface model is used to fit.According to the static and dynamic characteristic information,the modified model is verified.The results show that the calculated value of the modified model is closer to the measured data,and the error between the two can be improved to a certain extent,which is more in line with the stress state of the actual structure.The correction method based on improved adaptive genetic algorithm and response surface method proposed in this paper effectively reduces the error between the finite element model and the actual structure,and can provide a more accurate finite element model for health monitoring and damage identification of bridge structures.