Finite Element Model Updating Combining Dynamic And Static Response

Finite element method is widely used in bridge structure analysis due to its high precision and adaptability to various complex shapes.Practical finite element model of the bridge structure is based on the finite element theory,and is established based on the assumption of the abstract on the material properties and boundary conditions,so the analysis results is not rigorous.The actual application also verified the difference between the output response of the finite element model and the measured response of the structure.The finite element model can be modified by optimizing the model,so that the output response of the finite element model and the measured response of the structure are constantly approximated,the result is that the final finite element model can truly reflect the actual state of the bridge structure.The research of model updating method can make the initial analysis model more accurate,which can help to establish a more perfect bridge health monitoring system,and offers assistance for the damage identification and the repair and reinforcement of bridge structure.It can also provide designers with more economical design ideas,which has considerable engineering application value.The main work of this dissertation is as follows:(1)It generalized the course of study at home and abroad on the subject,and mainly introduced research significance and difficulties of this topic,the basic principle of model updating method,method of classification and their respective applicable scope,advantages and disadvantages and so on.(2)Two methods used in the finite element model updating-response surface method and substructure are briefly introduced in this dissertation,including its basic principles and concepts.The process of finite element model updating based on response surface method was introduced in detail.It included the classification and comparison of experimental design method,correct selection and significance analysis of design parameters,the selection of response surface model,the method of construction and precision inspection,the construction of objective function,and the choice of optimization algorithm of the response surface model.(3)The applicability of the finite element model updating based on response surface method is verified by examples.Based on a pedestrian bending bridge,a finite element analysis model was established to select the structural eigenvalues and significant parameters.The response surface model was constructed based on the response surface method and the initial finite element model was modified.Then the method was applied to the damage identification of the pedestrian bending bridge structure.The results showed that the response surface method performs well in the field of finite element model updating and structural damage identification,it has considerable practicality.(4)The method also works well for large and complex structures.With a extradosed cable-stayed bridge-WuHan sanguan Han river highway bridge as the background,according to the initial design parameters and substructure technique,the whole bridge is divided into several parts,and the initial finite element analysis model is established.The uniform design is used to arrange tests in order to get a number of sample data.The mathematical expressions of the response surface model were obtained and the precision test was carried out.Finally,the dynamic and static data collected by the bridge health monitoring system was used to optimize the objective function to obtain the revised value of the significant design parameters.The research results showed that when putting the revised value into the initial finite element model,the error between the output response of the finite element model with the measured response of the structure has a great improvement,which verified the feasibility to apply the finite element model updating method based on the response surface method and the substructure technique to practical engineering structure.