Damage Identification Of Steel Bridge Structures Based On Static And Dynamic Signals

Bridges are an important structural form in traffic engineering.As the years of service increase,the safety of bridge structures has received increasing attention from experts and scholars.The research on damage identification of bridge structures has become the focus of research in recent years.How to make the quantitative analysis of the damage location and damage degree of bridge structures fast and accurate land identification has become an urgent problem to be solved.Based on the above problems,this paper analyzes the damage of static and dynamic signals of steel bridge structures,including the following three aspects:(1)The integration law of the element in the stiffness matrix and the overall stiffness matrix is studied,as well as the correspondence between the element in the stiffness matrix and the overall stiffness matrix.Find the position of the element stiffness matrix in the overall stiffness matrix.In the overall structure coordinate system,a systematic association table is established according to the correlation between the number of cells and the number of nodes.It provides a simple method for the integration of the overall stiffness matrix of the combined structure and the positioning of the stiffness matrix of the component,while speeding up the efficiency of damage identification.(2)In the research of damage identification based on static signal in bridge structure,the stiffness sensitivity matrix is introduced for damage identification,and the relationship between deformation difference before and after damage of structural members is established.The least square method is used to solve the structural analysis model to obtain the damage factor of all structural members.The identification results under four different damage conditions are analyzed.At the same time,the static response test of the steel bridge model in the laboratory is an analyzed and compared,and the feasibility of the stiffness sensitivity matrix method is verified.(3)In the dynamic damage identification study,the flexibility matrix of the structure is calculated by using the first few modes which are easy to be measured in static or dynamic tests.The sensitivity matrix of the flexibility matrix and the eigenvalue are obtained by Taylor expansion while considering the eigenvalue of the structure.The damage analysis of bridge structure is carried out by using the combined sensitivity method of structure eigenvalue and flexibility sensitivity matrix,and the damage of different components in different degrees is simulated respectively.At the same time,the recognition under different measurement noise environment is considered,and the results are relatively good.Structural damage identification research is a complex work.Although the static signal identification method can be used for experimental analysis,it cannot get accurate results due to the measurement accuracy.There are some difficulties in practical operation.On the research of dynamic signals the damage identification using the frequency information of the structure can obtain better results,but the vibration mode parameters including more information of the structure are difficult to obtain in the actual measurement.The dynamic signal damage identification method adopted in this paper is also the finite element simulation based on the theory.It provides help for practical engineering application in the future.