The Composite Inversion Of Wind Load And Structural Parameters Based On The Extended Kalman Filter

Damages may occur on a building structure due to the strong wind, earthquake or after a long-time service. Therefore, the composite inversion of structural parameters and external load becomes one of the important problems in structural health monitoring. Based on the summary about the study of composite inversion of structural parameters and external load at home and abroad, the main research of the thesis is the composite inversion of structural parameters and external load based on EKF. The main content of this paper is divided into the following parts:Firstly, a composite inversion of wind load and structural parameters is proposed based on EKF and the spatial correlation of wind load. The time history of wind load of high rise building is simulate d. Making use of spatial correlation of wind load of adjacent layers being closing to 1, the wind load of adjacent layers are taken as the same load to reduce the number of unknown loads and make the number of known responses be far greater than the number of unknown loads. Then, the structural parameters and wind load is inversed compositely based on EKF, taking the acceleration of each layer as the measurement. Moreover, the influence of spatial correlation of fluctuating wind and the initial values of the structural parameters are discussed.Secondly, a composite inversion of wind load and structural parameters is proposed based on EKF and the expansion of measuring degree of freedom. In the simplified model, the quality of columns will be concentrated to the particle different from the particle of floor, based on the finite element method, which makes the layer model of structures change into multi mass system model for realizing the extension of measuring number of degrees of freedom. At the basis of the extension of measuring degrees of freedom, the spatial correlation between adjacent layers is improved, the assumptions of taking the wind load of adjacent layers as the same load being more persuasive. Then the structural parameters and wind load is inversed compositely based on EKF, whose degree of freedom has been expanded. At the same time, the change of the accuracy inversion which is effected by different degrees of freedom is discussed.Finally, a composite inversion of wind load and structural para meters is proposed based on EKF and non-linear structure. The influence of main parameters in the Bouc-Wen model on the shape of hysteresis loop of the non-linear model is discussed based on Bouc-Wen model. What’s more, the parameters is selected according to the condition of the non-linear hysteretic loop. After introducing the normalized parameter to the structure whose bottom is Bouc-Wen model, the nonlinear model response is solved by Newmark-β. Then, the structural parameter of non-linear structure and wind load is inversed compositely based on EKF.The three part of the thesis is based on the composite inversion of wind load and structural parameters. The inversion based on EKF is proposed for linear and non-linear structure. The numerical example are presented to verify the feasibility of the algorithm and the results of chart analysis show high inversion precision.