Study On Hybrid Simulation Of Friction Pendulum Isolated Structures Based On Online Model Updating

The hybrid simulation divides the whole structure into physical substructure and numerical substructure.The key parts with complex behavior are loaded on a large scale in the laboratory,and the rest are simulated by finite element software as numerical substructure.Therefore,it combines the advantages of physical test and numerical simulation,and can reflect the failure mechanism of the whole structure under earthquake loading.The accuracy of numerical substructure is one of the important factors that affect the reliability of hybrid simulation results.In order to improve the accuracy of the numerical substructure,the experimental data can be fully used to update the parts with similar boundary,material and behavior,so that the mechanical behavior of the numerical substructure and the experimental substructure are consistent.In this thesis,the hybrid simulation of friction pendulum isolated structure is carried out,the influence of online model updating technology on the hybrid simulation accuracy is studied,and the correctness and feasibility of online model updating method are verified.The main content of the thesis are as follows:1、The macroscopic mechanical model of friction pendulum bearing and the relationship between the coefficient of friction and sliding velocity,axial pressure,and temperature are summarized.Through the numerical simulation of friction pendulum isolated frame structures,the calculation results of different friction pendulum models were compared and analyzed.Considering the influence of surface pressure on the friction coefficient,the FPBearing PTV model developed by Kumar is selected for the online model updating hybrid simulation research;2、The FPBearing PTV element in Open Sees is redeveloped,and the reference coefficient of frictionμ_{re f} and axial pressure shape factor a_p are used as control parameters for online parameter identification and updating,so that they can be used as variables to predict and update according to the observed values of experimental data;3、An online model updating hybrid simulation platform is built by using the parameter identification algorithm of Unscented Kalman Filter.A program is written in Matlab to solve the equation of motion and identify the parameters.The communication interface between Matlab and Open Sees is established,and the hybrid simulation and friction pendulum parameter updating based on Matlab and Open Sees are realized.Numerical simulation results show that the accuracy of the hybrid simulation is improved by online model updating method.The error of numerical substructure is reduced effectively,and the effectiveness of the online model updating system is verified.4、An online model updating hybrid simulation of a four story friction pendulum isolated frame structures is carried out by using a six degree of freedom platform under horizontal unidirectional and bidirectional loading.The influence of experimental error on the identification algorithm of Unscented Kalman Filter is studied,and the reasonable parameter range is obtained.The results show that the Unscented Kalman Filter algorithm can identify the control parameters of the friction pendulum bearing element quickly and accurately under the two loading conditions.