Optimal Design Of Structural Vibration Control Using Tuned Liquid Dampers Based On H_∞ Theory

Earthquake is an extremely damaging natural disaster. The randomness and sudden of it have brought the research on vibration control a huge problem.Most of vibration control methods depend on the specific ground motion, and need to solve the equations of motion of the controlled structure system, which have complicated calculations. In fact, we often can not learn the exact model parameters of structure and the characteristics of unknown ground motion. To solve the problems above, passive control problem of building structures based on H∞control theory is discussed. View of that the tuned liquid damper have the advantage of economy, convenience, low maintenance costs, and good damping effect, in this thesis, the tuned liquid column damper (TLCD) is used for suppressing structural vibration.The main research contents include the following aspects:(1) A 3-story shear frame structure is selected as an example.The impact of weighted functions on parameters optimizition using the tuned liquid dampers and the change of frequency response curve is studied, in the same time, the effects on damping structural vibration and the time history of the structural response are analyzed when different weighted coefficients are adopted in objective functions.(2) An innovative optimal design method based on H∞norm is presented for the seismic response control of eccentric building structures using tuned liquid dampers. The H∞norm of the transfer function from the ground motion to the structural response is selected as the optimal objective. A numerical optional procedure is carried out by using Genetic Algorithms (GAs) in order to reach an optimal solution. The solving of equation of motion for the control system is unnecessary in the optimal design process and the obtained optimal parameters of dampers are not dependent on the ground motion records. A 12-story eccentric structure is selected as an example. The results showed that the tuned liquid dampers with optimal parameters acquired through the proposed method can effectively reduce the structural response in different site conditions.(3) A 5-story frame structure is analyzed as an example. The H∞robust control problem of uncertainty systems under the earthquake action is proposed. Respectively using H∞norm of transfer functions associated with the top floor displacement and acceleration as optimization objective, optimal design of TLCD system with parameters uncertainties is studied. A large number of numerical analysis results in frequency domain and time domain show that this optimization method considering parameters uncertainty can effectively suppress the peak displacement response and the maximum acceleration of structure, and is robust to the structural parameters perturbation.(4) In this thesis, the optimization method proposed has application in practical engineering project-Xing'hai Bay Financial Building in Dalian. Using ETABS to establish the finite element model of structure, modal analysis is carried out. In order to facilitate analysis, the finite element model is replaced by a simplified model. Numerical analysis shows that simplified method is reasonable. Respectively using the H∞norm of transfer functions associated with the top floor displacement and acceleration as optimization objective, parameters optimal design of TLCD system is studied. The optimization suggestion to meet the different project needs is given. Considering parameters uncertainties, optimal parameters of TLCD system are obtained by using Genetic Algorithms (GAs). Analysis in the frequency domain and time domain shows that the proposed algorithm is robust.