The Seismic Response Analysis And Optimization Of Building Structure Installed Magenetorheological Fluid Damper

In recent years, the research on semi-active control has developed considerably owing to its attractive properties. The semi-active system combines the advantages of the active control system and passive control system. It has the same reliability as the passive control system, and the strong adaptability as the active control system. The device of semi-active system is simple and the energy needed is little in the system .All of those good characteristics makes semi-active system as the most promising method in the field of structure control recently. There are various types of devices used for semi-active control of structures. One of the best devices is the magenetorheological fluid (MRF) damper, which has received significant attention in recent years.In the thesis, the author makes a systematic study for the theory of semi-active control system based on magenetorheological fluid damper.Firstly, this paper takes a review of the development and the present situation in structure control research, and then makes a comprehensive evaluation about the prospect of the semi-active system.Secondly, this paper detailedly analyzes the state equation form of structural control in two different coordinate systems, then introduces the Linear Quadratic Regulator(LQR) optimal control algorithm. And the principle of semi-active control is presented.Thirdly, this paper proposes a modified clipped-optimal control strategy, basing on the comprehensive analysis to several idealized mechanical model for MRF damper. To verify the validity of the proposed strategy, the author compiled a relevant time-history program with Matlab language. Simulation analysis of a three-story structure is made, in which the MRF damper is taken as the passive control device and the semi-active control device respectively, and the research results are shown that semi-active control system is better than passive control system.Fourthly, the base-isolation system is studied, and the author finds that the validity of the base isolation system depends upon the dynamic characteristics of the earthquake ground motion, so a new system that can be effective for a wide range of ground excitation is necessary. Hybrid control strategies, consisting of the passive isolation system and MRF dampers, is proposed in this paper. The author complied a...