| Space grid structure has been widely used in many kinds of fields such as the public buildings and the industrial buildings for its novel structure, elegant architectural modeling and strong spanning capacity. Especially in recent years, with the development of some significant social economic activities, a number of high standard social public buildings have been finished, for example, sports venues,meeting exhibition halls,airport terminals, etc. Those buildings process practical functions,in the meanwhile,always be regarded as major projects of a city or a nation and become the landmark buildings. Therefore, it is particular essential to make sure their safety under the force of earthquake and typhoon. However, with the increase of these structures' span, height and more complicated structure form. According to the traditional design methods, engineering structure tend to produce larger dynamic response and cause destruction or collapse under the strong earthquakes or wind. In recent years, the rapid development of seismic control technology provides a new way to ensure the safety of this kind of structure.The paper focuses on the stress and deformation characteristics of space grid structure in earthquakes. Using the special physical and mechanical performance of Giant Magnetostrictive Material (GMM), the GMM active seismic control system, corresponding control theory and engineering application technology are developed. The main research contents include:(1) Based on the ample study of GMM deformation mechanism and its magnetic properties, two new actuators have been researched which treats GMM as core components and combines its with requirement of seismic response active control of space grid structure. Through magnetic field, magnetic circuit, preloading device, temperature control device all these aspects to analyses its operation principles and construction methods systematically, and put emphasis on the optimization and analysis of magnetic circuit, exploring the corresponding magnetic performance, establishing the actuator model of electromagnetic finite element analysis and design.(2) Adopting HT-2402 multi-function servo control test enginery, the magnetic-force coupling performance tests about GMM actuator are made in the paper. By analyzing the relationships between output performance and drive current under different preloading force, a optimal preloading to guarantee the output performance is fined. The laws between output force and output displacement is discussed, and according to the testing results, the current driving models of GMM actuator have been established which have good applicability.(3) The GMM magnetostrictive inverse effect mechanism is analyzed, and by discussing the since sensing properties of GMM actuator, the corresponding test research is made. The results summarizes the influence law of various parameters on the stress sensing properties and verify the application GMM actuator since sensing properties on space grid structure rods, and then, the basic principle and method of using it as since sensing actuators for structural seismic monitoring control is analyzed.(4) The composition and control theory of space grid structure active vibration control system is analyzed comprehensively. By introduce the modern control theory into it for establishing the structural state space equation. And then the paper do a further research about the finite element method of controlled structure active control, and the dynamic Finite element model of ordinary rods, GMM actuators, and GMM active rods in the space of grid structure have been deduced. Then the controlling position matrix establishing method of structure integrated GMM actuator have been deduced.(5) The paper also analyze GMM actuator's optimized allocation method in space grid structure and study the performance index of the layout merits of space grid structure active vibration control and then design a fitness function. Continually, an optimization strategy implementation is proposed based on Genetic Algorithm. Afterwards, the paper use MATLAB software compile the fitness function procedure and apply GADS toolbox to do the optimum computation. It can improve the optimization design of computational efficiency, meanwhile to ensure the realization of the integral structure optimization. Then by the MATLAB software, LQR control algorithm program is compiled so as to do the dynamic time-history calculation of space grid structure active control. By means of analyzing the dynamic time-history calculation in various working conditions, it can test and verify the effectiveness and feasibility of Genetic Algorithm to actuator's optimized allocation.(6) By analyzing the basic design theory of fuzzy control system and fuzzy controller, a double input and single output two dimensional fuzzy controller which makes full use of the fuzzy logic control toolbox of MATLAB software is designed. Based on the relationships between displacement and velocity, the paper seeks out the control strategy, and then gets the fuzzy control to suppress the structural reaction. Focusing on the fuzzy controller, the paper establishes a seismic response analysis system which used to simulate the seismic response of space grid structure under no control or fuzzy control by using SIMULINK in MATLAB software. A detailed introduction about the operation principles of the whole system and all these modules' functions are given. As a result, the on-line operation of space grid structure dynamic response fuzzy control simulation system will be realized.(7) Through reasonable design of active control strategy to simplify the controlling methods, the online real-time control have been achieved. The paper make an earthquake simulation vibration table test research to a Kiewit shell model structure in two different situations, which are setting GMM active rods and non-setting GMM active rods, and the test conditions have more than 10 kinds. Results show that, the active seismic control method and the corresponding active seismic control system could control model of seismic response of the structure. The control effect could reach more than 25% generally. The paper illustrates the correctness and effectiveness of GMM active control system and active control method. It also provides an theoretical and experimental basis for the application of active control technology in structural seismic response. |
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