Optimum Design For Multiple-Tuned-Mass-Damper Under Earthquake Excitation

Structural aseismic design is the main content of structural design in civil engineering, including the system of structural aseismic design, the method of structure aseismic calculation and the struture aseismic measures, in which the earthquake action is one of the major loads in structural design. It is one of effective ways of using vibration control technology to resist the earthquake action.The structure passive tuned control system is composed with main building and its substructure(a vibration control device called tuned mass dampers). The substructures have inherent mass stiffness and damping,so that we can tuned its natural frequency make which as close as possible to the natural frequency of the main mass or the excitation frequency .In such way,when the building is vibrating by seismically excitation, the main building's response will be effectively control.And the response will suffer a sharp deterioration by the tuned mass damper who can produce a inertial force which is opposite to the excitation's direction. A lot of tall buildings and towering structures with shearing model can be simplified as a multi-degree-of-freedoms(MDOF) system. MDOF vibration control technology has been substantially investigated to sustain the safety and serviceability of large civil engineering structures against strong winds or earthquakes. A number of newer tall buildings in the world are now equipped with various versions of such a system for vibration mitigation under vind and moderate earthquakes.Its analysis is very simple.when a tall building is equipped with a sigle TMD which only control a sigle model .Research in this aspect has been relatively complete , It was effective only when TMD's natural frequency was very close to the excitation frequency and it suffered a sharp deterioration in its performance if the excitation frequency deviated away from TMD's natural frequency. So many of researchers have study the performance of the MTMD in the excitation which have been placed into a tall building But these studies are based on just sigle model, there has been a resurgence of interest in their study of multi-models in recent years. In order to make the MTMD effective in control of high-rise buildings in seismic study,it is necessary to do the research in effectiveness of MTMD in linear multi-degree-of-freedoms structure's seismic response .Despite Jangid use Kanai-Tajimi seismic model and the mean square displacement of the minimum criteria for the preliminary study on the frequency of site soil excellence impact of MTMD effectiveness without the impact design MTMD on the optimal parameters (frequency interval (robust), the damping ratio and tuning frequency ratio) Therefore,it is necessary to do such reseach in these aspects systematically.It is one of effective ways of using vibration control technology to resist the earthquake action. The linear quadratic optimal control for algorithms of vibration structural control, is used to research optimal design for structural control system under earthquake actions in this paper .Assuming that the the number of control devices installed in asigned location, the parameter of control action was need to be optimized. There are 4 parts in this thesis as following:The first part is the analysis of the optimal system performance with the control of main mass response ratio and damper mass response ratio at first in this paper. The method of calculation of main mass response ratio and optimal system performance is analyzed, through examples demonstrate the multi-mass damping effects of passive tuning. We can obtain the comparation of the top of the displacement curves between under structural control system with 2 TMD and with no control device structure.Analysis results indicate that by the adoption of optimal control algorithm designing, the structure of the greatest displacement response has been effectively controlledThe second part is divided into optimal control system performance analysis. The method of calculation of optimal system performance index is analyzed at first in this paper.Optimal control system is evaluated by the function of optimal system performance index. When the performance index is the minimum value, the structural control is the optimal control.Then use the effective optimal control, design parameters of the TMD.Based on the weighted the Q matrix and R matrix repeatedly debugging, choose tthe best parameters by the optimal result.Finally be integrated the control system's optimization results.Part III is divided into structural vibration control system parameters optimized numerical simulation analysis.Firstly choose the simple three degrees of freedom model, the analysis in MATLAB of the two previous control system optimization methods and do numerical check. And then select the high-level framework of multi-span structure model,according to the control of the main structural dynamic response magnification factor and system performance indicators two methods platform, the system demonstrated the controller parameters , coupled multi-parameter optimization design by the assumption that the number and location of the controller.Part IV is divided into control system controller parameters on the use of ANSYS analysis of test results from the second optimization problem.By using the optimal design modules of ANSYS, the parameters of the passive controller design was discussed namely, its stiffness and damping parameters was optimized obtained viable secondary controller optimization methodIn the end, sum-up and prospect of the research in the task are stated.