Development Of Lead Extrusion Damper And Study On Structural Energy Dissipation

The technology of energy dissipation could be put in practice by designing some non-bearing elements of the structures as energy dissipating devices, or setting up dampers in the sensitive deformation positions of structures. Under strong wind or severe earthquake, the energy dissipating devices or dampers would enter the non-elastic state firstly, produce damping forces, dissipate large amount of energy, and reduce the dynamic response of the main structures. The successful implementation of the technology of energy dissipation depends on the excellent dampers and proper theory. In this paper the study results on energy dissipation in recent years are investigated and summarized, and the lead extrusion damper(LED) and the theory of energy dissipation are studied. The contents studied in this paper are as follows: The lead extrusion dampers are developed, and the composition of the LED is introduced. The analytical method and the finite element method are used to calculate the LED. The experiment system of LED is introduced, and the experiment scheme is designed. The experiment study is carried out detailed according to different combinations of vibration amplitudes and frequencies. Based on the data obtained in the experiment, the damping ratio and the stiffness of the LEDs are calculated corresponding to different frequencies and vibration amplitudes. The influence of the frequencies and vibration amplitudes on the parameters of the LED is studied, and the hysteretic behavior of the LED is analyzed. The results of the experiment study are compared with that of the theory analysis. The installation method of the lead extrusion damper in the structures is introduced, and the hysteretic model is presented when the LED and the brace are set up in series. The calculating formulae of this hysteretic model are analyzed. The equivalent damping ratio and stiffness coefficient of the LED device are studied, and the general equivalent formula of energy dissipation devices is established. In order to change the hysteretic model with break into continuous model, the method of Bouc-Wen is used. The result of calculating by equivalent model is compared with that by precise model. The construction characteristics of shear wall structures are introduced, and the mechanics performance and the seismic function of shear walls are analyzed. The vibration responses and the probable failure patterns of shear walls in severe earthquake are studied. The study results on seismic reduction of shear walls are investigated. The advantages and disadvantage of different methods of seismic reduction are analyzed. A new method of opening vertical slot and setting up dampers vertically is proposed. The computation theory of shear wall structures is introduced. The behavior of the shear wall structures with vertical installed dampers(VID) is analyzed. The calculation model of such structures is established and the computing method proposed. Meanwhile, the dynamic equations of structures with VIDs are deduced. The equations take into account the coupling action of the horizontal movement and the floor rotation. By discrete method, the relative energy equilibrium equation is established and each item in the equation is submitted, then the effect of energy dissipation of the structure with VIDs is evaluated. An example structure with VIDs is presented. The responses of the structure excited by ground motion are calculated. The responses of the lateral displacement, the floor rotation, the maximum lateral displacement, and the maximum rotational displacement are plotted or listed, and compared with the responses of the original structure. The VIDs could reduce the responses of the structure significantly. The input seismic energy and the damper-consumed energy are analyzed by the formulae proposed in the paper. The result shows that the dampers consume the earthquake energy mostly. The arrangement and the number of dampers in each floor would influence the vibration response largely. If the arrangement of dampers is rational, the better outcome of vibration reduction would be achieved, although the total number of dampers is less. Four performance indexes which depend on the maximum inter-floor displacement and the maximum floor acceleration are presented. The genetic algorithm is used to progress optimization computation, and the total number and the position of dampers are computed. The control effect of optimization is compared with that of non-optimization. Finally, the work in this paper is summarized and some conclusions about the study are drawn, besides, the future research problems are indicated.