Sensitivity Analysis Of Damping Parameters Of Surrounding Support For The Evacuated Square Pyramid Grid

The damper's seismic principle is mainly through using viscous dampers to dissipate most of the energy in the input structure, so as to reduce the structure's vibration response, to ensure the structure's safety under earthquake. Current, seismic energy dissipation technology has become one main development direction for project of seismic research. In recent years, domestic and foreign scholars made a more systematic study on damping the structure, which has been applied to many high-rise structures, but made few study on applying vibration technology to space truss structure, which also lack systematic research. Using the middle-span evacuated square pyramid grid as subject, this thesis studies viscous damper's damping effect on such grid structure, summarizes factors and rules of the damping effect on such structures, and finally put forward a damping design plan for the middle-span evacuated grid structure. This illustrates the viscous damper's damping efficiency on such middle-span evacuated grid structure, and provides effective experience and data for the future in-depth damping theory and experiment study.Firstly, this paper introduces the relevance theory on the vibration control, retrospect the current research and application of viscous dampers, and clarify the background and content of this research. Structure of viscous dampers, factors affecting their performance and computational models are also introduced. After analyzing and comparing six commonly used damping analysis methods, fast nonlinear duration analysis method is identified as an appropriate method for this thesis. Then this thesis uses the finite element analysis software SAP2000 model to make the model established modal analysis, and gets cycle and mode of the network structure, and then enter the three-way seismic wave to the structure for the duration analysis, and grasp the dynamic characteristics, and then according to the existing dynamic characteristics, six different damper layout scheme are designed. Through contrasts of the different axial forces of control member bars and the different Z-displacements of control node in the controlled and uncontrolled states, a more reasonable program is selected, and indicates that a reasonable layout of damper on the grid structure can make a good damping effect. Under the situation of the certain damper layout, by changing the number of dampers, damping coefficient, damping index of the seismic waves of different frequencies and structural span, this thesis makes sensitivity analysis on evacuated grid structure for energy dissipation parameter. The analysis results indicate that although the damper has certain effect on the structure grid, the more is not the better. A reasonable amount for the damper, damping coefficient and damping index have obvious damping effect on evacuated grid structure. From the safety and reasonable respects, when the computation model is C₀=300⁵00kN·s/m,α=0.2⁰.4, the damping effect is better. When the network structure under certain aspect ratio conditions, the span of network structure's variation cannot change the damper's certain damping effect. For the middle-span evacuated grid structure used in this thesis, when the span is 30m 45m, the damper is the best.The results show that taking viscous dampers to do energy dissipation is still applicable for the medium span grid. The structure of medium span will get a better effect if choosing an appropriate damper layout, amount and damping parameters. The damping effect will be better if laying the damper along the short cross direction, in the middle of the bottom chord. It can be seen that viscous dampers is one kind of damping devices suitable for such medium-span truss structure.