The Research On Reasonable Layout Of Viscous Dampers In Space Truss Structures

With the advancement of science and technology as well as the further study of theseismic method, energy dissipation technology is widely used in the seismic design ofstructures as a new and effective damping technology. The viscous damper is a commonlyused energy dissipation device; due to its simple structure, low cost and good dampingeffects, it is commonly used in the field of high-rise buildings, space structures, bridgesand other projects. At present, studies on the structure with viscous dampers have achievedsome results, but studies on the reasonable layout of viscous dampers are not enough.Especially for the large span space structure, due to its numerous members and complexdynamic response, it is always difficult to find out the reasonable layout of dampers. Howto simply and effectively find out the reasonable layout of viscous dampers to make themconsume energy and reduce vibration more effectively becomes a hot topic of the dampingresearch on space truss structures.In this paper, the structure, mechanical calculation model and damping principles ofviscous dampers were described firstly, and the seismic analysis methods of the viscouslydamped system were expressed. Aiming at the problem of arranging viscous dampersreasonably in space truss structures, a method for searching the sensitive areas of structuralvibration response, and then determining the reasonable layout of viscous dampers throughmodal combination was put forward. This method is based on the modal superpositionmethod, selecting the vibration modes with larger modal participation mass ratios in onedirection after the modal analysis on structures, multipling the vibration modes by theirrespective modal participation factors and adding the results of the multiplicationalgebraically, and then getting the diagram of the combination mode, the locations wheregraphical slope is bigger are the sensitive areas of structural vibration response in thedirection, namely the reasonable locations for setting viscous dampers. The sensitive areasof structural vibration response in other directions can be found out following the samesteps. Choosing a pyramid space grid as the research object，testing the effectiveness of thejudgment method for the reasonable layout of viscous dampers. The sensitive areas ofvibration response in the grid structure were obtained according to the implementation steps of the judgment method, setting viscous dampers there and making analysis for theseismic response of the grid structure by using the Fast Nonlinear Analysis (FNA) method,the results showed that better damping effects could be achieved when installing dampersin the sensitive areas of the structural vibration response. The model of a double-layercylindrical reticulated shell was established, to which modal analysis was made. Thesensitive areas of vibration response in the reticulated shell were found out through thejudgment method, and then the reasonable layout of viscous dampers was determined. Itturned out that the reasonable layout of viscous dampers determined by the judgmentmethod was the same with the previous research, indicating that this method is alsoapplicable in the double-layer cylindrical reticulated shell.The judgment method for the reasonable layout of viscous dampers proposed in thispaper is simple and effective; it can accurately determine the sensitive areas of structuralvibration response, offering a good reference to find out the reasonable layout of dampersquickly.