The Study On Vibration Control Of Mixed-layer Isolation System With TMD Under Earthquake

With the acceleration of urbanization and the increasing demand of human beings,the structural system is constantly changing and innovating,and sometimes there are some objective factors that limit the effect.Basic seismic isolation technology can no longer be applied to all buildings.A new type of layer spacing Seismic technology came into being.The seismic isolation layer is transferred from the foundation to the upper structure,the dynamic characteristics of the structure change,and the working mechanism also presents new characteristics.It is necessary to analyze its seismic performance.On the other hand,the raising of the seismic isolation layer causes an increase in the participation of non-seismic vibration modes,and the vibration control effect of the substructure is limited.Therefore,it is necessary to consider mixing other control devices to improve the performance of the system.The existence of the seismic isolation layer can absorb and dissipate part of the seismic energy and reduce the installation weight of the TMD mass block.At the same time,the existence of the TMD system can limit the deformation of the seismic isolation layer and extend the service life of the seismic isolation device.The working characteristics of the two complement each other.The implementation of a hybrid control system provides possibilities.This article mainly carried out the following work:(1)Based on the feasibility of the mixed use of TMD dampers and layer isolation technology,for different target control modes,two mixed-layer isolation systems with TMD on the top layer of the upper structure and the top layer of the lower structure are proposed,and the motion equations of the two are established.(2)Use ANSYS to build the third-stage 20-story Benchmark numerical model of the steel structure.From the mechanical properties of the seismic isolation support,the horizontal and vertical directions are simulated in the form of Combin40 and Combin14 combined units.The vibration control effect of the upper and lower structures of the seismic isolation layer is comprehensively considered.Establish five-layer isolation models of the first,third,fifth,seventh and ninth floors,and conduct modal analysis on them.(3)The Elcentro wave,Taft wave and artificial wave are selected as the input ground motion for time history analysis,and the structural response is used as the evaluation index to explore the influence of the change in the position of the seismic isolation layer on the horizontal seismic performance of the structure.(4)According to the results of modal analysis and time history analysis,two representative seismic isolation structures,one-story isolation and nine-story isolation,are selected,two hybrid isolation systems layout strategies are given,and a finite element model of the hybrid isolation structure is established.The author conducts dynamic time-history analysis and compares the vibration control effects with uncontrolled structures and only story-isolated structures.The research results show that the lower the isolation layer is set,the more obvious the period extension effect is.As the isolation layer shifts to the upper part of the structure,the non-isolation high-order mode participation coefficient increases.The seismic response of the floors near the seismic isolation layer has abrupt changes,and the upper structure has a significant response inhibition effect,but the acceleration of the lower structure is amplified.For the one-story seismic isolation structure,after attaching TMD to the top of the upper structure,the displacement of the seismic isolation layer is reduced,and the first-order mode response is further tuned.For the nine-story seismic isolation structure,after attaching TMD to the top of the lower structure,the lower structure The abrupt amplification condition of the slab can be alleviated,the second-order non-isolated vibration mode can be effectively controlled,and the hybrid control strategy has improved the overall working performance of the layer-isolated structure.