Research On Vibration Reduction Mechanism And Optimal Design Of TMD Under Horizontal Structure

With the progress of society and economic development,the environmental vibration caused by urban traffic and modern industrial production has a negative impact on the structure itself,and the design of new buildings is also constantly moving towards beautiful and long-span development.Because of the relatively flexible stiffness,it is difficult to meet the specification requirements through its own structure.Therefore,the problem of floor vibration comfort has become a key issue,and also a problem that structural engineers often face in design.At present,there are two main methods to control the vibration response of the structure.The first one is to reduce the vibration of the structure,so as to improve the size and stiffness of the structure.The second is to install tuned mass damper and viscous damper on the structure.In order to solve the problem of vertical vibration control of long-span horizontal structure,TMD damping device is adopted in this paper,which has obvious control effect on the vibration of structure.At the same time,the occupied building area is small,convenient for installation,maintenance and replacement,economical and practical,and does not need external force.Because TMD device has many advantages,the following research and work are done on this basis:(1)This paper analyzes the single degree of freedom system,obtains the frequency domain solution through its motion equation,and analyzes the characteristics of the frequency-domain function,obtains the influence of each parameter on the TMD damping effect and the optimal parameter design method of the TMD system.(2)According to the characteristic analysis of multi degree of freedom system,the design method of MTMD damping system can be obtained by transforming the mode decoupling into a series of single degree of freedom system,and the layout principle should be installed in the place with large mode displacement.(3)The above methods are verified for practical engineering.Taking the steel box girder established by SAP2000 as an example,the vibration characteristics are studied.The effects of mass ratio,damping ratio,TMD frequency ratio and external excitation frequency on the vibration control effect of TMD are discussed.In view of the vibration comfort of a glass sightseeing trestle,MIDAS / Gen finite element model is establishedto study its vibration characteristics.The comfort of IABSE is analyzed by multi-point input and time history analysis,and the MTMD vibration reduction design and analysis are carried out according to the analysis results.The results show that the MTMD system designed by this method can effectively control the vertical vibration of the structure.The maximum vertical acceleration damping rate is 90%,and the average damping rate of each working condition is 80%.The research of this subject can not only provide reference for the study of TMD parameters,but also provide MTMD design ideas for solving the problem of building vibration comfort.