Study On The Mechanical Performance Of The Tuned Inertial Damper And Its Damping Performance To The Structure

The seismic performance of large-scale structures is the focus of research in the field of civil engineering.Especially,the vibration reduction system based on different types of dampers has always been one of the hotspots in the field of seismi c research.The traditional structure damping system only considers the influence of the single parameter change of damping coefficient,and with the development of the three-element vibration reduction system,the three-element vibration reduction technology which can consider the mass element,damping element and stiffness element at the same time has been developed rapidly.The eddy current damping element combines the inertial element with mass amplification effect to form a two--element vibration reduction system.On this basis,the three-element vibration reduction system formed by the coupled spring element has a tuning effect,which greatly improves the effect of structural vibration control.This paper will start with the research of axial eddy current damper with rotating inertia,and then focus on the vibration reduction effect of tuned viscous mass damper(TVMD)and tuned inertial mass damper(TID)on civil engineering structures.The main work completed is as follows:(1)The influence parameters and hysteretic performance of the axial eddy current inertial damper(ECVMD)is studied by electromagnetic finite element method and experimental test.The analysis shows that the eddy current damping force has significant velocity nonlinearity.The criti cal velocity in the velocity curve of the eddy current damping force is affected by the thickness and conductivity of the conductor barrel,while the initial damping coefficient and the maximum axial eddy current damping force are also affected by the size of the air gap and the number of permanent magnets.The hysteretic curve of the eddy current inertial damper measured by the test is full,which is consistent with the theoretical analysis results.(2)The displacement dynamic amplification factor of a single-degree-of-freedom structure under the control of multiple tuned frequency dampers(MTVMD,MTID)is deduced.Through numerical analysis,parameter optimization and seismic performance analysis of TVMD and TID with different structure damping ratio,mas s ratio and number of tuning frequencies were carried out.The results show that TVMD and TID have equivalent damping effects,which are better than VMD.The equivalent damping ratio of TVMD and TID nonlinear damping is deduced,and the influence of the velocity index on the optimal parameters of TVMD and TID is analyzed.The results show that the velocity index has a greater influence on the optimal damping coefficient,and the equivalent damping ratio of TVMD and TID is close to the optimal damping ratio of linear damping near the resonance frequency.(3)The robustness of MTMMD and MTID systems is analyzed when the main structural parameters change.The results show that the robustness of the system increases with the increase of the mass ratio and the nu mber of tuning frequencies,and the control effect is more sensitive to structural frequency changes.A calculation model with parameter deviations conforming to the normal distribution is proposed to consider the effect of the MTVMD and MTID parameter dev iations on the structural damping performance,and the damping performance of MT VMD and MTID is analyzed by the Monte Carlo test.The results show that the mass ratio and the number of sub dampers will affect the effectiveness and reliability of the system.(4)The multi-degree-of-freedom structure-MTVMD and MTID system equations of motion and their topological model equations of motion are established.Based on the complex modal analysis method and state space equations,the damper installation position,number and damping parameter model are used to analyze the dynamic characteristics As for the impact of shock absorption performance,the impact of damper support position changes on the shock absorption performance of the structure was compared and studied.(5)Based on a long-span self-anchored suspension bridge,the control effect of the tuned inertial damper on seismic response and vortex-induced resonance response is studied.The analysis shows that the TVMD and TID control systems can play a good control effect on longitudinal drift.When the mass ratio is 0.1,the damping efficiency of the two types of tuned inertia dampers on the peak displacement and root mean square of the beam end is about 45%;TMD,TVMD and double tuned inertial damper(RIDTMD)have good damping effects on vertical vortices resonance of bridges,and at the same mass ratio,RIDTMD has the best damping effect,followed by TVMD,both of which are better than the traditional TMD.