Seismic Performance Of Base Isolation Structures With Turned Inerter-Based Dampers

Seismic isolation technology is a widely used seismic control method.By reducing the stiffness of the seismic isolation layer,the seismic response of the superstructure can be effectively reduced.In an ideal state,the superstructure behaves approximately as a rigid body during the earthquake.The displacement caused by the earthquake is mainly concentrated in the isolation layer,so the displacement of the isolation layer will be very large.In order to reduce the excessive displacement concentrated in the isolation layer,the mechanical properties and parameter optimization of two different forms of tuned inertial damper devices are studied in this paper.The main work of the thesis is as follows:(1)The mass amplification coefficient of the inerter are analyzed,two different forms of tuned inerter damper devices are taken as the research objects,and their mechanical models are respectively established.The equivalent elastic force and equivalent damping force provided by the tuned inerter dampers are analyzed,and the effectiveness of its vibration reduction through frequency analysis verified.(2)By improving the traditional genetic algorithm(GA),the global search capability of the GA is enhanced,the premature defects of the traditional GA are avoided,the convergence efficiency and calculation accuracy is improved.The effectiveness of the hybrid GA is verified by a 1-SDOF structure with an additional TMD device.(3)Based on a simplified model of a 2-SDOF seismic isolation structure,after attaching the tuned inerter damper device,the hybrid GA is used to search for the optimal parameters of the control device,and the effects of other parameters in the isolation system on the optimal parameters of the device are analyzed.At the same time,it is compared with the seismic response of an isolated structure without other control devices.(4)An eight-story frame isolation structure is taken as the research object,the stiffness of the isolation layer adopts a nonlinear constitutive.The seismic response of the seismic isolation structure is analyzed,and real seismic waves are used as excitation for verification.The influence of the yield stiffness ratio of seismic isolation supports on the optimal parameters and seismic response are compared,and the performance of the two tuned inerter damper devices in absorbing seismic input energy are compared.