Analysis Of Mechanism And Vibration Control Effect Of Cam-type Response Amplification Device With Friction Damper

The rigidity and bearing capacity of traditional seismic design structures have been enhanced to resist earthquakes.In this way,when the structures encounter medium and small earthquakes,the structural safety will be redundant,which may be insufficient under the action of strong earthquakes.With the promotion of energy dissipation technology,various types of dampers have been installed in the structures to consume the energy input during the earthquakes,and the dynamic responses of the structures will be significantly reduced.At present,dampers have been widely used in the field of engineering vibration control,but the structural responses are small under the action of small and medium earthquakes,and the energy dissipation effects of dampers cannot be fully exerted.Therefore,many response amplification devices have been proposed by scholars at home and abroad.The structural responses will be amplified by these devices and then input into the series-connected dampers,so that dampers can fully play a role in small and medium earthquakes.However,under the action of a large earthquake or a super-large earthquake,the huge responses of structures will be further amplified by these devices,causing the dampers to most likely exceed their ultimate bearing capacity.Through the above analysis,in order to solve the deficiencies of the dampers and the amplifying devices,our team has developed a cam-type response amplifying device(CRAD).The reciprocating motion of the cam mechanism has been fully utilized by CRAD,and the damper connected in series can achieve the response amplification effect,and effectively prevent the displacement of the damper from exceeding the limit.In this paper,a friction damper has been used in series with CRAD to form a cam-type response amplification device with friction damper(CRAD-FD).The mechanical performance of CRAD-FD has been deduced and verified by experiments,and its effect of vibration control in the building structures has been analyzed.The main research work is as follows:1.Deduction of restoring force model and pseudo-static test of the CRAD-FD.Firstly,the various components of CRAD-FD and their working mechanism have been introduced.Then the theoretical resilience and magnification formulations of CRAD-FD have been further deduced and improved.Furthermore,a pseudo-static test was performed on CRAD-FD,and the experimental results were compared with the above theoretical results,and the correctness of the theoretical formulations had been proved.Finally,the parameters analysis of CRAD-FD was carried out,and the optimization selection tables of parameters of CRAD have been given.2.Research on the control effect of the CRAD-FD under simple harmonic excitation.Firstly,the simple harmonic excitation control effect of CRAD-FD single degree of freedom(SDOF)system has been analyzed,and the simplified restoring force formulation of CRADFD has been given.Then the displacement analytical solution of SDOF system with CRAD-FD was derived by using the harmonic balance method.Finally,the energy analytical solution was derived by gradually integrating the dynamic equations of the SDOF system with CRAD-FD.3.Research on the control effect and reliability of the CRAD-FD.The MATLAB nonlinear seismic analysis program based on the smooth hysteresis BOUC-WEN structural restoring force model has been compiled.The control effect analysis and energy analysis of the uncontrolled SDOF system,the SDOF system with CRAD-FD and the SDOF system with traditional friction damper(FD)have been carried out respectively.The results show that:CRAD only needs to be connected in series with a small-tonnage friction damper,and the effect of vibration control of structures can be achieved or even better than that of directly installing a large-tonnage friction damper.At the same time,under the action of earthquakes at all levels,the friction damper connected in series with CRAD always reciprocates within the disc eccentricity,so its displacement will never exceed the limit.4.The secondary development of the CRAD-FD and the research on the energy seismic design method based on the behaviors.An energy design method based on the behaviors suitable for CRAD-FD energy dissipating structures has been proposed.In order to realize the applications of CRAD-FD in the solid model.The user-defined unit development function provided by ABAQUS has been used for the secondary development of CRAD-FD.Three natural ground motion records that meet the site conditions of the engineering calculation example had been selected,and the dynamic nonlinear finite element analysis of uncontrolled structures,structures with CRAD-FD installed and FD installed under rare and extremely rare earthquakes have been carried out respectively.The results show that the structures with CRAD-FD installed have better control effect than FD installed in story drift ratio,story drift and base shear force,and CRAD-FD has excellent energy consumption capacity.