Mechanical Performance Of MRD And Seismic Response Control For Suspension Arch Bridge By MRD

Magnetorheological damper(MRD)has the advantages of simple structure,large output,continuous adjustable damping force and good control effect.At present,the magnetorheological damper has been widely used in the research of structure shock absorption.The research on the damper is mainly focused on the structure,mechanical properties and mechanical model,and usually based on dynamic loading.But its mechanical properties under quasi-static loading are relatively rare;for multi-coil dampers,the relationship between the output of the damper and the number or the distribution of the coils is seldom studied.In this paper,the author load the four-magnetic-circuit shear-valve damper in different forms,its mechanical characteristics under different loading modes are obtained,and corresponding mechanical models are proposed.And by using the general finite element software ANSYS,a three-dimensional bar system model of a suspension arch bridge with magnetorheological dampers was established and the seismic response was studied.The specific research contents and results are as follows:(1)The author carried out quasi-static loading on the four-magnetic-circuit shear valve type magnetorheological damper;according to the test data,the damping forcedisplacement curve of the damper is drawn;and the author studied the damping force with displacement amplitude and the law of current change;the author also analyzes the reasons for the fluctuation of the damping force during the loading process;the author proposes the mechanical model of the damper under quasi-static loading and identifies the model parameters.(2)The four-magnetic-circuit shear-valve damper is loaded with low-cycle reciprocating load.Based on the experimental data,the damping force-displacement curve,damping force-velocity curve and energy dissipation curve of MRD are drawn,the law of damping force and energy dissipation performance changing with displacement amplitude,loading frequency and current is analyzed,and the applicability of Mi Model is identified(3)By changing the current status of the damper coil,the author obtains the experimental data of the damper when different coils are energized,and draws the damper force-displacement curve and the damper force-velocity curve,the relationship between the output of the damper and the electrification of different coils is analyzed(4)The spatial finite element model of suspender arch bridge with and without MRD is established,and its response time history under earthquake is analyzed to get its response under earthquake.The results show that the installation of MRD can effectively control the displacement response and acceleration response of suspender arch bridge under earthquake.The innovation of this paper is as follows:Based on the quasi-static test of MRD,a quasi-static mechanical model of the damper is proposed,which can accurately reflect the variation of the damping force with the current and displacement under the quasi-static force.Based on the finite element software ANSYS,a three-dimensional finite element model of suspender arch bridge with and without MRD is established,and its seismic performance is obtained The results show that the installation of MRD is beneficial to improve the seismic performance of the suspender arch bridge.