Design-Testing And Modeling Of The Anti-leakage Magnetorheological Grease Damper

As we all know,China is one of the most earthquake-prone countries,and earthquakes in recent decades has caused immeasurable damage to our country.However,with the social and economic development,the buildings become higher and the span becomes wider,which results in greater seismic response.Therefore,in order to ensure that buildings do not collapse under the action of the earthquakes,higher requirements in seismic technology have been put forward.Magnetorheological(MR)damper,a member of magnetorheological vibration poof device,is an ideal and effective semis-active control device;with the advantages of large output,rapid response and adjustable,MR damper has been successfully applied in civil engineering.However,conventional MR damper still has disadvantages,easy settlement of magneto-rheological fluid,damper leakage,which restricting the application of MR damper.Because of the lack of MR damper,magneto-rheological grease can substitute for magneto-rheological fluid as energy dissipative material to reduce the settlement;the viscoelastic material is used creatively as a sealing device to solve the leakage problem of MR damper.Based on the idea,according to related standard,this paper presents the design principle of damper and determines the component size as well as internal magnetic circuit by finite element magnetic field analysis;finally the anti-leakage magnetorheological grease damper(MRGD)is made.Due to the sealing device of the anti-leakage MRGD composed of viscoelastic materials,the relatively soft viscoelastic materials will produce warp under the damper internal pressure.This paper analyses the influence of warp on anti-leakage MRGD and proposed magneto-rheological damping force coefficient to correct the damping force;combined with the damping force calculation of viscoelastic materials,the mechanical model of the anti-leakage MRGD is proposed.The sealing experiment of the anti-leakage MRGD is to text its sealing ability,which shows that the anti-leakage MRGD has good sealing performance.In the dynamic performance experiment,according to experimental results,the central part of the hysteresis curve is concave,which shows that the warp of the viscoelastic materials has a weakening effect on the damping force and proves that the theory of magneto-rheological damping force coefficient is correct in the establishment of the mechanical model of the anti-leakage MRGD.Compared with test results,the fitted mechanical model can preferably reflect the mechanical properties of the anti-leakage MRGD.Finally,because the warp of viscoelastic materials can reduce the damping force,the improved method,setting steel ring in viscoelastic materials,is proposed to control the deformation of the viscoelastic materials to obtain a large stroke on the anti-leakage MRGD.Based on finite element analysis,the simulation results show that the improved method is effective and when the anti-leakage MRGD can adapt to a larger stroke,the deformation of the viscoelastic material decreases.