Experimental Study On Viscoelastic Damper Wall

Energy dissipation control are widely applied in civil engineering projectsand different types of dampers are developed for passive energy dissipationcontrol. The wall damper is one of newest devices with great prospect forapplication, which is easier to be fixed and flexible for layout. But less researchhas been done on this new form of the device and its design technology. And forviscoelastic dampers, more and more viscoelastic materials are developed tahtgreatly advances performance of viscoelastic dampers. Meanwhile, mechanicalproperties of viscoelastic dampers show some new characteristics. Therefore,practical mechanical models are needed for application and promotion ofviscoelastic damper.Focusing on the aforementioned issue, this paper presents an experimentalstudy on a new type viscoelastic damper, which is expected to have betterenergy dissipation capability. Tests on the dampers’ mechanical properties,including shear storage modulus, shear loss modulus, and loss factor, wereconducted using reduced scale specimens, and took strain amplitude, loadingfrequency and ambient temperature as test parameters. Aging tests, low cycleand high cycle fatigue tests were also conducted. Particularly, the low cyclefatigue behavior under a strain of300%and the basic mechanical behaviorunder strains of300%to420%were investigated. Test results suggest that thedependency of the mechanical properties on frequency and temperature aresmall, the energy dissipation capacity is stable for both large and smalldisplacement, and the damper reaches a strain of420%without failureBased on the test results, a new mechanical model of viscoelastic dampernamed “Bilinear-Kelvin” model, through that the dependency on displacementloading amplitude and velocity of damper performance can be considered, whichis meanful for the application of the viscoelastic damper on seismic projects.The model simulation results and test results show great accordance. Thennonlinear time history analysis is done to RC frame and RC frames added walldampers. Viscoelastic dampers and low yield steel dampers are added into theRCframe separately for comparision of seismic control effectiveness.Focusing on the wall form of the dampers, as added in the frame, thecharacteristic of the damper energy dissipation and the influence on the frame force analysis are studied theoretically. Simplified design method and someadvices are proposed to consider the amplification effect of damper deformationand influence on beam internal force in application.