Mechanical Model Of Gyro-Mass Viscous Damping Devices Considering Negative Stiffness Effect: Analysis And Application

With the development of seismic technology of structures,active and passive vibration-reduced systems of structures have been widely used in vibration-reduction and seismic-resistance of building.Comparison with the previsous variable stiffness and variable damping control systems.The appearance of the gyro-mass viscous damper(GMD)becomes an optional type of damper.This paper focuses on the mechanical principles of GMD.The negative stiffness effect of GMD was discussed.And it was placed in single-degree-of-freedom(SDOF)systems,establishing three damper model.Frequency-domain and time-domain of three damper models were analyzed.Finally,the accuracy of equivalent linearization method(EQL)was verified to analyze the nonlinear systems.A preliminary study on the design method of the damper was carried out.The followings are the main research procedures and achievements,(1)Analyzing the operating mechanism of the GMD,obtaining parameterized mechanical model of the GMD,founding the axial dynamic equilibrium equation considering the friction force effect.Hysteresis loops of axial force,inertial force and displacement of the GMD were obtained.It is shown that GMD has negative stiffness effect.Then,the comparison between the model simulation results and the experimental results.The negative stiffness effect is discussed.(2)On the basis of the negative stiffness effect of the GMD.The effet of friction was ignored in this paper for simplicity.The GMD was placed in the SDOF structures,forming three damper models,which are damper model 1,damper model 2,damper model 3.Three models were compared with the conventional damper model.In damper model 1,the GMD makes the natural period of SDOF structure longer than the conventional SDOF structure.The results of damper model 2 show that the spring element is connected with GMD to decrease the influence of the GMD in high frequency region.Damper model 3 adds a damping unit,which is suitable for seismic structures under long-period ground motions.(3)The models of the time-domain analysis are the same as the frequency-domain analysis.Respectively,selecting the three different ground motions.The relative displacement response and acceleration response were taken as indexes,analyzing the sismic performance of the GMD.Damper model 1 significantly reduces the displacement response of the earthquake,comparing to conventional damper model.However,in soft soil areas,damper model 1 should be used with caution.In damper model 3,the spring/damping element in series with GMD can effectively reduce the relative displacement response and acceleration response of the structure.(4)A complex non-linear system is converted to a linear system by EQL.Under the action of the white noise and the filtered white noise,nonlinearity SDOF system was established on the basis of hysteretic restoring force model.Comparison of analysis results of EQL and nonlinearity system model.The feasibility of EQL to design and evaluate the dynamic response characteristics of hysteretic restoring force model systems was studied.